//  Ramda v0.15.1
//  https://github.com/ramda/ramda
//  (c) 2013-2015 Scott Sauyet, Michael Hurley, and David Chambers
//  Ramda may be freely distributed under the MIT license.

;(function() {

  'use strict';

  /**
     * A special placeholder value used to specify "gaps" within curried functions,
     * allowing partial application of any combination of arguments,
     * regardless of their positions.
     *
     * If `g` is a curried ternary function and `_` is `R.__`, the following are equivalent:
     *
     *   - `g(1, 2, 3)`
     *   - `g(_, 2, 3)(1)`
     *   - `g(_, _, 3)(1)(2)`
     *   - `g(_, _, 3)(1, 2)`
     *   - `g(_, 2, _)(1, 3)`
     *   - `g(_, 2)(1)(3)`
     *   - `g(_, 2)(1, 3)`
     *   - `g(_, 2)(_, 3)(1)`
     *
     * @constant
     * @memberOf R
     * @category Function
     * @example
     *
     *      var greet = R.replace('{name}', R.__, 'Hello, {name}!');
     *      greet('Alice'); //=> 'Hello, Alice!'
     */
    var __ = { '@@functional/placeholder': true };

    var _add = function _add(a, b) {
        return a + b;
    };

    var _all = function _all(fn, list) {
        var idx = 0;
        while (idx < list.length) {
            if (!fn(list[idx])) {
                return false;
            }
            idx += 1;
        }
        return true;
    };

    var _any = function _any(fn, list) {
        var idx = 0;
        while (idx < list.length) {
            if (fn(list[idx])) {
                return true;
            }
            idx += 1;
        }
        return false;
    };

    var _assoc = function _assoc(prop, val, obj) {
        var result = {};
        for (var p in obj) {
            result[p] = obj[p];
        }
        result[prop] = val;
        return result;
    };

    var _cloneRegExp = function _cloneRegExp(pattern) {
        return new RegExp(pattern.source, (pattern.global ? 'g' : '') + (pattern.ignoreCase ? 'i' : '') + (pattern.multiline ? 'm' : '') + (pattern.sticky ? 'y' : '') + (pattern.unicode ? 'u' : ''));
    };

    var _complement = function _complement(f) {
        return function () {
            return !f.apply(this, arguments);
        };
    };

    /**
     * Basic, right-associative composition function. Accepts two functions and returns the
     * composite function; this composite function represents the operation `var h = f(g(x))`,
     * where `f` is the first argument, `g` is the second argument, and `x` is whatever
     * argument(s) are passed to `h`.
     *
     * This function's main use is to build the more general `compose` function, which accepts
     * any number of functions.
     *
     * @private
     * @category Function
     * @param {Function} f A function.
     * @param {Function} g A function.
     * @return {Function} A new function that is the equivalent of `f(g(x))`.
     * @example
     *
     *      var double = function(x) { return x * 2; };
     *      var square = function(x) { return x * x; };
     *      var squareThenDouble = _compose(double, square);
     *
     *      squareThenDouble(5); //≅ double(square(5)) => 50
     */
    var _compose = function _compose(f, g) {
        return function () {
            return f.call(this, g.apply(this, arguments));
        };
    };

    /**
     * Private `concat` function to merge two array-like objects.
     *
     * @private
     * @param {Array|Arguments} [set1=[]] An array-like object.
     * @param {Array|Arguments} [set2=[]] An array-like object.
     * @return {Array} A new, merged array.
     * @example
     *
     *      _concat([4, 5, 6], [1, 2, 3]); //=> [4, 5, 6, 1, 2, 3]
     */
    var _concat = function _concat(set1, set2) {
        set1 = set1 || [];
        set2 = set2 || [];
        var idx;
        var len1 = set1.length;
        var len2 = set2.length;
        var result = [];
        idx = 0;
        while (idx < len1) {
            result[result.length] = set1[idx];
            idx += 1;
        }
        idx = 0;
        while (idx < len2) {
            result[result.length] = set2[idx];
            idx += 1;
        }
        return result;
    };

    var _containsWith = function _containsWith(pred, x, list) {
        var idx = 0, len = list.length;
        while (idx < len) {
            if (pred(x, list[idx])) {
                return true;
            }
            idx += 1;
        }
        return false;
    };

    var _createMapEntry = function _createMapEntry(key, val) {
        var obj = {};
        obj[key] = val;
        return obj;
    };

    /**
     * Create a function which takes a comparator function and a list
     * and determines the winning value by a compatator. Used internally
     * by `R.maxBy` and `R.minBy`
     *
     * @private
     * @param {Function} compatator a function to compare two items
     * @category Math
     * @return {Function}
     */
    var _createMaxMinBy = function _createMaxMinBy(comparator) {
        return function (valueComputer, list) {
            if (!(list && list.length > 0)) {
                return;
            }
            var idx = 1;
            var winner = list[idx];
            var computedWinner = valueComputer(winner);
            var computedCurrent;
            while (idx < list.length) {
                computedCurrent = valueComputer(list[idx]);
                if (comparator(computedCurrent, computedWinner)) {
                    computedWinner = computedCurrent;
                    winner = list[idx];
                }
                idx += 1;
            }
            return winner;
        };
    };

    /**
     * Optimized internal two-arity curry function.
     *
     * @private
     * @category Function
     * @param {Function} fn The function to curry.
     * @return {Function} The curried function.
     */
    var _curry1 = function _curry1(fn) {
        return function f1(a) {
            if (arguments.length === 0) {
                return f1;
            } else if (a != null && a['@@functional/placeholder'] === true) {
                return f1;
            } else {
                return fn(a);
            }
        };
    };

    /**
     * Optimized internal two-arity curry function.
     *
     * @private
     * @category Function
     * @param {Function} fn The function to curry.
     * @return {Function} The curried function.
     */
    var _curry2 = function _curry2(fn) {
        return function f2(a, b) {
            var n = arguments.length;
            if (n === 0) {
                return f2;
            } else if (n === 1 && a != null && a['@@functional/placeholder'] === true) {
                return f2;
            } else if (n === 1) {
                return _curry1(function (b) {
                    return fn(a, b);
                });
            } else if (n === 2 && a != null && a['@@functional/placeholder'] === true && b != null && b['@@functional/placeholder'] === true) {
                return f2;
            } else if (n === 2 && a != null && a['@@functional/placeholder'] === true) {
                return _curry1(function (a) {
                    return fn(a, b);
                });
            } else if (n === 2 && b != null && b['@@functional/placeholder'] === true) {
                return _curry1(function (b) {
                    return fn(a, b);
                });
            } else {
                return fn(a, b);
            }
        };
    };

    /**
     * Optimized internal three-arity curry function.
     *
     * @private
     * @category Function
     * @param {Function} fn The function to curry.
     * @return {Function} The curried function.
     */
    var _curry3 = function _curry3(fn) {
        return function f3(a, b, c) {
            var n = arguments.length;
            if (n === 0) {
                return f3;
            } else if (n === 1 && a != null && a['@@functional/placeholder'] === true) {
                return f3;
            } else if (n === 1) {
                return _curry2(function (b, c) {
                    return fn(a, b, c);
                });
            } else if (n === 2 && a != null && a['@@functional/placeholder'] === true && b != null && b['@@functional/placeholder'] === true) {
                return f3;
            } else if (n === 2 && a != null && a['@@functional/placeholder'] === true) {
                return _curry2(function (a, c) {
                    return fn(a, b, c);
                });
            } else if (n === 2 && b != null && b['@@functional/placeholder'] === true) {
                return _curry2(function (b, c) {
                    return fn(a, b, c);
                });
            } else if (n === 2) {
                return _curry1(function (c) {
                    return fn(a, b, c);
                });
            } else if (n === 3 && a != null && a['@@functional/placeholder'] === true && b != null && b['@@functional/placeholder'] === true && c != null && c['@@functional/placeholder'] === true) {
                return f3;
            } else if (n === 3 && a != null && a['@@functional/placeholder'] === true && b != null && b['@@functional/placeholder'] === true) {
                return _curry2(function (a, b) {
                    return fn(a, b, c);
                });
            } else if (n === 3 && a != null && a['@@functional/placeholder'] === true && c != null && c['@@functional/placeholder'] === true) {
                return _curry2(function (a, c) {
                    return fn(a, b, c);
                });
            } else if (n === 3 && b != null && b['@@functional/placeholder'] === true && c != null && c['@@functional/placeholder'] === true) {
                return _curry2(function (b, c) {
                    return fn(a, b, c);
                });
            } else if (n === 3 && a != null && a['@@functional/placeholder'] === true) {
                return _curry1(function (a) {
                    return fn(a, b, c);
                });
            } else if (n === 3 && b != null && b['@@functional/placeholder'] === true) {
                return _curry1(function (b) {
                    return fn(a, b, c);
                });
            } else if (n === 3 && c != null && c['@@functional/placeholder'] === true) {
                return _curry1(function (c) {
                    return fn(a, b, c);
                });
            } else {
                return fn(a, b, c);
            }
        };
    };

    var _dissoc = function _dissoc(prop, obj) {
        var result = {};
        for (var p in obj) {
            if (p !== prop) {
                result[p] = obj[p];
            }
        }
        return result;
    };

    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is#Polyfill
    // SameValue algorithm
    // Steps 1-5, 7-10
    // Steps 6.b-6.e: +0 != -0
    // Step 6.a: NaN == NaN
    var _eq = function _eq(x, y) {
        // SameValue algorithm
        if (x === y) {
            // Steps 1-5, 7-10
            // Steps 6.b-6.e: +0 != -0
            return x !== 0 || 1 / x === 1 / y;
        } else {
            // Step 6.a: NaN == NaN
            return x !== x && y !== y;
        }
    };

    var _filter = function _filter(fn, list) {
        var idx = 0, len = list.length, result = [];
        while (idx < len) {
            if (fn(list[idx])) {
                result[result.length] = list[idx];
            }
            idx += 1;
        }
        return result;
    };

    var _filterIndexed = function _filterIndexed(fn, list) {
        var idx = 0, len = list.length, result = [];
        while (idx < len) {
            if (fn(list[idx], idx, list)) {
                result[result.length] = list[idx];
            }
            idx += 1;
        }
        return result;
    };

    // i can't bear not to return *something*
    var _forEach = function _forEach(fn, list) {
        var idx = 0, len = list.length;
        while (idx < len) {
            fn(list[idx]);
            idx += 1;
        }
        // i can't bear not to return *something*
        return list;
    };

    var _forceReduced = function _forceReduced(x) {
        return {
            '@@transducer/value': x,
            '@@transducer/reduced': true
        };
    };

    /**
     * @private
     * @param {Function} fn The strategy for extracting function names from an object
     * @return {Function} A function that takes an object and returns an array of function names.
     */
    var _functionsWith = function _functionsWith(fn) {
        return function (obj) {
            return _filter(function (key) {
                return typeof obj[key] === 'function';
            }, fn(obj));
        };
    };

    var _gt = function _gt(a, b) {
        return a > b;
    };

    var _has = function _has(prop, obj) {
        return Object.prototype.hasOwnProperty.call(obj, prop);
    };

    var _identity = function _identity(x) {
        return x;
    };

    /**
     * Tests whether or not an object is an array.
     *
     * @private
     * @param {*} val The object to test.
     * @return {Boolean} `true` if `val` is an array, `false` otherwise.
     * @example
     *
     *      _isArray([]); //=> true
     *      _isArray(null); //=> false
     *      _isArray({}); //=> false
     */
    var _isArray = Array.isArray || function _isArray(val) {
        return val != null && val.length >= 0 && Object.prototype.toString.call(val) === '[object Array]';
    };

    /**
     * Determine if the passed argument is an integer.
     *
     * @private
     * @param {*} n
     * @category Type
     * @return {Boolean}
     */
    var _isInteger = Number.isInteger || function _isInteger(n) {
        return n << 0 === n;
    };

    /**
     * Tests if a value is a thenable (promise).
     */
    var _isThenable = function _isThenable(value) {
        return value != null && value === Object(value) && typeof value.then === 'function';
    };

    var _isTransformer = function _isTransformer(obj) {
        return typeof obj['@@transducer/step'] === 'function';
    };

    var _lt = function _lt(a, b) {
        return a < b;
    };

    var _map = function _map(fn, list) {
        var idx = 0, len = list.length, result = [];
        while (idx < len) {
            result[idx] = fn(list[idx]);
            idx += 1;
        }
        return result;
    };

    var _multiply = function _multiply(a, b) {
        return a * b;
    };

    var _nth = function _nth(n, list) {
        return n < 0 ? list[list.length + n] : list[n];
    };

    /**
     * internal path function
     * Takes an array, paths, indicating the deep set of keys
     * to find.
     *
     * @private
     * @memberOf R
     * @category Object
     * @param {Array} paths An array of strings to map to object properties
     * @param {Object} obj The object to find the path in
     * @return {Array} The value at the end of the path or `undefined`.
     * @example
     *
     *      _path(['a', 'b'], {a: {b: 2}}); //=> 2
     */
    var _path = function _path(paths, obj) {
        if (obj == null) {
            return;
        } else {
            var val = obj;
            for (var idx = 0, len = paths.length; idx < len && val != null; idx += 1) {
                val = val[paths[idx]];
            }
            return val;
        }
    };

    var _prepend = function _prepend(el, list) {
        return _concat([el], list);
    };

    var _quote = function _quote(s) {
        return '"' + s.replace(/"/g, '\\"') + '"';
    };

    var _reduced = function _reduced(x) {
        return x && x['@@transducer/reduced'] ? x : {
            '@@transducer/value': x,
            '@@transducer/reduced': true
        };
    };

    /**
     * An optimized, private array `slice` implementation.
     *
     * @private
     * @param {Arguments|Array} args The array or arguments object to consider.
     * @param {Number} [from=0] The array index to slice from, inclusive.
     * @param {Number} [to=args.length] The array index to slice to, exclusive.
     * @return {Array} A new, sliced array.
     * @example
     *
     *      _slice([1, 2, 3, 4, 5], 1, 3); //=> [2, 3]
     *
     *      var firstThreeArgs = function(a, b, c, d) {
     *        return _slice(arguments, 0, 3);
     *      };
     *      firstThreeArgs(1, 2, 3, 4); //=> [1, 2, 3]
     */
    var _slice = function _slice(args, from, to) {
        switch (arguments.length) {
        case 1:
            return _slice(args, 0, args.length);
        case 2:
            return _slice(args, from, args.length);
        default:
            var list = [];
            var idx = 0;
            var len = Math.max(0, Math.min(args.length, to) - from);
            while (idx < len) {
                list[idx] = args[from + idx];
                idx += 1;
            }
            return list;
        }
    };

    /**
     * Polyfill from <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString>.
     */
    var _toISOString = function () {
        var pad = function pad(n) {
            return (n < 10 ? '0' : '') + n;
        };
        return typeof Date.prototype.toISOString === 'function' ? function _toISOString(d) {
            return d.toISOString();
        } : function _toISOString(d) {
            return d.getUTCFullYear() + '-' + pad(d.getUTCMonth() + 1) + '-' + pad(d.getUTCDate()) + 'T' + pad(d.getUTCHours()) + ':' + pad(d.getUTCMinutes()) + ':' + pad(d.getUTCSeconds()) + '.' + (d.getUTCMilliseconds() / 1000).toFixed(3).slice(2, 5) + 'Z';
        };
    }();

    var _xdropRepeatsWith = function () {
        function XDropRepeatsWith(pred, xf) {
            this.xf = xf;
            this.pred = pred;
            this.lastValue = undefined;
            this.seenFirstValue = false;
        }
        XDropRepeatsWith.prototype['@@transducer/init'] = function () {
            return this.xf['@@transducer/init']();
        };
        XDropRepeatsWith.prototype['@@transducer/result'] = function (result) {
            return this.xf['@@transducer/result'](result);
        };
        XDropRepeatsWith.prototype['@@transducer/step'] = function (result, input) {
            var sameAsLast = false;
            if (!this.seenFirstValue) {
                this.seenFirstValue = true;
            } else if (this.pred(this.lastValue, input)) {
                sameAsLast = true;
            }
            this.lastValue = input;
            return sameAsLast ? result : this.xf['@@transducer/step'](result, input);
        };
        return _curry2(function _xdropRepeatsWith(pred, xf) {
            return new XDropRepeatsWith(pred, xf);
        });
    }();

    var _xfBase = {
        init: function () {
            return this.xf['@@transducer/init']();
        },
        result: function (result) {
            return this.xf['@@transducer/result'](result);
        }
    };

    var _xfilter = function () {
        function XFilter(f, xf) {
            this.xf = xf;
            this.f = f;
        }
        XFilter.prototype['@@transducer/init'] = _xfBase.init;
        XFilter.prototype['@@transducer/result'] = _xfBase.result;
        XFilter.prototype['@@transducer/step'] = function (result, input) {
            return this.f(input) ? this.xf['@@transducer/step'](result, input) : result;
        };
        return _curry2(function _xfilter(f, xf) {
            return new XFilter(f, xf);
        });
    }();

    var _xfind = function () {
        function XFind(f, xf) {
            this.xf = xf;
            this.f = f;
            this.found = false;
        }
        XFind.prototype['@@transducer/init'] = _xfBase.init;
        XFind.prototype['@@transducer/result'] = function (result) {
            if (!this.found) {
                result = this.xf['@@transducer/step'](result, void 0);
            }
            return this.xf['@@transducer/result'](result);
        };
        XFind.prototype['@@transducer/step'] = function (result, input) {
            if (this.f(input)) {
                this.found = true;
                result = _reduced(this.xf['@@transducer/step'](result, input));
            }
            return result;
        };
        return _curry2(function _xfind(f, xf) {
            return new XFind(f, xf);
        });
    }();

    var _xfindIndex = function () {
        function XFindIndex(f, xf) {
            this.xf = xf;
            this.f = f;
            this.idx = -1;
            this.found = false;
        }
        XFindIndex.prototype['@@transducer/init'] = _xfBase.init;
        XFindIndex.prototype['@@transducer/result'] = function (result) {
            if (!this.found) {
                result = this.xf['@@transducer/step'](result, -1);
            }
            return this.xf['@@transducer/result'](result);
        };
        XFindIndex.prototype['@@transducer/step'] = function (result, input) {
            this.idx += 1;
            if (this.f(input)) {
                this.found = true;
                result = _reduced(this.xf['@@transducer/step'](result, this.idx));
            }
            return result;
        };
        return _curry2(function _xfindIndex(f, xf) {
            return new XFindIndex(f, xf);
        });
    }();

    var _xfindLast = function () {
        function XFindLast(f, xf) {
            this.xf = xf;
            this.f = f;
        }
        XFindLast.prototype['@@transducer/init'] = _xfBase.init;
        XFindLast.prototype['@@transducer/result'] = function (result) {
            return this.xf['@@transducer/result'](this.xf['@@transducer/step'](result, this.last));
        };
        XFindLast.prototype['@@transducer/step'] = function (result, input) {
            if (this.f(input)) {
                this.last = input;
            }
            return result;
        };
        return _curry2(function _xfindLast(f, xf) {
            return new XFindLast(f, xf);
        });
    }();

    var _xfindLastIndex = function () {
        function XFindLastIndex(f, xf) {
            this.xf = xf;
            this.f = f;
            this.idx = -1;
            this.lastIdx = -1;
        }
        XFindLastIndex.prototype['@@transducer/init'] = _xfBase.init;
        XFindLastIndex.prototype['@@transducer/result'] = function (result) {
            return this.xf['@@transducer/result'](this.xf['@@transducer/step'](result, this.lastIdx));
        };
        XFindLastIndex.prototype['@@transducer/step'] = function (result, input) {
            this.idx += 1;
            if (this.f(input)) {
                this.lastIdx = this.idx;
            }
            return result;
        };
        return _curry2(function _xfindLastIndex(f, xf) {
            return new XFindLastIndex(f, xf);
        });
    }();

    var _xmap = function () {
        function XMap(f, xf) {
            this.xf = xf;
            this.f = f;
        }
        XMap.prototype['@@transducer/init'] = _xfBase.init;
        XMap.prototype['@@transducer/result'] = _xfBase.result;
        XMap.prototype['@@transducer/step'] = function (result, input) {
            return this.xf['@@transducer/step'](result, this.f(input));
        };
        return _curry2(function _xmap(f, xf) {
            return new XMap(f, xf);
        });
    }();

    var _xtake = function () {
        function XTake(n, xf) {
            this.xf = xf;
            this.n = n;
        }
        XTake.prototype['@@transducer/init'] = _xfBase.init;
        XTake.prototype['@@transducer/result'] = _xfBase.result;
        XTake.prototype['@@transducer/step'] = function (result, input) {
            this.n -= 1;
            return this.n === 0 ? _reduced(this.xf['@@transducer/step'](result, input)) : this.xf['@@transducer/step'](result, input);
        };
        return _curry2(function _xtake(n, xf) {
            return new XTake(n, xf);
        });
    }();

    var _xtakeWhile = function () {
        function XTakeWhile(f, xf) {
            this.xf = xf;
            this.f = f;
        }
        XTakeWhile.prototype['@@transducer/init'] = _xfBase.init;
        XTakeWhile.prototype['@@transducer/result'] = _xfBase.result;
        XTakeWhile.prototype['@@transducer/step'] = function (result, input) {
            return this.f(input) ? this.xf['@@transducer/step'](result, input) : _reduced(result);
        };
        return _curry2(function _xtakeWhile(f, xf) {
            return new XTakeWhile(f, xf);
        });
    }();

    var _xwrap = function () {
        function XWrap(fn) {
            this.f = fn;
        }
        XWrap.prototype['@@transducer/init'] = function () {
            throw new Error('init not implemented on XWrap');
        };
        XWrap.prototype['@@transducer/result'] = function (acc) {
            return acc;
        };
        XWrap.prototype['@@transducer/step'] = function (acc, x) {
            return this.f(acc, x);
        };
        return function _xwrap(fn) {
            return new XWrap(fn);
        };
    }();

    /**
     * Adds two numbers (or strings). Equivalent to `a + b` but curried.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Number
     * @sig String -> String -> String
     * @param {Number|String} a The first value.
     * @param {Number|String} b The second value.
     * @return {Number|String} The result of `a + b`.
     * @example
     *
     *      R.add(2, 3);       //=>  5
     *      R.add(7)(10);      //=> 17
     */
    var add = _curry2(_add);

    /**
     * Applies a function to the value at the given index of an array,
     * returning a new copy of the array with the element at the given
     * index replaced with the result of the function application.
     * @see R.update
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> a) -> Number -> [a] -> [a]
     * @param {Function} fn The function to apply.
     * @param {Number} idx The index.
     * @param {Array|Arguments} list An array-like object whose value
     *        at the supplied index will be replaced.
     * @return {Array} A copy of the supplied array-like object with
     *         the element at index `idx` replaced with the value
     *         returned by applying `fn` to the existing element.
     * @example
     *
     *      R.adjust(R.add(10), 1, [0, 1, 2]);     //=> [0, 11, 2]
     *      R.adjust(R.add(10))(1)([0, 1, 2]);     //=> [0, 11, 2]
     */
    var adjust = _curry3(function (fn, idx, list) {
        if (idx >= list.length || idx < -list.length) {
            return list;
        }
        var start = idx < 0 ? list.length : 0;
        var _idx = start + idx;
        var _list = _concat(list);
        _list[_idx] = fn(list[_idx]);
        return _list;
    });

    /**
     * Returns a function that always returns the given value. Note that for non-primitives the value
     * returned is a reference to the original value.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig a -> (* -> a)
     * @param {*} val The value to wrap in a function
     * @return {Function} A Function :: * -> val.
     * @example
     *
     *      var t = R.always('Tee');
     *      t(); //=> 'Tee'
     */
    var always = _curry1(function always(val) {
        return function () {
            return val;
        };
    });

    /**
     * Returns a new list, composed of n-tuples of consecutive elements
     * If `n` is greater than the length of the list, an empty list is returned.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> [a] -> [[a]]
     * @param {Number} n The size of the tuples to create
     * @param {Array} list The list to split into `n`-tuples
     * @return {Array} The new list.
     * @example
     *
     *      R.aperture(2, [1, 2, 3, 4, 5]); //=> [[1, 2], [2, 3], [3, 4], [4, 5]]
     *      R.aperture(3, [1, 2, 3, 4, 5]); //=> [[1, 2, 3], [2, 3, 4], [3, 4, 5]]
     *      R.aperture(7, [1, 2, 3, 4, 5]); //=> []
     */
    var aperture = _curry2(function aperture(n, list) {
        var idx = 0;
        var limit = list.length - (n - 1);
        var acc = new Array(limit >= 0 ? limit : 0);
        while (idx < limit) {
            acc[idx] = _slice(list, idx, idx + n);
            idx += 1;
        }
        return acc;
    });

    /**
     * Applies function `fn` to the argument list `args`. This is useful for
     * creating a fixed-arity function from a variadic function. `fn` should
     * be a bound function if context is significant.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (*... -> a) -> [*] -> a
     * @param {Function} fn
     * @param {Array} args
     * @return {*}
     * @example
     *
     *      var nums = [1, 2, 3, -99, 42, 6, 7];
     *      R.apply(Math.max, nums); //=> 42
     */
    var apply = _curry2(function apply(fn, args) {
        return fn.apply(this, args);
    });

    /**
     * Wraps a function of any arity (including nullary) in a function that accepts exactly `n`
     * parameters. Unlike `nAry`, which passes only `n` arguments to the wrapped function,
     * functions produced by `arity` will pass all provided arguments to the wrapped function.
     *
     * @func
     * @memberOf R
     * @sig (Number, (* -> *)) -> (* -> *)
     * @category Function
     * @param {Number} n The desired arity of the returned function.
     * @param {Function} fn The function to wrap.
     * @return {Function} A new function wrapping `fn`. The new function is
     *         guaranteed to be of arity `n`.
     * @deprecated since v0.15.0
     * @example
     *
     *      var takesTwoArgs = function(a, b) {
     *        return [a, b];
     *      };
     *      takesTwoArgs.length; //=> 2
     *      takesTwoArgs(1, 2); //=> [1, 2]
     *
     *      var takesOneArg = R.arity(1, takesTwoArgs);
     *      takesOneArg.length; //=> 1
     *      // All arguments are passed through to the wrapped function
     *      takesOneArg(1, 2); //=> [1, 2]
     */
    // jshint unused:vars
    var arity = _curry2(function (n, fn) {
        // jshint unused:vars
        switch (n) {
        case 0:
            return function () {
                return fn.apply(this, arguments);
            };
        case 1:
            return function (a0) {
                return fn.apply(this, arguments);
            };
        case 2:
            return function (a0, a1) {
                return fn.apply(this, arguments);
            };
        case 3:
            return function (a0, a1, a2) {
                return fn.apply(this, arguments);
            };
        case 4:
            return function (a0, a1, a2, a3) {
                return fn.apply(this, arguments);
            };
        case 5:
            return function (a0, a1, a2, a3, a4) {
                return fn.apply(this, arguments);
            };
        case 6:
            return function (a0, a1, a2, a3, a4, a5) {
                return fn.apply(this, arguments);
            };
        case 7:
            return function (a0, a1, a2, a3, a4, a5, a6) {
                return fn.apply(this, arguments);
            };
        case 8:
            return function (a0, a1, a2, a3, a4, a5, a6, a7) {
                return fn.apply(this, arguments);
            };
        case 9:
            return function (a0, a1, a2, a3, a4, a5, a6, a7, a8) {
                return fn.apply(this, arguments);
            };
        case 10:
            return function (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) {
                return fn.apply(this, arguments);
            };
        default:
            throw new Error('First argument to arity must be a non-negative integer no greater than ten');
        }
    });

    /**
     * Makes a shallow clone of an object, setting or overriding the specified
     * property with the given value.  Note that this copies and flattens
     * prototype properties onto the new object as well.  All non-primitive
     * properties are copied by reference.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig String -> a -> {k: v} -> {k: v}
     * @param {String} prop the property name to set
     * @param {*} val the new value
     * @param {Object} obj the object to clone
     * @return {Object} a new object similar to the original except for the specified property.
     * @example
     *
     *      R.assoc('c', 3, {a: 1, b: 2}); //=> {a: 1, b: 2, c: 3}
     */
    var assoc = _curry3(_assoc);

    /**
     * Creates a function that is bound to a context.
     * Note: `R.bind` does not provide the additional argument-binding capabilities of
     * [Function.prototype.bind](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind).
     *
     * @func
     * @memberOf R
     * @category Function
     * @category Object
     * @see R.partial
     * @sig (* -> *) -> {*} -> (* -> *)
     * @param {Function} fn The function to bind to context
     * @param {Object} thisObj The context to bind `fn` to
     * @return {Function} A function that will execute in the context of `thisObj`.
     */
    var bind = _curry2(function bind(fn, thisObj) {
        return arity(fn.length, function () {
            return fn.apply(thisObj, arguments);
        });
    });

    /**
     * A function wrapping calls to the two functions in an `&&` operation, returning the result of the first
     * function if it is false-y and the result of the second function otherwise.  Note that this is
     * short-circuited, meaning that the second function will not be invoked if the first returns a false-y
     * value.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig (*... -> Boolean) -> (*... -> Boolean) -> (*... -> Boolean)
     * @param {Function} f a predicate
     * @param {Function} g another predicate
     * @return {Function} a function that applies its arguments to `f` and `g` and `&&`s their outputs together.
     * @example
     *
     *      var gt10 = function(x) { return x > 10; };
     *      var even = function(x) { return x % 2 === 0 };
     *      var f = R.both(gt10, even);
     *      f(100); //=> true
     *      f(101); //=> false
     */
    var both = _curry2(function both(f, g) {
        return function _both() {
            return f.apply(this, arguments) && g.apply(this, arguments);
        };
    });

    /**
     * Makes a comparator function out of a function that reports whether the first element is less than the second.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (a, b -> Boolean) -> (a, b -> Number)
     * @param {Function} pred A predicate function of arity two.
     * @return {Function} A Function :: a -> b -> Int that returns `-1` if a < b, `1` if b < a, otherwise `0`.
     * @example
     *
     *      var cmp = R.comparator(function(a, b) {
     *        return a.age < b.age;
     *      });
     *      var people = [
     *        // ...
     *      ];
     *      R.sort(cmp, people);
     */
    var comparator = _curry1(function comparator(pred) {
        return function (a, b) {
            return pred(a, b) ? -1 : pred(b, a) ? 1 : 0;
        };
    });

    /**
     * Takes a function `f` and returns a function `g` such that:
     *
     *   - applying `g` to zero or more arguments will give __true__ if applying
     *     the same arguments to `f` gives a logical __false__ value; and
     *
     *   - applying `g` to zero or more arguments will give __false__ if applying
     *     the same arguments to `f` gives a logical __true__ value.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig (*... -> *) -> (*... -> Boolean)
     * @param {Function} f
     * @return {Function}
     * @example
     *
     *      var isEven = function(n) { return n % 2 === 0; };
     *      var isOdd = R.complement(isEven);
     *      isOdd(21); //=> true
     *      isOdd(42); //=> false
     */
    var complement = _curry1(_complement);

    /**
     * Returns a function, `fn`, which encapsulates if/else-if/else logic.
     * Each argument to `R.cond` is a [predicate, transform] pair. All of
     * the arguments to `fn` are applied to each of the predicates in turn
     * until one returns a "truthy" value, at which point `fn` returns the
     * result of applying its arguments to the corresponding transformer.
     * If none of the predicates matches, `fn` returns undefined.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig [(*... -> Boolean),(*... -> *)]... -> (*... -> *)
     * @param {...Function} functions
     * @return {Function}
     * @example
     *
     *      var fn = R.cond(
     *        [R.equals(0),   R.always('water freezes at 0°C')],
     *        [R.equals(100), R.always('water boils at 100°C')],
     *        [R.T,           function(temp) { return 'nothing special happens at ' + temp + '°C'; }]
     *      );
     *      fn(0); //=> 'water freezes at 0°C'
     *      fn(50); //=> 'nothing special happens at 50°C'
     *      fn(100); //=> 'water boils at 100°C'
     */
    var cond = function cond() {
        var pairs = arguments;
        return function () {
            var idx = 0;
            while (idx < pairs.length) {
                if (pairs[idx][0].apply(this, arguments)) {
                    return pairs[idx][1].apply(this, arguments);
                }
                idx += 1;
            }
        };
    };

    /**
     * Returns `true` if the `x` is found in the `list`, using `pred` as an
     * equality predicate for `x`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a, a -> Boolean) -> a -> [a] -> Boolean
     * @param {Function} pred A predicate used to test whether two items are equal.
     * @param {*} x The item to find
     * @param {Array} list The list to iterate over
     * @return {Boolean} `true` if `x` is in `list`, else `false`.
     * @example
     *
     *      var xs = [{x: 12}, {x: 11}, {x: 10}];
     *      R.containsWith(function(a, b) { return a.x === b.x; }, {x: 10}, xs); //=> true
     *      R.containsWith(function(a, b) { return a.x === b.x; }, {x: 1}, xs); //=> false
     */
    var containsWith = _curry3(_containsWith);

    /**
     * Counts the elements of a list according to how many match each value
     * of a key generated by the supplied function. Returns an object
     * mapping the keys produced by `fn` to the number of occurrences in
     * the list. Note that all keys are coerced to strings because of how
     * JavaScript objects work.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig (a -> String) -> [a] -> {*}
     * @param {Function} fn The function used to map values to keys.
     * @param {Array} list The list to count elements from.
     * @return {Object} An object mapping keys to number of occurrences in the list.
     * @example
     *
     *      var numbers = [1.0, 1.1, 1.2, 2.0, 3.0, 2.2];
     *      var letters = R.split('', 'abcABCaaaBBc');
     *      R.countBy(Math.floor)(numbers);    //=> {'1': 3, '2': 2, '3': 1}
     *      R.countBy(R.toLower)(letters);   //=> {'a': 5, 'b': 4, 'c': 3}
     */
    var countBy = _curry2(function countBy(fn, list) {
        var counts = {};
        var len = list.length;
        var idx = 0;
        while (idx < len) {
            var key = fn(list[idx]);
            counts[key] = (_has(key, counts) ? counts[key] : 0) + 1;
            idx += 1;
        }
        return counts;
    });

    /**
     * Creates an object containing a single key:value pair.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig String -> a -> {String:a}
     * @param {String} key
     * @param {*} val
     * @return {Object}
     * @example
     *
     *      var matchPhrases = R.compose(
     *        R.createMapEntry('must'),
     *        R.map(R.createMapEntry('match_phrase'))
     *      );
     *      matchPhrases(['foo', 'bar', 'baz']); //=> {must: [{match_phrase: 'foo'}, {match_phrase: 'bar'}, {match_phrase: 'baz'}]}
     */
    var createMapEntry = _curry2(_createMapEntry);

    /**
     * Decrements its argument.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number
     * @param {Number} n
     * @return {Number}
     * @example
     *
     *      R.dec(42); //=> 41
     */
    var dec = add(-1);

    /**
     * Returns the second argument if it is not null or undefined. If it is null
     * or undefined, the first (default) argument is returned.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig a -> b -> a | b
     * @param {a} val The default value.
     * @param {b} val The value to return if it is not null or undefined
     * @return {*} The the second value or the default value
     * @example
     *
     *      var defaultTo42 = defaultTo(42);
     *
     *      defaultTo42(null);  //=> 42
     *      defaultTo42(undefined);  //=> 42
     *      defaultTo42('Ramda');  //=> 'Ramda'
     */
    var defaultTo = _curry2(function defaultTo(d, v) {
        return v == null ? d : v;
    });

    /**
     * Finds the set (i.e. no duplicates) of all elements in the first list not contained in the second list.
     * Duplication is determined according to the value returned by applying the supplied predicate to two list
     * elements.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig (a,a -> Boolean) -> [a] -> [a] -> [a]
     * @param {Function} pred A predicate used to test whether two items are equal.
     * @param {Array} list1 The first list.
     * @param {Array} list2 The second list.
     * @see R.difference
     * @return {Array} The elements in `list1` that are not in `list2`.
     * @example
     *
     *      function cmp(x, y) { return x.a === y.a; }
     *      var l1 = [{a: 1}, {a: 2}, {a: 3}];
     *      var l2 = [{a: 3}, {a: 4}];
     *      R.differenceWith(cmp, l1, l2); //=> [{a: 1}, {a: 2}]
     */
    var differenceWith = _curry3(function differenceWith(pred, first, second) {
        var out = [];
        var idx = 0;
        var firstLen = first.length;
        var containsPred = containsWith(pred);
        while (idx < firstLen) {
            if (!containsPred(first[idx], second) && !containsPred(first[idx], out)) {
                out[out.length] = first[idx];
            }
            idx += 1;
        }
        return out;
    });

    /**
     * Returns a new object that does not contain a `prop` property.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig String -> {k: v} -> {k: v}
     * @param {String} prop the name of the property to dissociate
     * @param {Object} obj the object to clone
     * @return {Object} a new object similar to the original but without the specified property
     * @example
     *
     *      R.dissoc('b', {a: 1, b: 2, c: 3}); //=> {a: 1, c: 3}
     */
    var dissoc = _curry2(_dissoc);

    /**
     * Divides two numbers. Equivalent to `a / b`.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Number
     * @param {Number} a The first value.
     * @param {Number} b The second value.
     * @return {Number} The result of `a / b`.
     * @example
     *
     *      R.divide(71, 100); //=> 0.71
     *
     *      var half = R.divide(R.__, 2);
     *      half(42); //=> 21
     *
     *      var reciprocal = R.divide(1);
     *      reciprocal(4);   //=> 0.25
     */
    var divide = _curry2(function divide(a, b) {
        return a / b;
    });

    /**
     * A function wrapping calls to the two functions in an `||` operation, returning the result of the first
     * function if it is truth-y and the result of the second function otherwise.  Note that this is
     * short-circuited, meaning that the second function will not be invoked if the first returns a truth-y
     * value.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig (*... -> Boolean) -> (*... -> Boolean) -> (*... -> Boolean)
     * @param {Function} f a predicate
     * @param {Function} g another predicate
     * @return {Function} a function that applies its arguments to `f` and `g` and `||`s their outputs together.
     * @example
     *
     *      var gt10 = function(x) { return x > 10; };
     *      var even = function(x) { return x % 2 === 0 };
     *      var f = R.either(gt10, even);
     *      f(101); //=> true
     *      f(8); //=> true
     */
    var either = _curry2(function either(f, g) {
        return function _either() {
            return f.apply(this, arguments) || g.apply(this, arguments);
        };
    });

    /**
     * Tests if two items are equal.  Equality is strict here, meaning reference equality for objects and
     * non-coercing equality for primitives.
     *
     * Has `Object.is` semantics: `NaN` is considered equal to `NaN`; `0` and `-0`
     * are not considered equal.
     * @see R.identical
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig a -> a -> Boolean
     * @param {*} a
     * @param {*} b
     * @return {Boolean}
     * @deprecated since v0.15.0
     * @example
     *
     *      var o = {};
     *      R.eq(o, o); //=> true
     *      R.eq(o, {}); //=> false
     *      R.eq(1, 1); //=> true
     *      R.eq(1, '1'); //=> false
     *      R.eq(0, -0); //=> false
     *      R.eq(NaN, NaN); //=> true
     */
    var eq = _curry2(_eq);

    /**
     * Creates a new object by recursively evolving a shallow copy of `object`, according to the
     * `transformation` functions. All non-primitive properties are copied by reference.
     *
     * A `tranformation` function will not be invoked if its corresponding key does not exist in
     * the evolved object.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {k: (v -> v)} -> {k: v} -> {k: v}
     * @param {Object} transformations The object specifying transformation functions to apply
     *        to the object.
     * @param {Object} object The object to be transformed.
     * @return {Object} The transformed object.
     * @example
     *
     *      var tomato  = {firstName: '  Tomato ', elapsed: 100, remaining: 1400};
     *      var transformations = {
     *        firstName: R.trim,
     *        lastName: R.trim, // Will not get invoked.
     *        data: {elapsed: R.add(1), remaining: R.add(-1)}
     *      };
     *      R.evolve(transformations, tomato); //=> {firstName: 'Tomato', data: {elapsed: 101, remaining: 1399}}
     */
    var evolve = _curry2(function evolve(transformations, object) {
        var transformation, key, type, result = {};
        for (key in object) {
            transformation = transformations[key];
            type = typeof transformation;
            result[key] = type === 'function' ? transformation(object[key]) : type === 'object' ? evolve(transformations[key], object[key]) : object[key];
        }
        return result;
    });

    /**
     * Like `filter`, but passes additional parameters to the predicate function. The predicate
     * function is passed three arguments: *(value, index, list)*.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a, i, [a] -> Boolean) -> [a] -> [a]
     * @param {Function} fn The function called per iteration.
     * @param {Array} list The collection to iterate over.
     * @return {Array} The new filtered array.
     * @deprecated since v0.15.0
     * @see R.addIndex
     * @example
     *
     *      var lastTwo = function(val, idx, list) {
     *        return list.length - idx <= 2;
     *      };
     *      R.filterIndexed(lastTwo, [8, 6, 7, 5, 3, 0, 9]); //=> [0, 9]
     */
    var filterIndexed = _curry2(_filterIndexed);

    /**
     * Like `forEach`, but but passes additional parameters to the predicate function.
     *
     * `fn` receives three arguments: *(value, index, list)*.
     *
     * Note: `R.forEachIndexed` does not skip deleted or unassigned indices (sparse arrays),
     * unlike the native `Array.prototype.forEach` method. For more details on this behavior,
     * see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach#Description
     *
     * Also note that, unlike `Array.prototype.forEach`, Ramda's `forEach` returns the original
     * array. In some libraries this function is named `each`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a, i, [a] -> ) -> [a] -> [a]
     * @param {Function} fn The function to invoke. Receives three arguments:
     *        (`value`, `index`, `list`).
     * @param {Array} list The list to iterate over.
     * @return {Array} The original list.
     * @deprecated since v0.15.0
     * @see R.addIndex
     * @example
     *
     *      // Note that having access to the original `list` allows for
     *      // mutation. While you *can* do this, it's very un-functional behavior:
     *      var plusFive = function(num, idx, list) { list[idx] = num + 5 };
     *      R.forEachIndexed(plusFive, [1, 2, 3]); //=> [6, 7, 8]
     */
    // i can't bear not to return *something*
    var forEachIndexed = _curry2(function forEachIndexed(fn, list) {
        var idx = 0, len = list.length;
        while (idx < len) {
            fn(list[idx], idx, list);
            idx += 1;
        }
        // i can't bear not to return *something*
        return list;
    });

    /**
     * Creates a new object out of a list key-value pairs.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [[k,v]] -> {k: v}
     * @param {Array} pairs An array of two-element arrays that will be the keys and values of the output object.
     * @return {Object} The object made by pairing up `keys` and `values`.
     * @example
     *
     *      R.fromPairs([['a', 1], ['b', 2],  ['c', 3]]); //=> {a: 1, b: 2, c: 3}
     */
    var fromPairs = _curry1(function fromPairs(pairs) {
        var idx = 0, len = pairs.length, out = {};
        while (idx < len) {
            if (_isArray(pairs[idx]) && pairs[idx].length) {
                out[pairs[idx][0]] = pairs[idx][1];
            }
            idx += 1;
        }
        return out;
    });

    /**
     * Returns true if the first parameter is greater than the second.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Boolean
     * @param {Number} a
     * @param {Number} b
     * @return {Boolean} a > b
     * @example
     *
     *      R.gt(2, 6); //=> false
     *      R.gt(2, 0); //=> true
     *      R.gt(2, 2); //=> false
     *      R.gt(R.__, 2)(10); //=> true
     *      R.gt(2)(10); //=> false
     */
    var gt = _curry2(_gt);

    /**
     * Returns true if the first parameter is greater than or equal to the second.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Boolean
     * @param {Number} a
     * @param {Number} b
     * @return {Boolean} a >= b
     * @example
     *
     *      R.gte(2, 6); //=> false
     *      R.gte(2, 0); //=> true
     *      R.gte(2, 2); //=> true
     *      R.gte(R.__, 6)(2); //=> false
     *      R.gte(2)(0); //=> true
     */
    var gte = _curry2(function gte(a, b) {
        return a >= b;
    });

    /**
     * Returns whether or not an object has an own property with
     * the specified name
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig s -> {s: x} -> Boolean
     * @param {String} prop The name of the property to check for.
     * @param {Object} obj The object to query.
     * @return {Boolean} Whether the property exists.
     * @example
     *
     *      var hasName = R.has('name');
     *      hasName({name: 'alice'});   //=> true
     *      hasName({name: 'bob'});     //=> true
     *      hasName({});                //=> false
     *
     *      var point = {x: 0, y: 0};
     *      var pointHas = R.has(R.__, point);
     *      pointHas('x');  //=> true
     *      pointHas('y');  //=> true
     *      pointHas('z');  //=> false
     */
    var has = _curry2(_has);

    /**
     * Returns whether or not an object or its prototype chain has
     * a property with the specified name
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig s -> {s: x} -> Boolean
     * @param {String} prop The name of the property to check for.
     * @param {Object} obj The object to query.
     * @return {Boolean} Whether the property exists.
     * @example
     *
     *      function Rectangle(width, height) {
     *        this.width = width;
     *        this.height = height;
     *      }
     *      Rectangle.prototype.area = function() {
     *        return this.width * this.height;
     *      };
     *
     *      var square = new Rectangle(2, 2);
     *      R.hasIn('width', square);  //=> true
     *      R.hasIn('area', square);  //=> true
     */
    var hasIn = _curry2(function (prop, obj) {
        return prop in obj;
    });

    /**
     * Returns true if its arguments are identical, false otherwise. Values are
     * identical if they reference the same memory. `NaN` is identical to `NaN`;
     * `0` and `-0` are not identical.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig a -> a -> Boolean
     * @param {*} a
     * @param {*} b
     * @return {Boolean}
     * @example
     *
     *      var o = {};
     *      R.identical(o, o); //=> true
     *      R.identical(1, 1); //=> true
     *      R.identical(1, '1'); //=> false
     *      R.identical([], []); //=> false
     *      R.identical(0, -0); //=> false
     *      R.identical(NaN, NaN); //=> true
     */
    // SameValue algorithm
    // Steps 1-5, 7-10
    // Steps 6.b-6.e: +0 != -0
    // Step 6.a: NaN == NaN
    var identical = _curry2(function identical(a, b) {
        // SameValue algorithm
        if (a === b) {
            // Steps 1-5, 7-10
            // Steps 6.b-6.e: +0 != -0
            return a !== 0 || 1 / a === 1 / b;
        } else {
            // Step 6.a: NaN == NaN
            return a !== a && b !== b;
        }
    });

    /**
     * A function that does nothing but return the parameter supplied to it. Good as a default
     * or placeholder function.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig a -> a
     * @param {*} x The value to return.
     * @return {*} The input value, `x`.
     * @example
     *
     *      R.identity(1); //=> 1
     *
     *      var obj = {};
     *      R.identity(obj) === obj; //=> true
     */
    var identity = _curry1(_identity);

    /**
     * Increments its argument.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number
     * @param {Number} n
     * @return {Number}
     * @example
     *
     *      R.inc(42); //=> 43
     */
    var inc = add(1);

    /**
     * Inserts the sub-list into the list, at index `index`.  _Note  that this
     * is not destructive_: it returns a copy of the list with the changes.
     * <small>No lists have been harmed in the application of this function.</small>
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> [a] -> [a] -> [a]
     * @param {Number} index The position to insert the sub-list
     * @param {Array} elts The sub-list to insert into the Array
     * @param {Array} list The list to insert the sub-list into
     * @return {Array} A new Array with `elts` inserted starting at `index`.
     * @example
     *
     *      R.insertAll(2, ['x','y','z'], [1,2,3,4]); //=> [1,2,'x','y','z',3,4]
     */
    var insertAll = _curry3(function insertAll(idx, elts, list) {
        idx = idx < list.length && idx >= 0 ? idx : list.length;
        return _concat(_concat(_slice(list, 0, idx), elts), _slice(list, idx));
    });

    /**
     * See if an object (`val`) is an instance of the supplied constructor.
     * This function will check up the inheritance chain, if any.
     *
     * @func
     * @memberOf R
     * @category Type
     * @sig (* -> {*}) -> a -> Boolean
     * @param {Object} ctor A constructor
     * @param {*} val The value to test
     * @return {Boolean}
     * @example
     *
     *      R.is(Object, {}); //=> true
     *      R.is(Number, 1); //=> true
     *      R.is(Object, 1); //=> false
     *      R.is(String, 's'); //=> true
     *      R.is(String, new String('')); //=> true
     *      R.is(Object, new String('')); //=> true
     *      R.is(Object, 's'); //=> false
     *      R.is(Number, {}); //=> false
     */
    var is = _curry2(function is(Ctor, val) {
        return val != null && val.constructor === Ctor || val instanceof Ctor;
    });

    /**
     * Tests whether or not an object is similar to an array.
     *
     * @func
     * @memberOf R
     * @category Type
     * @category List
     * @sig * -> Boolean
     * @param {*} x The object to test.
     * @return {Boolean} `true` if `x` has a numeric length property and extreme indices defined; `false` otherwise.
     * @example
     *
     *      R.isArrayLike([]); //=> true
     *      R.isArrayLike(true); //=> false
     *      R.isArrayLike({}); //=> false
     *      R.isArrayLike({length: 10}); //=> false
     *      R.isArrayLike({0: 'zero', 9: 'nine', length: 10}); //=> true
     */
    var isArrayLike = _curry1(function isArrayLike(x) {
        if (_isArray(x)) {
            return true;
        }
        if (!x) {
            return false;
        }
        if (typeof x !== 'object') {
            return false;
        }
        if (x instanceof String) {
            return false;
        }
        if (x.nodeType === 1) {
            return !!x.length;
        }
        if (x.length === 0) {
            return true;
        }
        if (x.length > 0) {
            return x.hasOwnProperty(0) && x.hasOwnProperty(x.length - 1);
        }
        return false;
    });

    /**
     * Reports whether the list has zero elements.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig [a] -> Boolean
     * @param {Array} list
     * @return {Boolean}
     * @example
     *
     *      R.isEmpty([1, 2, 3]);   //=> false
     *      R.isEmpty([]);          //=> true
     *      R.isEmpty('');          //=> true
     *      R.isEmpty(null);        //=> false
     *      R.isEmpty(R.keys({}));  //=> true
     *      R.isEmpty({});          //=> false ({} does not have a length property)
     *      R.isEmpty({length: 0}); //=> true
     */
    var isEmpty = _curry1(function isEmpty(list) {
        return Object(list).length === 0;
    });

    /**
     * Checks if the input value is `null` or `undefined`.
     *
     * @func
     * @memberOf R
     * @category Type
     * @sig * -> Boolean
     * @param {*} x The value to test.
     * @return {Boolean} `true` if `x` is `undefined` or `null`, otherwise `false`.
     * @example
     *
     *      R.isNil(null); //=> true
     *      R.isNil(undefined); //=> true
     *      R.isNil(0); //=> false
     *      R.isNil([]); //=> false
     */
    var isNil = _curry1(function isNil(x) {
        return x == null;
    });

    /**
     * Returns a list containing the names of all the enumerable own
     * properties of the supplied object.
     * Note that the order of the output array is not guaranteed to be
     * consistent across different JS platforms.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {k: v} -> [k]
     * @param {Object} obj The object to extract properties from
     * @return {Array} An array of the object's own properties.
     * @example
     *
     *      R.keys({a: 1, b: 2, c: 3}); //=> ['a', 'b', 'c']
     */
    // cover IE < 9 keys issues
    var keys = function () {
        // cover IE < 9 keys issues
        var hasEnumBug = !{ toString: null }.propertyIsEnumerable('toString');
        var nonEnumerableProps = [
            'constructor',
            'valueOf',
            'isPrototypeOf',
            'toString',
            'propertyIsEnumerable',
            'hasOwnProperty',
            'toLocaleString'
        ];
        var contains = function contains(list, item) {
            var idx = 0;
            while (idx < list.length) {
                if (list[idx] === item) {
                    return true;
                }
                idx += 1;
            }
            return false;
        };
        return typeof Object.keys === 'function' ? _curry1(function keys(obj) {
            return Object(obj) !== obj ? [] : Object.keys(obj);
        }) : _curry1(function keys(obj) {
            if (Object(obj) !== obj) {
                return [];
            }
            var prop, ks = [], nIdx;
            for (prop in obj) {
                if (_has(prop, obj)) {
                    ks[ks.length] = prop;
                }
            }
            if (hasEnumBug) {
                nIdx = nonEnumerableProps.length - 1;
                while (nIdx >= 0) {
                    prop = nonEnumerableProps[nIdx];
                    if (_has(prop, obj) && !contains(ks, prop)) {
                        ks[ks.length] = prop;
                    }
                    nIdx -= 1;
                }
            }
            return ks;
        });
    }();

    /**
     * Returns a list containing the names of all the
     * properties of the supplied object, including prototype properties.
     * Note that the order of the output array is not guaranteed to be
     * consistent across different JS platforms.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {k: v} -> [k]
     * @param {Object} obj The object to extract properties from
     * @return {Array} An array of the object's own and prototype properties.
     * @example
     *
     *      var F = function() { this.x = 'X'; };
     *      F.prototype.y = 'Y';
     *      var f = new F();
     *      R.keysIn(f); //=> ['x', 'y']
     */
    var keysIn = _curry1(function keysIn(obj) {
        var prop, ks = [];
        for (prop in obj) {
            ks[ks.length] = prop;
        }
        return ks;
    });

    /**
     * Returns the number of elements in the array by returning `list.length`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> Number
     * @param {Array} list The array to inspect.
     * @return {Number} The length of the array.
     * @example
     *
     *      R.length([]); //=> 0
     *      R.length([1, 2, 3]); //=> 3
     */
    var length = _curry1(function length(list) {
        return list != null && is(Number, list.length) ? list.length : NaN;
    });

    /**
     * Creates a lens. Supply a function to `get` values from inside an object, and a `set`
     * function to change values on an object. (n.b.: This can, and should, be done without
     * mutating the original object!) The lens is a function wrapped around the input `get`
     * function, with the `set` function attached as a property on the wrapper. A `map`
     * function is also attached to the returned function that takes a function to operate
     * on the specified (`get`) property, which is then `set` before returning. The attached
     * `set` and `map` functions are curried.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig (k -> v) -> (v -> a -> *) -> (a -> b)
     * @param {Function} get A function that gets a value by property name
     * @param {Function} set A function that sets a value by property name
     * @return {Function} the returned function has `set` and `map` properties that are
     *         also curried functions.
     * @example
     *
     *      var headLens = R.lens(
     *        function get(arr) { return arr[0]; },
     *        function set(val, arr) { return [val].concat(arr.slice(1)); }
     *      );
     *      headLens([10, 20, 30, 40]); //=> 10
     *      headLens.set('mu', [10, 20, 30, 40]); //=> ['mu', 20, 30, 40]
     *      headLens.map(function(x) { return x + 1; }, [10, 20, 30, 40]); //=> [11, 20, 30, 40]
     *
     *      var phraseLens = R.lens(
     *        function get(obj) { return obj.phrase; },
     *        function set(val, obj) {
     *          var out = R.clone(obj);
     *          out.phrase = val;
     *          return out;
     *        }
     *      );
     *      var obj1 = { phrase: 'Absolute filth . . . and I LOVED it!'};
     *      var obj2 = { phrase: "What's all this, then?"};
     *      phraseLens(obj1); // => 'Absolute filth . . . and I LOVED it!'
     *      phraseLens(obj2); // => "What's all this, then?"
     *      phraseLens.set('Ooh Betty', obj1); //=> { phrase: 'Ooh Betty'}
     *      phraseLens.map(R.toUpper, obj2); //=> { phrase: "WHAT'S ALL THIS, THEN?"}
     */
    var lens = _curry2(function lens(get, set) {
        var lns = function (a) {
            return get(a);
        };
        lns.set = _curry2(set);
        lns.map = _curry2(function (fn, a) {
            return set(fn(get(a)), a);
        });
        return lns;
    });

    /**
     * Returns a lens associated with the provided object.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig ({} -> v) -> (v -> a -> *) -> {} -> (a -> b)
     * @see R.lens
     * @param {Function} get A function that gets a value by property name
     * @param {Function} set A function that sets a value by property name
     * @param {Object} the actual object of interest
     * @return {Function} the returned function has `set` and `map` properties that are
     *         also curried functions.
     * @example
     *
     *      var xo = {x: 1};
     *      var xoLens = R.lensOn(function get(o) { return o.x; },
     *                            function set(v) { return {x: v}; },
     *                            xo);
     *      xoLens(); //=> 1
     *      xoLens.set(1000); //=> {x: 1000}
     *      xoLens.map(R.add(1)); //=> {x: 2}
     */
    var lensOn = _curry3(function lensOn(get, set, obj) {
        var lns = function () {
            return get(obj);
        };
        lns.set = set;
        lns.map = function (fn) {
            return set(fn(get(obj)));
        };
        return lns;
    });

    /**
     * Returns true if the first parameter is less than the second.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Boolean
     * @param {Number} a
     * @param {Number} b
     * @return {Boolean} a < b
     * @example
     *
     *      R.lt(2, 6); //=> true
     *      R.lt(2, 0); //=> false
     *      R.lt(2, 2); //=> false
     *      R.lt(5)(10); //=> true
     *      R.lt(R.__, 5)(10); //=> false // right-sectioned currying
     */
    var lt = _curry2(_lt);

    /**
     * Returns true if the first parameter is less than or equal to the second.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Boolean
     * @param {Number} a
     * @param {Number} b
     * @return {Boolean} a <= b
     * @example
     *
     *      R.lte(2, 6); //=> true
     *      R.lte(2, 0); //=> false
     *      R.lte(2, 2); //=> true
     *      R.lte(R.__, 2)(1); //=> true
     *      R.lte(2)(10); //=> true
     */
    var lte = _curry2(function lte(a, b) {
        return a <= b;
    });

    /**
     * The mapAccum function behaves like a combination of map and reduce; it applies a
     * function to each element of a list, passing an accumulating parameter from left to
     * right, and returning a final value of this accumulator together with the new list.
     *
     * The iterator function receives two arguments, *acc* and *value*, and should return
     * a tuple *[acc, value]*.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
     * @param {Function} fn The function to be called on every element of the input `list`.
     * @param {*} acc The accumulator value.
     * @param {Array} list The list to iterate over.
     * @return {*} The final, accumulated value.
     * @example
     *
     *      var digits = ['1', '2', '3', '4'];
     *      var append = function(a, b) {
     *        return [a + b, a + b];
     *      }
     *
     *      R.mapAccum(append, 0, digits); //=> ['01234', ['01', '012', '0123', '01234']]
     */
    var mapAccum = _curry3(function mapAccum(fn, acc, list) {
        var idx = 0, len = list.length, result = [], tuple = [acc];
        while (idx < len) {
            tuple = fn(tuple[0], list[idx]);
            result[idx] = tuple[1];
            idx += 1;
        }
        return [
            tuple[0],
            result
        ];
    });

    /**
     * The mapAccumRight function behaves like a combination of map and reduce; it applies a
     * function to each element of a list, passing an accumulating parameter from right
     * to left, and returning a final value of this accumulator together with the new list.
     *
     * Similar to `mapAccum`, except moves through the input list from the right to the
     * left.
     *
     * The iterator function receives two arguments, *acc* and *value*, and should return
     * a tuple *[acc, value]*.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
     * @param {Function} fn The function to be called on every element of the input `list`.
     * @param {*} acc The accumulator value.
     * @param {Array} list The list to iterate over.
     * @return {*} The final, accumulated value.
     * @example
     *
     *      var digits = ['1', '2', '3', '4'];
     *      var append = function(a, b) {
     *        return [a + b, a + b];
     *      }
     *
     *      R.mapAccumRight(append, 0, digits); //=> ['04321', ['04321', '0432', '043', '04']]
     */
    var mapAccumRight = _curry3(function mapAccumRight(fn, acc, list) {
        var idx = list.length - 1, result = [], tuple = [acc];
        while (idx >= 0) {
            tuple = fn(tuple[0], list[idx]);
            result[idx] = tuple[1];
            idx -= 1;
        }
        return [
            tuple[0],
            result
        ];
    });

    /**
     * Like `map`, but but passes additional parameters to the mapping function.
     * `fn` receives three arguments: *(value, index, list)*.
     *
     * Note: `R.mapIndexed` does not skip deleted or unassigned indices (sparse arrays), unlike
     * the native `Array.prototype.map` method. For more details on this behavior, see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map#Description
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a,i,[b] -> b) -> [a] -> [b]
     * @param {Function} fn The function to be called on every element of the input `list`.
     * @param {Array} list The list to be iterated over.
     * @return {Array} The new list.
     * @deprecated since v0.15.0
     * @see R.addIndex
     * @example
     *
     *      var squareEnds = function(elt, idx, list) {
     *        if (idx === 0 || idx === list.length - 1) {
     *          return elt * elt;
     *        }
     *        return elt;
     *      };
     *
     *      R.mapIndexed(squareEnds, [8, 5, 3, 0, 9]); //=> [64, 5, 3, 0, 81]
     */
    var mapIndexed = _curry2(function mapIndexed(fn, list) {
        var idx = 0, len = list.length, result = [];
        while (idx < len) {
            result[idx] = fn(list[idx], idx, list);
            idx += 1;
        }
        return result;
    });

    /**
     * mathMod behaves like the modulo operator should mathematically, unlike the `%`
     * operator (and by extension, R.modulo). So while "-17 % 5" is -2,
     * mathMod(-17, 5) is 3. mathMod requires Integer arguments, and returns NaN
     * when the modulus is zero or negative.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Number
     * @param {Number} m The dividend.
     * @param {Number} p the modulus.
     * @return {Number} The result of `b mod a`.
     * @see R.moduloBy
     * @example
     *
     *      R.mathMod(-17, 5);  //=> 3
     *      R.mathMod(17, 5);   //=> 2
     *      R.mathMod(17, -5);  //=> NaN
     *      R.mathMod(17, 0);   //=> NaN
     *      R.mathMod(17.2, 5); //=> NaN
     *      R.mathMod(17, 5.3); //=> NaN
     *
     *      var clock = R.mathMod(R.__, 12);
     *      clock(15); //=> 3
     *      clock(24); //=> 0
     *
     *      var seventeenMod = R.mathMod(17);
     *      seventeenMod(3);  //=> 2
     *      seventeenMod(4);  //=> 1
     *      seventeenMod(10); //=> 7
     */
    var mathMod = _curry2(function mathMod(m, p) {
        if (!_isInteger(m)) {
            return NaN;
        }
        if (!_isInteger(p) || p < 1) {
            return NaN;
        }
        return (m % p + p) % p;
    });

    /**
     * Determines the largest of a list of items as determined by pairwise comparisons from the supplied comparator.
     * Note that this will return undefined if supplied an empty list.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig (a -> Number) -> [a] -> a
     * @param {Function} keyFn A comparator function for elements in the list
     * @param {Array} list A list of comparable elements
     * @return {*} The greatest element in the list. `undefined` if the list is empty.
     * @see R.max
     * @example
     *
     *      function cmp(obj) { return obj.x; }
     *      var a = {x: 1}, b = {x: 2}, c = {x: 3};
     *      R.maxBy(cmp, [a, b, c]); //=> {x: 3}
     */
    var maxBy = _curry2(_createMaxMinBy(_gt));

    /**
     * Determines the smallest of a list of items as determined by pairwise comparisons from the supplied comparator
     * Note that this will return undefined if supplied an empty list.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig (a -> Number) -> [a] -> a
     * @param {Function} keyFn A comparator function for elements in the list
     * @param {Array} list A list of comparable elements
     * @see R.min
     * @return {*} The greatest element in the list. `undefined` if the list is empty.
     * @example
     *
     *      function cmp(obj) { return obj.x; }
     *      var a = {x: 1}, b = {x: 2}, c = {x: 3};
     *      R.minBy(cmp, [a, b, c]); //=> {x: 1}
     */
    var minBy = _curry2(_createMaxMinBy(_lt));

    /**
     * Divides the second parameter by the first and returns the remainder.
     * Note that this functions preserves the JavaScript-style behavior for
     * modulo. For mathematical modulo see `mathMod`
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Number
     * @param {Number} a The value to the divide.
     * @param {Number} b The pseudo-modulus
     * @return {Number} The result of `b % a`.
     * @see R.mathMod
     * @example
     *
     *      R.modulo(17, 3); //=> 2
     *      // JS behavior:
     *      R.modulo(-17, 3); //=> -2
     *      R.modulo(17, -3); //=> 2
     *
     *      var isOdd = R.modulo(R.__, 2);
     *      isOdd(42); //=> 0
     *      isOdd(21); //=> 1
     */
    var modulo = _curry2(function modulo(a, b) {
        return a % b;
    });

    /**
     * Multiplies two numbers. Equivalent to `a * b` but curried.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Number
     * @param {Number} a The first value.
     * @param {Number} b The second value.
     * @return {Number} The result of `a * b`.
     * @example
     *
     *      var double = R.multiply(2);
     *      var triple = R.multiply(3);
     *      double(3);       //=>  6
     *      triple(4);       //=> 12
     *      R.multiply(2, 5);  //=> 10
     */
    var multiply = _curry2(_multiply);

    /**
     * Wraps a function of any arity (including nullary) in a function that accepts exactly `n`
     * parameters. Any extraneous parameters will not be passed to the supplied function.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig Number -> (* -> a) -> (* -> a)
     * @param {Number} n The desired arity of the new function.
     * @param {Function} fn The function to wrap.
     * @return {Function} A new function wrapping `fn`. The new function is guaranteed to be of
     *         arity `n`.
     * @example
     *
     *      var takesTwoArgs = function(a, b) {
     *        return [a, b];
     *      };
     *      takesTwoArgs.length; //=> 2
     *      takesTwoArgs(1, 2); //=> [1, 2]
     *
     *      var takesOneArg = R.nAry(1, takesTwoArgs);
     *      takesOneArg.length; //=> 1
     *      // Only `n` arguments are passed to the wrapped function
     *      takesOneArg(1, 2); //=> [1, undefined]
     */
    var nAry = _curry2(function (n, fn) {
        switch (n) {
        case 0:
            return function () {
                return fn.call(this);
            };
        case 1:
            return function (a0) {
                return fn.call(this, a0);
            };
        case 2:
            return function (a0, a1) {
                return fn.call(this, a0, a1);
            };
        case 3:
            return function (a0, a1, a2) {
                return fn.call(this, a0, a1, a2);
            };
        case 4:
            return function (a0, a1, a2, a3) {
                return fn.call(this, a0, a1, a2, a3);
            };
        case 5:
            return function (a0, a1, a2, a3, a4) {
                return fn.call(this, a0, a1, a2, a3, a4);
            };
        case 6:
            return function (a0, a1, a2, a3, a4, a5) {
                return fn.call(this, a0, a1, a2, a3, a4, a5);
            };
        case 7:
            return function (a0, a1, a2, a3, a4, a5, a6) {
                return fn.call(this, a0, a1, a2, a3, a4, a5, a6);
            };
        case 8:
            return function (a0, a1, a2, a3, a4, a5, a6, a7) {
                return fn.call(this, a0, a1, a2, a3, a4, a5, a6, a7);
            };
        case 9:
            return function (a0, a1, a2, a3, a4, a5, a6, a7, a8) {
                return fn.call(this, a0, a1, a2, a3, a4, a5, a6, a7, a8);
            };
        case 10:
            return function (a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) {
                return fn.call(this, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9);
            };
        default:
            throw new Error('First argument to nAry must be a non-negative integer no greater than ten');
        }
    });

    /**
     * Negates its argument.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number
     * @param {Number} n
     * @return {Number}
     * @example
     *
     *      R.negate(42); //=> -42
     */
    var negate = _curry1(function negate(n) {
        return -n;
    });

    /**
     * A function that returns the `!` of its argument. It will return `true` when
     * passed false-y value, and `false` when passed a truth-y one.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig * -> Boolean
     * @param {*} a any value
     * @return {Boolean} the logical inverse of passed argument.
     * @see R.complement
     * @example
     *
     *      R.not(true); //=> false
     *      R.not(false); //=> true
     *      R.not(0); => true
     *      R.not(1); => false
     */
    var not = _curry1(function not(a) {
        return !a;
    });

    /**
     * Returns the nth element in a list.
     * If n is negative the element at index length + n is returned.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> [a] -> a
     * @param {Number} idx
     * @param {Array} list
     * @return {*} The nth element of the list.
     * @example
     *
     *      var list = ['foo', 'bar', 'baz', 'quux'];
     *      R.nth(1, list); //=> 'bar'
     *      R.nth(-1, list); //=> 'quux'
     *      R.nth(-99, list); //=> undefined
     */
    var nth = _curry2(_nth);

    /**
     * Returns a function which returns its nth argument.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig Number -> *... -> *
     * @param {Number} n
     * @return {Function}
     * @example
     *
     *      R.nthArg(1)('a', 'b', 'c'); //=> 'b'
     *      R.nthArg(-1)('a', 'b', 'c'); //=> 'c'
     */
    var nthArg = _curry1(function nthArg(n) {
        return function () {
            return _nth(n, arguments);
        };
    });

    /**
     * Returns the nth character of the given string.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig Number -> String -> String
     * @param {Number} n
     * @param {String} str
     * @return {String}
     * @example
     *
     *      R.nthChar(2, 'Ramda'); //=> 'm'
     *      R.nthChar(-2, 'Ramda'); //=> 'd'
     */
    var nthChar = _curry2(function nthChar(n, str) {
        return str.charAt(n < 0 ? str.length + n : n);
    });

    /**
     * Returns the character code of the nth character of the given string.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig Number -> String -> Number
     * @param {Number} n
     * @param {String} str
     * @return {Number}
     * @example
     *
     *      R.nthCharCode(2, 'Ramda'); //=> 'm'.charCodeAt(0)
     *      R.nthCharCode(-2, 'Ramda'); //=> 'd'.charCodeAt(0)
     */
    var nthCharCode = _curry2(function nthCharCode(n, str) {
        return str.charCodeAt(n < 0 ? str.length + n : n);
    });

    /**
     * Returns a singleton array containing the value provided.
     *
     * Note this `of` is different from the ES6 `of`; See
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/of
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig a -> [a]
     * @param {*} x any value
     * @return {Array} An array wrapping `x`.
     * @example
     *
     *      R.of(null); //=> [null]
     *      R.of([42]); //=> [[42]]
     */
    var of = _curry1(function of(x) {
        return [x];
    });

    /**
     * Accepts a function `fn` and returns a function that guards invocation of `fn` such that
     * `fn` can only ever be called once, no matter how many times the returned function is
     * invoked.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (a... -> b) -> (a... -> b)
     * @param {Function} fn The function to wrap in a call-only-once wrapper.
     * @return {Function} The wrapped function.
     * @example
     *
     *      var addOneOnce = R.once(function(x){ return x + 1; });
     *      addOneOnce(10); //=> 11
     *      addOneOnce(addOneOnce(50)); //=> 11
     */
    var once = _curry1(function once(fn) {
        var called = false, result;
        return function () {
            if (called) {
                return result;
            }
            called = true;
            result = fn.apply(this, arguments);
            return result;
        };
    });

    /**
     * Retrieve the value at a given path.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig [String] -> {*} -> *
     * @param {Array} path The path to use.
     * @return {*} The data at `path`.
     * @example
     *
     *      R.path(['a', 'b'], {a: {b: 2}}); //=> 2
     */
    var path = _curry2(_path);

    /**
     * Returns a partial copy of an object containing only the keys specified.  If the key does not exist, the
     * property is ignored.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig [k] -> {k: v} -> {k: v}
     * @param {Array} names an array of String property names to copy onto a new object
     * @param {Object} obj The object to copy from
     * @return {Object} A new object with only properties from `names` on it.
     * @example
     *
     *      R.pick(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, d: 4}
     *      R.pick(['a', 'e', 'f'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1}
     */
    var pick = _curry2(function pick(names, obj) {
        var result = {};
        var idx = 0;
        while (idx < names.length) {
            if (names[idx] in obj) {
                result[names[idx]] = obj[names[idx]];
            }
            idx += 1;
        }
        return result;
    });

    /**
     * Similar to `pick` except that this one includes a `key: undefined` pair for properties that don't exist.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig [k] -> {k: v} -> {k: v}
     * @param {Array} names an array of String property names to copy onto a new object
     * @param {Object} obj The object to copy from
     * @return {Object} A new object with only properties from `names` on it.
     * @see R.pick
     * @example
     *
     *      R.pickAll(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, d: 4}
     *      R.pickAll(['a', 'e', 'f'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, e: undefined, f: undefined}
     */
    var pickAll = _curry2(function pickAll(names, obj) {
        var result = {};
        var idx = 0;
        var len = names.length;
        while (idx < len) {
            var name = names[idx];
            result[name] = obj[name];
            idx += 1;
        }
        return result;
    });

    /**
     * Returns a partial copy of an object containing only the keys that
     * satisfy the supplied predicate.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig (v, k -> Boolean) -> {k: v} -> {k: v}
     * @param {Function} pred A predicate to determine whether or not a key
     *        should be included on the output object.
     * @param {Object} obj The object to copy from
     * @return {Object} A new object with only properties that satisfy `pred`
     *         on it.
     * @see R.pick
     * @example
     *
     *      var isUpperCase = function(val, key) { return key.toUpperCase() === key; }
     *      R.pickBy(isUpperCase, {a: 1, b: 2, A: 3, B: 4}); //=> {A: 3, B: 4}
     */
    var pickBy = _curry2(function pickBy(test, obj) {
        var result = {};
        for (var prop in obj) {
            if (test(obj[prop], prop, obj)) {
                result[prop] = obj[prop];
            }
        }
        return result;
    });

    /**
     * Returns a new list with the given element at the front, followed by the contents of the
     * list.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> [a] -> [a]
     * @param {*} el The item to add to the head of the output list.
     * @param {Array} list The array to add to the tail of the output list.
     * @return {Array} A new array.
     * @example
     *
     *      R.prepend('fee', ['fi', 'fo', 'fum']); //=> ['fee', 'fi', 'fo', 'fum']
     */
    var prepend = _curry2(_prepend);

    /**
     * Returns a function that when supplied an object returns the indicated property of that object, if it exists.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig s -> {s: a} -> a
     * @param {String} p The property name
     * @param {Object} obj The object to query
     * @return {*} The value at `obj.p`.
     * @example
     *
     *      R.prop('x', {x: 100}); //=> 100
     *      R.prop('x', {}); //=> undefined
     */
    var prop = _curry2(function prop(p, obj) {
        return obj[p];
    });

    /**
     * If the given, non-null object has an own property with the specified name,
     * returns the value of that property.
     * Otherwise returns the provided default value.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig a -> String -> Object -> a
     * @param {*} val The default value.
     * @param {String} p The name of the property to return.
     * @param {Object} obj The object to query.
     * @return {*} The value of given property of the supplied object or the default value.
     * @example
     *
     *      var alice = {
     *        name: 'ALICE',
     *        age: 101
     *      };
     *      var favorite = R.prop('favoriteLibrary');
     *      var favoriteWithDefault = R.propOr('Ramda', 'favoriteLibrary');
     *
     *      favorite(alice);  //=> undefined
     *      favoriteWithDefault(alice);  //=> 'Ramda'
     */
    var propOr = _curry3(function propOr(val, p, obj) {
        return obj != null && _has(p, obj) ? obj[p] : val;
    });

    /**
     * Acts as multiple `get`: array of keys in, array of values out. Preserves order.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig [k] -> {k: v} -> [v]
     * @param {Array} ps The property names to fetch
     * @param {Object} obj The object to query
     * @return {Array} The corresponding values or partially applied function.
     * @example
     *
     *      R.props(['x', 'y'], {x: 1, y: 2}); //=> [1, 2]
     *      R.props(['c', 'a', 'b'], {b: 2, a: 1}); //=> [undefined, 1, 2]
     *
     *      var fullName = R.compose(R.join(' '), R.props(['first', 'last']));
     *      fullName({last: 'Bullet-Tooth', age: 33, first: 'Tony'}); //=> 'Tony Bullet-Tooth'
     */
    var props = _curry2(function props(ps, obj) {
        var len = ps.length;
        var out = [];
        var idx = 0;
        while (idx < len) {
            out[idx] = obj[ps[idx]];
            idx += 1;
        }
        return out;
    });

    /**
     * Returns a list of numbers from `from` (inclusive) to `to`
     * (exclusive).
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> Number -> [Number]
     * @param {Number} from The first number in the list.
     * @param {Number} to One more than the last number in the list.
     * @return {Array} The list of numbers in tthe set `[a, b)`.
     * @example
     *
     *      R.range(1, 5);    //=> [1, 2, 3, 4]
     *      R.range(50, 53);  //=> [50, 51, 52]
     */
    var range = _curry2(function range(from, to) {
        var result = [];
        var n = from;
        while (n < to) {
            result[result.length] = n;
            n += 1;
        }
        return result;
    });

    /**
     * Like `reduce`, but passes additional parameters to the predicate function.
     *
     * The iterator function receives four values: *(acc, value, index, list)*
     *
     * Note: `R.reduceIndexed` does not skip deleted or unassigned indices (sparse arrays),
     * unlike the native `Array.prototype.reduce` method. For more details on this behavior,
     * see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce#Description
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a,b,i,[b] -> a) -> a -> [b] -> a
     * @param {Function} fn The iterator function. Receives four values: the accumulator, the
     *        current element from `list`, that element's index, and the entire `list` itself.
     * @param {*} acc The accumulator value.
     * @param {Array} list The list to iterate over.
     * @return {*} The final, accumulated value.
     * @deprecated since v0.15.0
     * @see R.addIndex
     * @example
     *
     *      var letters = ['a', 'b', 'c'];
     *      var objectify = function(accObject, elem, idx, list) {
     *        accObject[elem] = idx;
     *        return accObject;
     *      };
     *
     *      R.reduceIndexed(objectify, {}, letters); //=> { 'a': 0, 'b': 1, 'c': 2 }
     */
    var reduceIndexed = _curry3(function reduceIndexed(fn, acc, list) {
        var idx = 0, len = list.length;
        while (idx < len) {
            acc = fn(acc, list[idx], idx, list);
            idx += 1;
        }
        return acc;
    });

    /**
     * Returns a single item by iterating through the list, successively calling the iterator
     * function and passing it an accumulator value and the current value from the array, and
     * then passing the result to the next call.
     *
     * Similar to `reduce`, except moves through the input list from the right to the left.
     *
     * The iterator function receives two values: *(acc, value)*
     *
     * Note: `R.reduceRight` does not skip deleted or unassigned indices (sparse arrays), unlike
     * the native `Array.prototype.reduce` method. For more details on this behavior, see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduceRight#Description
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a,b -> a) -> a -> [b] -> a
     * @param {Function} fn The iterator function. Receives two values, the accumulator and the
     *        current element from the array.
     * @param {*} acc The accumulator value.
     * @param {Array} list The list to iterate over.
     * @return {*} The final, accumulated value.
     * @example
     *
     *      var pairs = [ ['a', 1], ['b', 2], ['c', 3] ];
     *      var flattenPairs = function(acc, pair) {
     *        return acc.concat(pair);
     *      };
     *
     *      R.reduceRight(flattenPairs, [], pairs); //=> [ 'c', 3, 'b', 2, 'a', 1 ]
     */
    var reduceRight = _curry3(function reduceRight(fn, acc, list) {
        var idx = list.length - 1;
        while (idx >= 0) {
            acc = fn(acc, list[idx]);
            idx -= 1;
        }
        return acc;
    });

    /**
     * Like `reduceRight`, but passes additional parameters to the predicate function. Moves through
     * the input list from the right to the left.
     *
     * The iterator function receives four values: *(acc, value, index, list)*.
     *
     * Note: `R.reduceRightIndexed` does not skip deleted or unassigned indices (sparse arrays),
     * unlike the native `Array.prototype.reduce` method. For more details on this behavior,
     * see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduceRight#Description
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a,b,i,[b] -> a -> [b] -> a
     * @param {Function} fn The iterator function. Receives four values: the accumulator, the
     *        current element from `list`, that element's index, and the entire `list` itself.
     * @param {*} acc The accumulator value.
     * @param {Array} list The list to iterate over.
     * @return {*} The final, accumulated value.
     * @deprecated since v0.15.0
     * @see R.addIndex
     * @example
     *
     *      var letters = ['a', 'b', 'c'];
     *      var objectify = function(accObject, elem, idx, list) {
     *        accObject[elem] = idx;
     *        return accObject;
     *      };
     *
     *      R.reduceRightIndexed(objectify, {}, letters); //=> { 'c': 2, 'b': 1, 'a': 0 }
     */
    var reduceRightIndexed = _curry3(function reduceRightIndexed(fn, acc, list) {
        var idx = list.length - 1;
        while (idx >= 0) {
            acc = fn(acc, list[idx], idx, list);
            idx -= 1;
        }
        return acc;
    });

    /**
     * Returns a value wrapped to indicate that it is the final value of the
     * reduce and transduce functions.  The returned value
     * should be considered a black box: the internal structure is not
     * guaranteed to be stable.
     *
     * Note: this optimization is unavailable to functions not explicitly listed
     * above.  For instance, it is not currently supported by reduceIndexed,
     * reduceRight, or reduceRightIndexed.
     * @see R.reduce
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> *
     * @param {*} x The final value of the reduce.
     * @return {*} The wrapped value.
     * @example
     *
     *      R.reduce(
     *        R.pipe(R.add, R.ifElse(R.lte(10), R.reduced, R.identity)),
     *        0,
     *        [1, 2, 3, 4, 5]) // 10
     */
    var reduced = _curry1(_reduced);

    /**
     * Like `reject`, but passes additional parameters to the predicate function. The predicate
     * function is passed three arguments: *(value, index, list)*.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a, i, [a] -> Boolean) -> [a] -> [a]
     * @param {Function} fn The function called per iteration.
     * @param {Array} list The collection to iterate over.
     * @return {Array} The new filtered array.
     * @deprecated since v0.15.0
     * @see R.addIndex
     * @example
     *
     *      var lastTwo = function(val, idx, list) {
     *        return list.length - idx <= 2;
     *      };
     *
     *      R.rejectIndexed(lastTwo, [8, 6, 7, 5, 3, 0, 9]); //=> [8, 6, 7, 5, 3]
     */
    var rejectIndexed = _curry2(function rejectIndexed(fn, list) {
        return _filterIndexed(_complement(fn), list);
    });

    /**
     * Removes the sub-list of `list` starting at index `start` and containing
     * `count` elements.  _Note that this is not destructive_: it returns a
     * copy of the list with the changes.
     * <small>No lists have been harmed in the application of this function.</small>
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> Number -> [a] -> [a]
     * @param {Number} start The position to start removing elements
     * @param {Number} count The number of elements to remove
     * @param {Array} list The list to remove from
     * @return {Array} A new Array with `count` elements from `start` removed.
     * @example
     *
     *      R.remove(2, 3, [1,2,3,4,5,6,7,8]); //=> [1,2,6,7,8]
     */
    var remove = _curry3(function remove(start, count, list) {
        return _concat(_slice(list, 0, Math.min(start, list.length)), _slice(list, Math.min(list.length, start + count)));
    });

    /**
     * Replace a substring or regex match in a string with a replacement.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig RegExp|String -> String -> String -> String
     * @param {RegExp|String} pattern A regular expression or a substring to match.
     * @param {String} replacement The string to replace the matches with.
     * @param {String} str The String to do the search and replacement in.
     * @return {String} The result.
     * @example
     *
     *      R.replace('foo', 'bar', 'foo foo foo'); //=> 'bar foo foo'
     *      R.replace(/foo/, 'bar', 'foo foo foo'); //=> 'bar foo foo'
     *
     *      // Use the "g" (global) flag to replace all occurrences:
     *      R.replace(/foo/g, 'bar', 'foo foo foo'); //=> 'bar bar bar'
     */
    var replace = _curry3(function replace(regex, replacement, str) {
        return str.replace(regex, replacement);
    });

    /**
     * Returns a new list with the same elements as the original list, just
     * in the reverse order.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [a]
     * @param {Array} list The list to reverse.
     * @return {Array} A copy of the list in reverse order.
     * @example
     *
     *      R.reverse([1, 2, 3]);  //=> [3, 2, 1]
     *      R.reverse([1, 2]);     //=> [2, 1]
     *      R.reverse([1]);        //=> [1]
     *      R.reverse([]);         //=> []
     */
    var reverse = _curry1(function reverse(list) {
        return _slice(list).reverse();
    });

    /**
     * Scan is similar to reduce, but returns a list of successively reduced values from the left
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a,b -> a) -> a -> [b] -> [a]
     * @param {Function} fn The iterator function. Receives two values, the accumulator and the
     *        current element from the array
     * @param {*} acc The accumulator value.
     * @param {Array} list The list to iterate over.
     * @return {Array} A list of all intermediately reduced values.
     * @example
     *
     *      var numbers = [1, 2, 3, 4];
     *      var factorials = R.scan(R.multiply, 1, numbers); //=> [1, 1, 2, 6, 24]
     */
    var scan = _curry3(function scan(fn, acc, list) {
        var idx = 0, len = list.length, result = [acc];
        while (idx < len) {
            acc = fn(acc, list[idx]);
            result[idx + 1] = acc;
            idx += 1;
        }
        return result;
    });

    /**
     * Returns a copy of the list, sorted according to the comparator function, which should accept two values at a
     * time and return a negative number if the first value is smaller, a positive number if it's larger, and zero
     * if they are equal.  Please note that this is a **copy** of the list.  It does not modify the original.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a,a -> Number) -> [a] -> [a]
     * @param {Function} comparator A sorting function :: a -> b -> Int
     * @param {Array} list The list to sort
     * @return {Array} a new array with its elements sorted by the comparator function.
     * @example
     *
     *      var diff = function(a, b) { return a - b; };
     *      R.sort(diff, [4,2,7,5]); //=> [2, 4, 5, 7]
     */
    var sort = _curry2(function sort(comparator, list) {
        return _slice(list).sort(comparator);
    });

    /**
     * Sorts the list according to the supplied function.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig Ord b => (a -> b) -> [a] -> [a]
     * @param {Function} fn
     * @param {Array} list The list to sort.
     * @return {Array} A new list sorted by the keys generated by `fn`.
     * @example
     *
     *      var sortByFirstItem = R.sortBy(prop(0));
     *      var sortByNameCaseInsensitive = R.sortBy(compose(R.toLower, prop('name')));
     *      var pairs = [[-1, 1], [-2, 2], [-3, 3]];
     *      sortByFirstItem(pairs); //=> [[-3, 3], [-2, 2], [-1, 1]]
     *      var alice = {
     *        name: 'ALICE',
     *        age: 101
     *      };
     *      var bob = {
     *        name: 'Bob',
     *        age: -10
     *      };
     *      var clara = {
     *        name: 'clara',
     *        age: 314.159
     *      };
     *      var people = [clara, bob, alice];
     *      sortByNameCaseInsensitive(people); //=> [alice, bob, clara]
     */
    var sortBy = _curry2(function sortBy(fn, list) {
        return _slice(list).sort(function (a, b) {
            var aa = fn(a);
            var bb = fn(b);
            return aa < bb ? -1 : aa > bb ? 1 : 0;
        });
    });

    /**
     * Finds the first index of a substring in a string, returning -1 if it's not present
     *
     * @func
     * @memberOf R
     * @category String
     * @sig String -> String -> Number
     * @param {String} c A string to find.
     * @param {String} str The string to search in
     * @return {Number} The first index of `c` or -1 if not found.
     * @deprecated since v0.15.0
     * @example
     *
     *      R.strIndexOf('c', 'abcdefg'); //=> 2
     */
    var strIndexOf = _curry2(function strIndexOf(c, str) {
        return str.indexOf(c);
    });

    /**
     *
     * Finds the last index of a substring in a string, returning -1 if it's not present
     *
     * @func
     * @memberOf R
     * @category String
     * @sig String -> String -> Number
     * @param {String} c A string to find.
     * @param {String} str The string to search in
     * @return {Number} The last index of `c` or -1 if not found.
     * @deprecated since v0.15.0
     * @example
     *
     *      R.strLastIndexOf('a', 'banana split'); //=> 5
     */
    var strLastIndexOf = _curry2(function (c, str) {
        return str.lastIndexOf(c);
    });

    /**
     * Subtracts two numbers. Equivalent to `a - b` but curried.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig Number -> Number -> Number
     * @param {Number} a The first value.
     * @param {Number} b The second value.
     * @return {Number} The result of `a - b`.
     * @example
     *
     *      R.subtract(10, 8); //=> 2
     *
     *      var minus5 = R.subtract(R.__, 5);
     *      minus5(17); //=> 12
     *
     *      var complementaryAngle = R.subtract(90);
     *      complementaryAngle(30); //=> 60
     *      complementaryAngle(72); //=> 18
     */
    var subtract = _curry2(function subtract(a, b) {
        return a - b;
    });

    /**
     * Runs the given function with the supplied object, then returns the object.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (a -> *) -> a -> a
     * @param {Function} fn The function to call with `x`. The return value of `fn` will be thrown away.
     * @param {*} x
     * @return {*} `x`.
     * @example
     *
     *      var sayX = function(x) { console.log('x is ' + x); };
     *      R.tap(sayX, 100); //=> 100
     *      //-> 'x is 100'
     */
    var tap = _curry2(function tap(fn, x) {
        fn(x);
        return x;
    });

    /**
     * Determines whether a given string matches a given regular expression.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig RegExp -> String -> Boolean
     * @param {RegExp} pattern
     * @param {String} str
     * @return {Boolean}
     * @example
     *
     *      R.test(/^x/, 'xyz'); //=> true
     *      R.test(/^y/, 'xyz'); //=> false
     */
    var test = _curry2(function test(pattern, str) {
        return _cloneRegExp(pattern).test(str);
    });

    /**
     * Calls an input function `n` times, returning an array containing the results of those
     * function calls.
     *
     * `fn` is passed one argument: The current value of `n`, which begins at `0` and is
     * gradually incremented to `n - 1`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (i -> a) -> i -> [a]
     * @param {Function} fn The function to invoke. Passed one argument, the current value of `n`.
     * @param {Number} n A value between `0` and `n - 1`. Increments after each function call.
     * @return {Array} An array containing the return values of all calls to `fn`.
     * @example
     *
     *      R.times(R.identity, 5); //=> [0, 1, 2, 3, 4]
     */
    var times = _curry2(function times(fn, n) {
        var len = Number(n);
        var list = new Array(len);
        var idx = 0;
        while (idx < len) {
            list[idx] = fn(idx);
            idx += 1;
        }
        return list;
    });

    /**
     * Converts an object into an array of key, value arrays.
     * Only the object's own properties are used.
     * Note that the order of the output array is not guaranteed to be
     * consistent across different JS platforms.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {String: *} -> [[String,*]]
     * @param {Object} obj The object to extract from
     * @return {Array} An array of key, value arrays from the object's own properties.
     * @example
     *
     *      R.toPairs({a: 1, b: 2, c: 3}); //=> [['a', 1], ['b', 2], ['c', 3]]
     */
    var toPairs = _curry1(function toPairs(obj) {
        var pairs = [];
        for (var prop in obj) {
            if (_has(prop, obj)) {
                pairs[pairs.length] = [
                    prop,
                    obj[prop]
                ];
            }
        }
        return pairs;
    });

    /**
     * Converts an object into an array of key, value arrays.
     * The object's own properties and prototype properties are used.
     * Note that the order of the output array is not guaranteed to be
     * consistent across different JS platforms.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {String: *} -> [[String,*]]
     * @param {Object} obj The object to extract from
     * @return {Array} An array of key, value arrays from the object's own
     *         and prototype properties.
     * @example
     *
     *      var F = function() { this.x = 'X'; };
     *      F.prototype.y = 'Y';
     *      var f = new F();
     *      R.toPairsIn(f); //=> [['x','X'], ['y','Y']]
     */
    var toPairsIn = _curry1(function toPairsIn(obj) {
        var pairs = [];
        for (var prop in obj) {
            pairs[pairs.length] = [
                prop,
                obj[prop]
            ];
        }
        return pairs;
    });

    /**
     * Removes (strips) whitespace from both ends of the string.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig String -> String
     * @param {String} str The string to trim.
     * @return {String} Trimmed version of `str`.
     * @example
     *
     *      R.trim('   xyz  '); //=> 'xyz'
     *      R.map(R.trim, R.split(',', 'x, y, z')); //=> ['x', 'y', 'z']
     */
    var trim = function () {
        var ws = '\t\n\x0B\f\r \xA0\u1680\u180E\u2000\u2001\u2002\u2003' + '\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\u2028' + '\u2029\uFEFF';
        var zeroWidth = '\u200B';
        var hasProtoTrim = typeof String.prototype.trim === 'function';
        if (!hasProtoTrim || (ws.trim() || !zeroWidth.trim())) {
            return _curry1(function trim(str) {
                var beginRx = new RegExp('^[' + ws + '][' + ws + ']*');
                var endRx = new RegExp('[' + ws + '][' + ws + ']*$');
                return str.replace(beginRx, '').replace(endRx, '');
            });
        } else {
            return _curry1(function trim(str) {
                return str.trim();
            });
        }
    }();

    /**
     * Gives a single-word string description of the (native) type of a value, returning such
     * answers as 'Object', 'Number', 'Array', or 'Null'.  Does not attempt to distinguish user
     * Object types any further, reporting them all as 'Object'.
     *
     * @func
     * @memberOf R
     * @category Type
     * @sig (* -> {*}) -> String
     * @param {*} val The value to test
     * @return {String}
     * @example
     *
     *      R.type({}); //=> "Object"
     *      R.type(1); //=> "Number"
     *      R.type(false); //=> "Boolean"
     *      R.type('s'); //=> "String"
     *      R.type(null); //=> "Null"
     *      R.type([]); //=> "Array"
     *      R.type(/[A-z]/); //=> "RegExp"
     */
    var type = _curry1(function type(val) {
        return val === null ? 'Null' : val === undefined ? 'Undefined' : Object.prototype.toString.call(val).slice(8, -1);
    });

    /**
     * Takes a function `fn`, which takes a single array argument, and returns
     * a function which:
     *
     *   - takes any number of positional arguments;
     *   - passes these arguments to `fn` as an array; and
     *   - returns the result.
     *
     * In other words, R.unapply derives a variadic function from a function
     * which takes an array. R.unapply is the inverse of R.apply.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig ([*...] -> a) -> (*... -> a)
     * @param {Function} fn
     * @return {Function}
     * @see R.apply
     * @example
     *
     *      R.unapply(JSON.stringify)(1, 2, 3); //=> '[1,2,3]'
     */
    var unapply = _curry1(function unapply(fn) {
        return function () {
            return fn(_slice(arguments));
        };
    });

    /**
     * Wraps a function of any arity (including nullary) in a function that accepts exactly 1
     * parameter. Any extraneous parameters will not be passed to the supplied function.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (* -> b) -> (a -> b)
     * @param {Function} fn The function to wrap.
     * @return {Function} A new function wrapping `fn`. The new function is guaranteed to be of
     *         arity 1.
     * @example
     *
     *      var takesTwoArgs = function(a, b) {
     *        return [a, b];
     *      };
     *      takesTwoArgs.length; //=> 2
     *      takesTwoArgs(1, 2); //=> [1, 2]
     *
     *      var takesOneArg = R.unary(takesTwoArgs);
     *      takesOneArg.length; //=> 1
     *      // Only 1 argument is passed to the wrapped function
     *      takesOneArg(1, 2); //=> [1, undefined]
     */
    var unary = _curry1(function unary(fn) {
        return nAry(1, fn);
    });

    /**
     * Builds a list from a seed value. Accepts an iterator function, which returns either false
     * to stop iteration or an array of length 2 containing the value to add to the resulting
     * list and the seed to be used in the next call to the iterator function.
     *
     * The iterator function receives one argument: *(seed)*.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> [b]) -> * -> [b]
     * @param {Function} fn The iterator function. receives one argument, `seed`, and returns
     *        either false to quit iteration or an array of length two to proceed. The element
     *        at index 0 of this array will be added to the resulting array, and the element
     *        at index 1 will be passed to the next call to `fn`.
     * @param {*} seed The seed value.
     * @return {Array} The final list.
     * @example
     *
     *      var f = function(n) { return n > 50 ? false : [-n, n + 10] };
     *      R.unfold(f, 10); //=> [-10, -20, -30, -40, -50]
     */
    var unfold = _curry2(function unfold(fn, seed) {
        var pair = fn(seed);
        var result = [];
        while (pair && pair.length) {
            result[result.length] = pair[0];
            pair = fn(pair[1]);
        }
        return result;
    });

    /**
     * Returns a new list containing only one copy of each element in the original list, based
     * upon the value returned by applying the supplied predicate to two list elements. Prefers
     * the first item if two items compare equal based on the predicate.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a, a -> Boolean) -> [a] -> [a]
     * @param {Function} pred A predicate used to test whether two items are equal.
     * @param {Array} list The array to consider.
     * @return {Array} The list of unique items.
     * @example
     *
     *      var strEq = function(a, b) { return String(a) === String(b); };
     *      R.uniqWith(strEq)([1, '1', 2, 1]); //=> [1, 2]
     *      R.uniqWith(strEq)([{}, {}]);       //=> [{}]
     *      R.uniqWith(strEq)([1, '1', 1]);    //=> [1]
     *      R.uniqWith(strEq)(['1', 1, 1]);    //=> ['1']
     */
    var uniqWith = _curry2(function uniqWith(pred, list) {
        var idx = 0, len = list.length;
        var result = [], item;
        while (idx < len) {
            item = list[idx];
            if (!_containsWith(pred, item, result)) {
                result[result.length] = item;
            }
            idx += 1;
        }
        return result;
    });

    /**
     * Returns a new copy of the array with the element at the
     * provided index replaced with the given value.
     * @see R.adjust
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> a -> [a] -> [a]
     * @param {Number} idx The index to update.
     * @param {*} x The value to exist at the given index of the returned array.
     * @param {Array|Arguments} list The source array-like object to be updated.
     * @return {Array} A copy of `list` with the value at index `idx` replaced with `x`.
     * @example
     *
     *      R.update(1, 11, [0, 1, 2]);     //=> [0, 11, 2]
     *      R.update(1)(11)([0, 1, 2]);     //=> [0, 11, 2]
     */
    var update = _curry3(function (idx, x, list) {
        return adjust(always(x), idx, list);
    });

    /**
     * Returns a list of all the enumerable own properties of the supplied object.
     * Note that the order of the output array is not guaranteed across
     * different JS platforms.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {k: v} -> [v]
     * @param {Object} obj The object to extract values from
     * @return {Array} An array of the values of the object's own properties.
     * @example
     *
     *      R.values({a: 1, b: 2, c: 3}); //=> [1, 2, 3]
     */
    var values = _curry1(function values(obj) {
        var props = keys(obj);
        var len = props.length;
        var vals = [];
        var idx = 0;
        while (idx < len) {
            vals[idx] = obj[props[idx]];
            idx += 1;
        }
        return vals;
    });

    /**
     * Returns a list of all the properties, including prototype properties,
     * of the supplied object.
     * Note that the order of the output array is not guaranteed to be
     * consistent across different JS platforms.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {k: v} -> [v]
     * @param {Object} obj The object to extract values from
     * @return {Array} An array of the values of the object's own and prototype properties.
     * @example
     *
     *      var F = function() { this.x = 'X'; };
     *      F.prototype.y = 'Y';
     *      var f = new F();
     *      R.valuesIn(f); //=> ['X', 'Y']
     */
    var valuesIn = _curry1(function valuesIn(obj) {
        var prop, vs = [];
        for (prop in obj) {
            vs[vs.length] = obj[prop];
        }
        return vs;
    });

    /**
     * Takes a spec object and a test object; returns true if the test satisfies
     * the spec. Each of the spec's own properties must be a predicate function.
     * Each predicate is applied to the value of the corresponding property of
     * the test object. `where` returns true if all the predicates return true,
     * false otherwise.
     *
     * `where` is well suited to declaratively expressing constraints for other
     * functions such as `filter` and `find`.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {String: (* -> Boolean)} -> {String: *} -> Boolean
     * @param {Object} spec
     * @param {Object} testObj
     * @return {Boolean}
     * @example
     *
     *      // pred :: Object -> Boolean
     *      var pred = R.where({
     *        a: R.equals('foo'),
     *        b: R.complement(R.equals('bar')),
     *        x: R.gt(_, 10),
     *        y: R.lt(_, 20)
     *      });
     *
     *      pred({a: 'foo', b: 'xxx', x: 11, y: 19}); //=> true
     *      pred({a: 'xxx', b: 'xxx', x: 11, y: 19}); //=> false
     *      pred({a: 'foo', b: 'bar', x: 11, y: 19}); //=> false
     *      pred({a: 'foo', b: 'xxx', x: 10, y: 19}); //=> false
     *      pred({a: 'foo', b: 'xxx', x: 11, y: 20}); //=> false
     */
    var where = _curry2(function where(spec, testObj) {
        for (var prop in spec) {
            if (_has(prop, spec) && !spec[prop](testObj[prop])) {
                return false;
            }
        }
        return true;
    });

    /**
     * Creates a new list out of the two supplied by creating each possible
     * pair from the lists.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [b] -> [[a,b]]
     * @param {Array} as The first list.
     * @param {Array} bs The second list.
     * @return {Array} The list made by combining each possible pair from
     *         `as` and `bs` into pairs (`[a, b]`).
     * @example
     *
     *      R.xprod([1, 2], ['a', 'b']); //=> [[1, 'a'], [1, 'b'], [2, 'a'], [2, 'b']]
     */
    // = xprodWith(prepend); (takes about 3 times as long...)
    var xprod = _curry2(function xprod(a, b) {
        // = xprodWith(prepend); (takes about 3 times as long...)
        var idx = 0;
        var ilen = a.length;
        var j;
        var jlen = b.length;
        var result = [];
        while (idx < ilen) {
            j = 0;
            while (j < jlen) {
                result[result.length] = [
                    a[idx],
                    b[j]
                ];
                j += 1;
            }
            idx += 1;
        }
        return result;
    });

    /**
     * Creates a new list out of the two supplied by pairing up
     * equally-positioned items from both lists.  The returned list is
     * truncated to the length of the shorter of the two input lists.
     * Note: `zip` is equivalent to `zipWith(function(a, b) { return [a, b] })`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [b] -> [[a,b]]
     * @param {Array} list1 The first array to consider.
     * @param {Array} list2 The second array to consider.
     * @return {Array} The list made by pairing up same-indexed elements of `list1` and `list2`.
     * @example
     *
     *      R.zip([1, 2, 3], ['a', 'b', 'c']); //=> [[1, 'a'], [2, 'b'], [3, 'c']]
     */
    var zip = _curry2(function zip(a, b) {
        var rv = [];
        var idx = 0;
        var len = Math.min(a.length, b.length);
        while (idx < len) {
            rv[idx] = [
                a[idx],
                b[idx]
            ];
            idx += 1;
        }
        return rv;
    });

    /**
     * Creates a new object out of a list of keys and a list of values.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [String] -> [*] -> {String: *}
     * @param {Array} keys The array that will be properties on the output object.
     * @param {Array} values The list of values on the output object.
     * @return {Object} The object made by pairing up same-indexed elements of `keys` and `values`.
     * @example
     *
     *      R.zipObj(['a', 'b', 'c'], [1, 2, 3]); //=> {a: 1, b: 2, c: 3}
     */
    var zipObj = _curry2(function zipObj(keys, values) {
        var idx = 0, len = keys.length, out = {};
        while (idx < len) {
            out[keys[idx]] = values[idx];
            idx += 1;
        }
        return out;
    });

    /**
     * Creates a new list out of the two supplied by applying the function to
     * each equally-positioned pair in the lists. The returned list is
     * truncated to the length of the shorter of the two input lists.
     *
     * @function
     * @memberOf R
     * @category List
     * @sig (a,b -> c) -> [a] -> [b] -> [c]
     * @param {Function} fn The function used to combine the two elements into one value.
     * @param {Array} list1 The first array to consider.
     * @param {Array} list2 The second array to consider.
     * @return {Array} The list made by combining same-indexed elements of `list1` and `list2`
     *         using `fn`.
     * @example
     *
     *      var f = function(x, y) {
     *        // ...
     *      };
     *      R.zipWith(f, [1, 2, 3], ['a', 'b', 'c']);
     *      //=> [f(1, 'a'), f(2, 'b'), f(3, 'c')]
     */
    var zipWith = _curry3(function zipWith(fn, a, b) {
        var rv = [], idx = 0, len = Math.min(a.length, b.length);
        while (idx < len) {
            rv[idx] = fn(a[idx], b[idx]);
            idx += 1;
        }
        return rv;
    });

    /**
     * A function that always returns `false`. Any passed in parameters are ignored.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig * -> false
     * @see R.always
     * @return {Boolean} false
     * @example
     *
     *      R.F(); //=> false
     */
    var F = always(false);

    /**
     * A function that always returns `true`. Any passed in parameters are ignored.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig * -> true
     * @see R.always
     * @return {Boolean} `true`.
     * @example
     *
     *      R.T(); //=> true
     */
    var T = always(true);

    var _append = function _append(el, list) {
        return _concat(list, [el]);
    };

    var _assocPath = function _assocPath(path, val, obj) {
        switch (path.length) {
        case 0:
            return obj;
        case 1:
            return _assoc(path[0], val, obj);
        default:
            return _assoc(path[0], _assocPath(_slice(path, 1), val, Object(obj[path[0]])), obj);
        }
    };

    /**
     * Copies an object.
     *
     * @private
     * @param {*} value The value to be copied
     * @param {Array} refFrom Array containing the source references
     * @param {Array} refTo Array containing the copied source references
     * @return {*} The copied value.
     */
    var _baseCopy = function _baseCopy(value, refFrom, refTo) {
        var copy = function copy(copiedValue) {
            var len = refFrom.length;
            var idx = 0;
            while (idx < len) {
                if (value === refFrom[idx]) {
                    return refTo[idx];
                }
                idx += 1;
            }
            refFrom[idx + 1] = value;
            refTo[idx + 1] = copiedValue;
            for (var key in value) {
                copiedValue[key] = _baseCopy(value[key], refFrom, refTo);
            }
            return copiedValue;
        };
        switch (type(value)) {
        case 'Object':
            return copy({});
        case 'Array':
            return copy([]);
        case 'Date':
            return new Date(value);
        case 'RegExp':
            return _cloneRegExp(value);
        default:
            return value;
        }
    };

    /**
     * Similar to hasMethod, this checks whether a function has a [methodname]
     * function. If it isn't an array it will execute that function otherwise it will
     * default to the ramda implementation.
     *
     * @private
     * @param {Function} fn ramda implemtation
     * @param {String} methodname property to check for a custom implementation
     * @return {Object} Whatever the return value of the method is.
     */
    var _checkForMethod = function _checkForMethod(methodname, fn) {
        return function () {
            var length = arguments.length;
            if (length === 0) {
                return fn();
            }
            var obj = arguments[length - 1];
            return _isArray(obj) || typeof obj[methodname] !== 'function' ? fn.apply(this, arguments) : obj[methodname].apply(obj, _slice(arguments, 0, length - 1));
        };
    };

    var _composeL = function _composeL(innerLens, outerLens) {
        return lens(_compose(innerLens, outerLens), function (x, source) {
            var newInnerValue = innerLens.set(x, outerLens(source));
            return outerLens.set(newInnerValue, source);
        });
    };

    /**
     * A right-associative two-argument composition function like `_compose`
     * but with automatic handling of promises (or, more precisely,
     * "thenables"). This function is used to construct a more general
     * `composeP` function, which accepts any number of arguments.
     *
     * @private
     * @category Function
     * @param {Function} f A function.
     * @param {Function} g A function.
     * @return {Function} A new function that is the equivalent of `f(g(x))`.
     * @example
     *
     *      var Q = require('q');
     *      var double = function(x) { return x * 2; };
     *      var squareAsync = function(x) { return Q.when(x * x); };
     *      var squareAsyncThenDouble = _composeP(double, squareAsync);
     *
     *      squareAsyncThenDouble(5)
     *        .then(function(result) {
     *          // the result is now 50.
     *        });
     */
    var _composeP = function _composeP(f, g) {
        return function () {
            var context = this;
            var value = g.apply(this, arguments);
            if (_isThenable(value)) {
                return value.then(function (result) {
                    return f.call(context, result);
                });
            } else {
                return f.call(this, value);
            }
        };
    };

    /*
     * Returns a function that makes a multi-argument version of compose from
     * either _compose or _composeP.
     */
    var _createComposer = function _createComposer(composeFunction) {
        return function () {
            var fn = arguments[arguments.length - 1];
            var length = fn.length;
            var idx = arguments.length - 2;
            while (idx >= 0) {
                fn = composeFunction(arguments[idx], fn);
                idx -= 1;
            }
            return arity(length, fn);
        };
    };

    /**
     * Create a function which takes a list
     * and determines the winning value by a comparator. Used internally
     * by `R.max` and `R.min`
     *
     * @private
     * @param {Function} compatator a function to compare two items
     * @param {*} intialVal, default value if nothing else wins
     * @category Math
     * @return {Function}
     */
    var _createMaxMin = function _createMaxMin(comparator, initialVal) {
        return _curry1(function (list) {
            var idx = 0, winner = initialVal, computed;
            while (idx < list.length) {
                computed = +list[idx];
                if (comparator(computed, winner)) {
                    winner = computed;
                }
                idx += 1;
            }
            return winner;
        });
    };

    var _createPartialApplicator = function _createPartialApplicator(concat) {
        return function (fn) {
            var args = _slice(arguments, 1);
            return arity(Math.max(0, fn.length - args.length), function () {
                return fn.apply(this, concat(args, arguments));
            });
        };
    };

    /**
     * Internal curryN function.
     *
     * @private
     * @category Function
     * @param {Number} length The arity of the curried function.
     * @return {array} An array of arguments received thus far.
     * @param {Function} fn The function to curry.
     */
    var _curryN = function _curryN(length, received, fn) {
        return function () {
            var combined = [];
            var argsIdx = 0;
            var left = length;
            var combinedIdx = 0;
            while (combinedIdx < received.length || argsIdx < arguments.length) {
                var result;
                if (combinedIdx < received.length && (received[combinedIdx] == null || received[combinedIdx]['@@functional/placeholder'] !== true || argsIdx >= arguments.length)) {
                    result = received[combinedIdx];
                } else {
                    result = arguments[argsIdx];
                    argsIdx += 1;
                }
                combined[combinedIdx] = result;
                if (result == null || result['@@functional/placeholder'] !== true) {
                    left -= 1;
                }
                combinedIdx += 1;
            }
            return left <= 0 ? fn.apply(this, combined) : arity(left, _curryN(length, combined, fn));
        };
    };

    /**
     * Returns a function that dispatches with different strategies based on the
     * object in list position (last argument). If it is an array, executes [fn].
     * Otherwise, if it has a  function with [methodname], it will execute that
     * function (functor case). Otherwise, if it is a transformer, uses transducer
     * [xf] to return a new transformer (transducer case). Otherwise, it will
     * default to executing [fn].
     *
     * @private
     * @param {String} methodname property to check for a custom implementation
     * @param {Function} xf transducer to initialize if object is transformer
     * @param {Function} fn default ramda implementation
     * @return {Function} A function that dispatches on object in list position
     */
    var _dispatchable = function _dispatchable(methodname, xf, fn) {
        return function () {
            var length = arguments.length;
            if (length === 0) {
                return fn();
            }
            var obj = arguments[length - 1];
            if (!_isArray(obj)) {
                var args = _slice(arguments, 0, length - 1);
                if (typeof obj[methodname] === 'function') {
                    return obj[methodname].apply(obj, args);
                }
                if (_isTransformer(obj)) {
                    var transducer = xf.apply(null, args);
                    return transducer(obj);
                }
            }
            return fn.apply(this, arguments);
        };
    };

    var _dissocPath = function _dissocPath(path, obj) {
        switch (path.length) {
        case 0:
            return obj;
        case 1:
            return _dissoc(path[0], obj);
        default:
            var head = path[0];
            var tail = _slice(path, 1);
            return obj[head] == null ? obj : _assoc(head, _dissocPath(tail, obj[head]), obj);
        }
    };

    // The algorithm used to handle cyclic structures is
    // inspired by underscore's isEqual
    // RegExp equality algorithm: http://stackoverflow.com/a/10776635
    var _equals = function _eqDeep(a, b, stackA, stackB) {
        var typeA = type(a);
        if (typeA !== type(b)) {
            return false;
        }
        if (typeA === 'Boolean' || typeA === 'Number' || typeA === 'String') {
            return typeof a === 'object' ? typeof b === 'object' && identical(a.valueOf(), b.valueOf()) : identical(a, b);
        }
        if (identical(a, b)) {
            return true;
        }
        if (typeA === 'RegExp') {
            // RegExp equality algorithm: http://stackoverflow.com/a/10776635
            return a.source === b.source && a.global === b.global && a.ignoreCase === b.ignoreCase && a.multiline === b.multiline && a.sticky === b.sticky && a.unicode === b.unicode;
        }
        if (Object(a) === a) {
            if (typeA === 'Date' && a.getTime() !== b.getTime()) {
                return false;
            }
            var keysA = keys(a);
            if (keysA.length !== keys(b).length) {
                return false;
            }
            var idx = stackA.length - 1;
            while (idx >= 0) {
                if (stackA[idx] === a) {
                    return stackB[idx] === b;
                }
                idx -= 1;
            }
            stackA[stackA.length] = a;
            stackB[stackB.length] = b;
            idx = keysA.length - 1;
            while (idx >= 0) {
                var key = keysA[idx];
                if (!_has(key, b) || !_eqDeep(b[key], a[key], stackA, stackB)) {
                    return false;
                }
                idx -= 1;
            }
            stackA.pop();
            stackB.pop();
            return true;
        }
        return false;
    };

    /**
     * Assigns own enumerable properties of the other object to the destination
     * object preferring items in other.
     *
     * @private
     * @memberOf R
     * @category Object
     * @param {Object} destination The destination object.
     * @param {Object} other The other object to merge with destination.
     * @return {Object} The destination object.
     * @example
     *
     *      _extend({ 'name': 'fred', 'age': 10 }, { 'age': 40 });
     *      //=> { 'name': 'fred', 'age': 40 }
     */
    var _extend = function _extend(destination, other) {
        var props = keys(other);
        var idx = 0, length = props.length;
        while (idx < length) {
            destination[props[idx]] = other[props[idx]];
            idx += 1;
        }
        return destination;
    };

    /**
     * Private function that determines whether or not a provided object has a given method.
     * Does not ignore methods stored on the object's prototype chain. Used for dynamically
     * dispatching Ramda methods to non-Array objects.
     *
     * @private
     * @param {String} methodName The name of the method to check for.
     * @param {Object} obj The object to test.
     * @return {Boolean} `true` has a given method, `false` otherwise.
     * @example
     *
     *      var person = { name: 'John' };
     *      person.shout = function() { alert(this.name); };
     *
     *      _hasMethod('shout', person); //=> true
     *      _hasMethod('foo', person); //=> false
     */
    var _hasMethod = function _hasMethod(methodName, obj) {
        return obj != null && !_isArray(obj) && typeof obj[methodName] === 'function';
    };

    /**
     * `_makeFlat` is a helper function that returns a one-level or fully recursive function
     * based on the flag passed in.
     *
     * @private
     */
    var _makeFlat = function _makeFlat(recursive) {
        return function flatt(list) {
            var value, result = [], idx = 0, j, ilen = list.length, jlen;
            while (idx < ilen) {
                if (isArrayLike(list[idx])) {
                    value = recursive ? flatt(list[idx]) : list[idx];
                    j = 0;
                    jlen = value.length;
                    while (j < jlen) {
                        result[result.length] = value[j];
                        j += 1;
                    }
                } else {
                    result[result.length] = list[idx];
                }
                idx += 1;
            }
            return result;
        };
    };

    var _reduce = function () {
        function _arrayReduce(xf, acc, list) {
            var idx = 0, len = list.length;
            while (idx < len) {
                acc = xf['@@transducer/step'](acc, list[idx]);
                if (acc && acc['@@transducer/reduced']) {
                    acc = acc['@@transducer/value'];
                    break;
                }
                idx += 1;
            }
            return xf['@@transducer/result'](acc);
        }
        function _iterableReduce(xf, acc, iter) {
            var step = iter.next();
            while (!step.done) {
                acc = xf['@@transducer/step'](acc, step.value);
                if (acc && acc['@@transducer/reduced']) {
                    acc = acc['@@transducer/value'];
                    break;
                }
                step = iter.next();
            }
            return xf['@@transducer/result'](acc);
        }
        function _methodReduce(xf, acc, obj) {
            return xf['@@transducer/result'](obj.reduce(bind(xf['@@transducer/step'], xf), acc));
        }
        var symIterator = typeof Symbol !== 'undefined' ? Symbol.iterator : '@@iterator';
        return function _reduce(fn, acc, list) {
            if (typeof fn === 'function') {
                fn = _xwrap(fn);
            }
            if (isArrayLike(list)) {
                return _arrayReduce(fn, acc, list);
            }
            if (typeof list.reduce === 'function') {
                return _methodReduce(fn, acc, list);
            }
            if (list[symIterator] != null) {
                return _iterableReduce(fn, acc, list[symIterator]());
            }
            if (typeof list.next === 'function') {
                return _iterableReduce(fn, acc, list);
            }
            throw new TypeError('reduce: list must be array or iterable');
        };
    }();

    var _xall = function () {
        function XAll(f, xf) {
            this.xf = xf;
            this.f = f;
            this.all = true;
        }
        XAll.prototype['@@transducer/init'] = _xfBase.init;
        XAll.prototype['@@transducer/result'] = function (result) {
            if (this.all) {
                result = this.xf['@@transducer/step'](result, true);
            }
            return this.xf['@@transducer/result'](result);
        };
        XAll.prototype['@@transducer/step'] = function (result, input) {
            if (!this.f(input)) {
                this.all = false;
                result = _reduced(this.xf['@@transducer/step'](result, false));
            }
            return result;
        };
        return _curry2(function _xall(f, xf) {
            return new XAll(f, xf);
        });
    }();

    var _xany = function () {
        function XAny(f, xf) {
            this.xf = xf;
            this.f = f;
            this.any = false;
        }
        XAny.prototype['@@transducer/init'] = _xfBase.init;
        XAny.prototype['@@transducer/result'] = function (result) {
            if (!this.any) {
                result = this.xf['@@transducer/step'](result, false);
            }
            return this.xf['@@transducer/result'](result);
        };
        XAny.prototype['@@transducer/step'] = function (result, input) {
            if (this.f(input)) {
                this.any = true;
                result = _reduced(this.xf['@@transducer/step'](result, true));
            }
            return result;
        };
        return _curry2(function _xany(f, xf) {
            return new XAny(f, xf);
        });
    }();

    var _xdrop = function () {
        function XDrop(n, xf) {
            this.xf = xf;
            this.n = n;
        }
        XDrop.prototype['@@transducer/init'] = _xfBase.init;
        XDrop.prototype['@@transducer/result'] = _xfBase.result;
        XDrop.prototype.step = function (result, input) {
            if (this.n > 0) {
                this.n -= 1;
                return result;
            }
            return this.xf['@@transducer/step'](result, input);
        };
        return _curry2(function _xdrop(n, xf) {
            return new XDrop(n, xf);
        });
    }();

    var _xdropWhile = function () {
        function XDropWhile(f, xf) {
            this.xf = xf;
            this.f = f;
        }
        XDropWhile.prototype['@@transducer/init'] = _xfBase.init;
        XDropWhile.prototype['@@transducer/result'] = _xfBase.result;
        XDropWhile.prototype['@@transducer/step'] = function (result, input) {
            if (this.f) {
                if (this.f(input)) {
                    return result;
                }
                this.f = null;
            }
            return this.xf['@@transducer/step'](result, input);
        };
        return _curry2(function _xdropWhile(f, xf) {
            return new XDropWhile(f, xf);
        });
    }();

    var _xgroupBy = function () {
        function XGroupBy(f, xf) {
            this.xf = xf;
            this.f = f;
            this.inputs = {};
        }
        XGroupBy.prototype['@@transducer/init'] = _xfBase.init;
        XGroupBy.prototype['@@transducer/result'] = function (result) {
            var key;
            for (key in this.inputs) {
                if (_has(key, this.inputs)) {
                    result = this.xf['@@transducer/step'](result, this.inputs[key]);
                    if (result['@@transducer/reduced']) {
                        result = result['@@transducer/value'];
                        break;
                    }
                }
            }
            return this.xf['@@transducer/result'](result);
        };
        XGroupBy.prototype['@@transducer/step'] = function (result, input) {
            var key = this.f(input);
            this.inputs[key] = this.inputs[key] || [
                key,
                []
            ];
            this.inputs[key][1] = _append(input, this.inputs[key][1]);
            return result;
        };
        return _curry2(function _xgroupBy(f, xf) {
            return new XGroupBy(f, xf);
        });
    }();

    /**
     * Returns `true` if all elements of the list match the predicate, `false` if there are any
     * that don't.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> Boolean
     * @param {Function} fn The predicate function.
     * @param {Array} list The array to consider.
     * @return {Boolean} `true` if the predicate is satisfied by every element, `false`
     *         otherwise.
     * @example
     *
     *      var lessThan2 = R.flip(R.lt)(2);
     *      var lessThan3 = R.flip(R.lt)(3);
     *      R.all(lessThan2)([1, 2]); //=> false
     *      R.all(lessThan3)([1, 2]); //=> true
     */
    var all = _curry2(_dispatchable('all', _xall, _all));

    /**
     * A function that returns the first argument if it's falsy otherwise the second
     * argument. Note that this is NOT short-circuited, meaning that if expressions
     * are passed they are both evaluated.
     *
     * Dispatches to the `and` method of the first argument if applicable.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig * -> * -> *
     * @param {*} a any value
     * @param {*} b any other value
     * @return {*} the first argument if falsy otherwise the second argument.
     * @example
     *
     *      R.and(false, true); //=> false
     *      R.and(0, []); //=> 0
     *      R.and(null, ''); => null
     */
    var and = _curry2(function and(a, b) {
        return _hasMethod('and', a) ? a.and(b) : a && b;
    });

    /**
     * Returns `true` if at least one of elements of the list match the predicate, `false`
     * otherwise.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> Boolean
     * @param {Function} fn The predicate function.
     * @param {Array} list The array to consider.
     * @return {Boolean} `true` if the predicate is satisfied by at least one element, `false`
     *         otherwise.
     * @example
     *
     *      var lessThan0 = R.flip(R.lt)(0);
     *      var lessThan2 = R.flip(R.lt)(2);
     *      R.any(lessThan0)([1, 2]); //=> false
     *      R.any(lessThan2)([1, 2]); //=> true
     */
    var any = _curry2(_dispatchable('any', _xany, _any));

    /**
     * Returns a new list containing the contents of the given list, followed by the given
     * element.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> [a] -> [a]
     * @param {*} el The element to add to the end of the new list.
     * @param {Array} list The list whose contents will be added to the beginning of the output
     *        list.
     * @return {Array} A new list containing the contents of the old list followed by `el`.
     * @example
     *
     *      R.append('tests', ['write', 'more']); //=> ['write', 'more', 'tests']
     *      R.append('tests', []); //=> ['tests']
     *      R.append(['tests'], ['write', 'more']); //=> ['write', 'more', ['tests']]
     */
    var append = _curry2(_append);

    /**
     * Makes a shallow clone of an object, setting or overriding the nodes
     * required to create the given path, and placing the specific value at the
     * tail end of that path.  Note that this copies and flattens prototype
     * properties onto the new object as well.  All non-primitive properties
     * are copied by reference.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig [String] -> a -> {k: v} -> {k: v}
     * @param {Array} path the path to set
     * @param {*} val the new value
     * @param {Object} obj the object to clone
     * @return {Object} a new object similar to the original except along the specified path.
     * @example
     *
     *      R.assocPath(['a', 'b', 'c'], 42, {a: {b: {c: 0}}}); //=> {a: {b: {c: 42}}}
     */
    var assocPath = _curry3(_assocPath);

    /**
     * Wraps a function of any arity (including nullary) in a function that accepts exactly 2
     * parameters. Any extraneous parameters will not be passed to the supplied function.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (* -> c) -> (a, b -> c)
     * @param {Function} fn The function to wrap.
     * @return {Function} A new function wrapping `fn`. The new function is guaranteed to be of
     *         arity 2.
     * @example
     *
     *      var takesThreeArgs = function(a, b, c) {
     *        return [a, b, c];
     *      };
     *      takesThreeArgs.length; //=> 3
     *      takesThreeArgs(1, 2, 3); //=> [1, 2, 3]
     *
     *      var takesTwoArgs = R.binary(takesThreeArgs);
     *      takesTwoArgs.length; //=> 2
     *      // Only 2 arguments are passed to the wrapped function
     *      takesTwoArgs(1, 2, 3); //=> [1, 2, undefined]
     */
    var binary = _curry1(function binary(fn) {
        return nAry(2, fn);
    });

    /**
     * Creates a deep copy of the value which may contain (nested) `Array`s and
     * `Object`s, `Number`s, `String`s, `Boolean`s and `Date`s. `Function`s are
     * not copied, but assigned by their reference.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {*} -> {*}
     * @param {*} value The object or array to clone
     * @return {*} A new object or array.
     * @example
     *
     *      var objects = [{}, {}, {}];
     *      var objectsClone = R.clone(objects);
     *      objects[0] === objectsClone[0]; //=> false
     */
    var clone = _curry1(function clone(value) {
        return _baseCopy(value, [], []);
    });

    /**
     * Creates a new function that runs each of the functions supplied as parameters in turn,
     * passing the return value of each function invocation to the next function invocation,
     * beginning with whatever arguments were passed to the initial invocation.
     *
     * Note that `compose` is a right-associative function, which means the functions provided
     * will be invoked in order from right to left. In the example `var h = compose(f, g)`,
     * the function `h` is equivalent to `f( g(x) )`, where `x` represents the arguments
     * originally passed to `h`.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig ((y -> z), (x -> y), ..., (b -> c), (a... -> b)) -> (a... -> z)
     * @param {...Function} functions A variable number of functions.
     * @return {Function} A new function which represents the result of calling each of the
     *         input `functions`, passing the result of each function call to the next, from
     *         right to left.
     * @example
     *
     *      var triple = function(x) { return x * 3; };
     *      var double = function(x) { return x * 2; };
     *      var square = function(x) { return x * x; };
     *      var squareThenDoubleThenTriple = R.compose(triple, double, square);
     *
     *      //≅ triple(double(square(5)))
     *      squareThenDoubleThenTriple(5); //=> 150
     */
    var compose = _createComposer(_compose);

    /**
     * Creates a new lens that allows getting and setting values of nested properties, by
     * following each given lens in succession.
     *
     * Note that `composeL` is a right-associative function, which means the lenses provided
     * will be invoked in order from right to left.
     *
     * @func
     * @memberOf R
     * @category Function
     * @see R.lens
     * @sig ((y -> z), (x -> y), ..., (b -> c), (a -> b)) -> (a -> z)
     * @param {...Function} lenses A variable number of lenses.
     * @return {Function} A new lens which represents the result of calling each of the
     *         input `lenses`, passing the result of each getter/setter as the source
     *         to the next, from right to left.
     * @example
     *
     *      var headLens = R.lensIndex(0);
     *      var secondLens = R.lensIndex(1);
     *      var xLens = R.lensProp('x');
     *      var secondOfXOfHeadLens = R.composeL(secondLens, xLens, headLens);
     *
     *      var source = [{x: [0, 1], y: [2, 3]}, {x: [4, 5], y: [6, 7]}];
     *      secondOfXOfHeadLens(source); //=> 1
     *      secondOfXOfHeadLens.set(123, source); //=> [{x: [0, 123], y: [2, 3]}, {x: [4, 5], y: [6, 7]}]
     */
    var composeL = function () {
        var fn = arguments[arguments.length - 1];
        var idx = arguments.length - 2;
        while (idx >= 0) {
            fn = _composeL(arguments[idx], fn);
            idx -= 1;
        }
        return fn;
    };

    /**
     * Similar to `compose` but with automatic handling of promises (or, more
     * precisely, "thenables"). The behavior is identical  to that of
     * compose() if all composed functions return something other than
     * promises (i.e., objects with a .then() method). If one of the function
     * returns a promise, however, then the next function in the composition
     * is called asynchronously, in the success callback of the promise, using
     * the resolved value as an input. Note that `composeP` is a right-
     * associative function, just like `compose`.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig ((y -> z), (x -> y), ..., (b -> c), (a... -> b)) -> (a... -> z)
     * @param {...Function} functions A variable number of functions.
     * @return {Function} A new function which represents the result of calling each of the
     *         input `functions`, passing either the returned result or the asynchronously
     *         resolved value) of each function call to the next, from right to left.
     * @example
     *
     *      var Q = require('q');
     *      var triple = function(x) { return x * 3; };
     *      var double = function(x) { return x * 2; };
     *      var squareAsync = function(x) { return Q.when(x * x); };
     *      var squareAsyncThenDoubleThenTriple = R.composeP(triple, double, squareAsync);
     *
     *      //≅ squareAsync(5).then(function(x) { return triple(double(x)) };
     *      squareAsyncThenDoubleThenTriple(5)
     *        .then(function(result) {
     *          // result is 150
     *        });
     */
    var composeP = _createComposer(_composeP);

    /**
     * Returns a new list consisting of the elements of the first list followed by the elements
     * of the second.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [a] -> [a]
     * @param {Array} list1 The first list to merge.
     * @param {Array} list2 The second set to merge.
     * @return {Array} A new array consisting of the contents of `list1` followed by the
     *         contents of `list2`. If, instead of an Array for `list1`, you pass an
     *         object with a `concat` method on it, `concat` will call `list1.concat`
     *         and pass it the value of `list2`.
     *
     * @example
     *
     *      R.concat([], []); //=> []
     *      R.concat([4, 5, 6], [1, 2, 3]); //=> [4, 5, 6, 1, 2, 3]
     *      R.concat('ABC', 'DEF'); // 'ABCDEF'
     */
    var concat = _curry2(function (set1, set2) {
        if (_isArray(set2)) {
            return _concat(set1, set2);
        } else if (_hasMethod('concat', set1)) {
            return set1.concat(set2);
        } else {
            throw new TypeError('can\'t concat ' + typeof set1);
        }
    });

    /**
     * Returns a curried equivalent of the provided function, with the
     * specified arity. The curried function has two unusual capabilities.
     * First, its arguments needn't be provided one at a time. If `g` is
     * `R.curryN(3, f)`, the following are equivalent:
     *
     *   - `g(1)(2)(3)`
     *   - `g(1)(2, 3)`
     *   - `g(1, 2)(3)`
     *   - `g(1, 2, 3)`
     *
     * Secondly, the special placeholder value `R.__` may be used to specify
     * "gaps", allowing partial application of any combination of arguments,
     * regardless of their positions. If `g` is as above and `_` is `R.__`,
     * the following are equivalent:
     *
     *   - `g(1, 2, 3)`
     *   - `g(_, 2, 3)(1)`
     *   - `g(_, _, 3)(1)(2)`
     *   - `g(_, _, 3)(1, 2)`
     *   - `g(_, 2)(1)(3)`
     *   - `g(_, 2)(1, 3)`
     *   - `g(_, 2)(_, 3)(1)`
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig Number -> (* -> a) -> (* -> a)
     * @param {Number} length The arity for the returned function.
     * @param {Function} fn The function to curry.
     * @return {Function} A new, curried function.
     * @see R.curry
     * @example
     *
     *      var addFourNumbers = function() {
     *        return R.sum([].slice.call(arguments, 0, 4));
     *      };
     *
     *      var curriedAddFourNumbers = R.curryN(4, addFourNumbers);
     *      var f = curriedAddFourNumbers(1, 2);
     *      var g = f(3);
     *      g(4); //=> 10
     */
    var curryN = _curry2(function curryN(length, fn) {
        return arity(length, _curryN(length, [], fn));
    });

    /**
     * Makes a shallow clone of an object, omitting the property at the
     * given path. Note that this copies and flattens prototype properties
     * onto the new object as well.  All non-primitive properties are copied
     * by reference.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig [String] -> {k: v} -> {k: v}
     * @param {Array} path the path to set
     * @param {Object} obj the object to clone
     * @return {Object} a new object without the property at path
     * @example
     *
     *      R.dissocPath(['a', 'b', 'c'], {a: {b: {c: 42}}}); //=> {a: {b: {}}}
     */
    var dissocPath = _curry2(_dissocPath);

    /**
     * Returns a new list containing the last `n` elements of a given list, passing each value
     * to the supplied predicate function, skipping elements while the predicate function returns
     * `true`. The predicate function is passed one argument: *(value)*.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> [a]
     * @param {Function} fn The function called per iteration.
     * @param {Array} list The collection to iterate over.
     * @return {Array} A new array.
     * @example
     *
     *      var lteTwo = function(x) {
     *        return x <= 2;
     *      };
     *
     *      R.dropWhile(lteTwo, [1, 2, 3, 4, 3, 2, 1]); //=> [3, 4, 3, 2, 1]
     */
    var dropWhile = _curry2(_dispatchable('dropWhile', _xdropWhile, function dropWhile(pred, list) {
        var idx = 0, len = list.length;
        while (idx < len && pred(list[idx])) {
            idx += 1;
        }
        return _slice(list, idx);
    }));

    /**
     * `empty` returns an empty list for any argument, except when the argument satisfies the
     * Fantasy-land Monoid spec. In that case, this function will return the result of invoking
     * `empty` on that Monoid.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig * -> []
     * @return {Array} An empty array.
     * @example
     *
     *      R.empty([1,2,3,4,5]); //=> []
     */
    var empty = _curry1(function empty(x) {
        return _hasMethod('empty', x) ? x.empty() : [];
    });

    /**
     * Returns `true` if its arguments are equivalent, `false` otherwise.
     * Dispatches to an `equals` method if present. Handles cyclical data
     * structures.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig a -> b -> Boolean
     * @param {*} a
     * @param {*} b
     * @return {Boolean}
     * @example
     *
     *      R.equals(1, 1); //=> true
     *      R.equals(1, '1'); //=> false
     *      R.equals([1, 2, 3], [1, 2, 3]); //=> true
     *
     *      var a = {}; a.v = a;
     *      var b = {}; b.v = b;
     *      R.equals(a, b); //=> true
     */
    var equals = _curry2(function equals(a, b) {
        return _hasMethod('equals', a) ? a.equals(b) : _hasMethod('equals', b) ? b.equals(a) : _equals(a, b, [], []);
    });

    /**
     * Returns a new list containing only those items that match a given predicate function.
     * The predicate function is passed one argument: *(value)*.
     *
     * Note that `R.filter` does not skip deleted or unassigned indices, unlike the native
     * `Array.prototype.filter` method. For more details on this behavior, see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter#Description
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> [a]
     * @param {Function} fn The function called per iteration.
     * @param {Array} list The collection to iterate over.
     * @return {Array} The new filtered array.
     * @example
     *
     *      var isEven = function(n) {
     *        return n % 2 === 0;
     *      };
     *      R.filter(isEven, [1, 2, 3, 4]); //=> [2, 4]
     */
    var filter = _curry2(_dispatchable('filter', _xfilter, _filter));

    /**
     * Returns the first element of the list which matches the predicate, or `undefined` if no
     * element matches.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> a | undefined
     * @param {Function} fn The predicate function used to determine if the element is the
     *        desired one.
     * @param {Array} list The array to consider.
     * @return {Object} The element found, or `undefined`.
     * @example
     *
     *      var xs = [{a: 1}, {a: 2}, {a: 3}];
     *      R.find(R.propEq('a', 2))(xs); //=> {a: 2}
     *      R.find(R.propEq('a', 4))(xs); //=> undefined
     */
    var find = _curry2(_dispatchable('find', _xfind, function find(fn, list) {
        var idx = 0;
        var len = list.length;
        while (idx < len) {
            if (fn(list[idx])) {
                return list[idx];
            }
            idx += 1;
        }
    }));

    /**
     * Returns the index of the first element of the list which matches the predicate, or `-1`
     * if no element matches.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> Number
     * @param {Function} fn The predicate function used to determine if the element is the
     * desired one.
     * @param {Array} list The array to consider.
     * @return {Number} The index of the element found, or `-1`.
     * @example
     *
     *      var xs = [{a: 1}, {a: 2}, {a: 3}];
     *      R.findIndex(R.propEq('a', 2))(xs); //=> 1
     *      R.findIndex(R.propEq('a', 4))(xs); //=> -1
     */
    var findIndex = _curry2(_dispatchable('findIndex', _xfindIndex, function findIndex(fn, list) {
        var idx = 0;
        var len = list.length;
        while (idx < len) {
            if (fn(list[idx])) {
                return idx;
            }
            idx += 1;
        }
        return -1;
    }));

    /**
     * Returns the last element of the list which matches the predicate, or `undefined` if no
     * element matches.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> a | undefined
     * @param {Function} fn The predicate function used to determine if the element is the
     * desired one.
     * @param {Array} list The array to consider.
     * @return {Object} The element found, or `undefined`.
     * @example
     *
     *      var xs = [{a: 1, b: 0}, {a:1, b: 1}];
     *      R.findLast(R.propEq('a', 1))(xs); //=> {a: 1, b: 1}
     *      R.findLast(R.propEq('a', 4))(xs); //=> undefined
     */
    var findLast = _curry2(_dispatchable('findLast', _xfindLast, function findLast(fn, list) {
        var idx = list.length - 1;
        while (idx >= 0) {
            if (fn(list[idx])) {
                return list[idx];
            }
            idx -= 1;
        }
    }));

    /**
     * Returns the index of the last element of the list which matches the predicate, or
     * `-1` if no element matches.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> Number
     * @param {Function} fn The predicate function used to determine if the element is the
     * desired one.
     * @param {Array} list The array to consider.
     * @return {Number} The index of the element found, or `-1`.
     * @example
     *
     *      var xs = [{a: 1, b: 0}, {a:1, b: 1}];
     *      R.findLastIndex(R.propEq('a', 1))(xs); //=> 1
     *      R.findLastIndex(R.propEq('a', 4))(xs); //=> -1
     */
    var findLastIndex = _curry2(_dispatchable('findLastIndex', _xfindLastIndex, function findLastIndex(fn, list) {
        var idx = list.length - 1;
        while (idx >= 0) {
            if (fn(list[idx])) {
                return idx;
            }
            idx -= 1;
        }
        return -1;
    }));

    /**
     * Returns a new list by pulling every item out of it (and all its sub-arrays) and putting
     * them in a new array, depth-first.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [b]
     * @param {Array} list The array to consider.
     * @return {Array} The flattened list.
     * @example
     *
     *      R.flatten([1, 2, [3, 4], 5, [6, [7, 8, [9, [10, 11], 12]]]]);
     *      //=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
     */
    var flatten = _curry1(_makeFlat(true));

    /**
     * Iterate over an input `list`, calling a provided function `fn` for each element in the
     * list.
     *
     * `fn` receives one argument: *(value)*.
     *
     * Note: `R.forEach` does not skip deleted or unassigned indices (sparse arrays), unlike
     * the native `Array.prototype.forEach` method. For more details on this behavior, see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach#Description
     *
     * Also note that, unlike `Array.prototype.forEach`, Ramda's `forEach` returns the original
     * array. In some libraries this function is named `each`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> *) -> [a] -> [a]
     * @param {Function} fn The function to invoke. Receives one argument, `value`.
     * @param {Array} list The list to iterate over.
     * @return {Array} The original list.
     * @example
     *
     *      var printXPlusFive = function(x) { console.log(x + 5); };
     *      R.forEach(printXPlusFive, [1, 2, 3]); //=> [1, 2, 3]
     *      //-> 6
     *      //-> 7
     *      //-> 8
     */
    var forEach = _curry2(function forEach(fn, list) {
        return _hasMethod('forEach', list) ? list.forEach(fn) : _forEach(fn, list);
    });

    /**
     * Returns a list of function names of object's own functions
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {*} -> [String]
     * @param {Object} obj The objects with functions in it
     * @return {Array} A list of the object's own properties that map to functions.
     * @example
     *
     *      R.functions(R); // returns list of ramda's own function names
     *
     *      var F = function() { this.x = function(){}; this.y = 1; }
     *      F.prototype.z = function() {};
     *      F.prototype.a = 100;
     *      R.functions(new F()); //=> ["x"]
     */
    var functions = _curry1(_functionsWith(keys));

    /**
     * Returns a list of function names of object's own and prototype functions
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {*} -> [String]
     * @param {Object} obj The objects with functions in it
     * @return {Array} A list of the object's own properties and prototype
     *         properties that map to functions.
     * @example
     *
     *      R.functionsIn(R); // returns list of ramda's own and prototype function names
     *
     *      var F = function() { this.x = function(){}; this.y = 1; }
     *      F.prototype.z = function() {};
     *      F.prototype.a = 100;
     *      R.functionsIn(new F()); //=> ["x", "z"]
     */
    var functionsIn = _curry1(_functionsWith(keysIn));

    /**
     * Splits a list into sub-lists stored in an object, based on the result of calling a String-returning function
     * on each element, and grouping the results according to values returned.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> String) -> [a] -> {String: [a]}
     * @param {Function} fn Function :: a -> String
     * @param {Array} list The array to group
     * @return {Object} An object with the output of `fn` for keys, mapped to arrays of elements
     *         that produced that key when passed to `fn`.
     * @example
     *
     *      var byGrade = R.groupBy(function(student) {
     *        var score = student.score;
     *        return score < 65 ? 'F' :
     *               score < 70 ? 'D' :
     *               score < 80 ? 'C' :
     *               score < 90 ? 'B' : 'A';
     *      });
     *      var students = [{name: 'Abby', score: 84},
     *                      {name: 'Eddy', score: 58},
     *                      // ...
     *                      {name: 'Jack', score: 69}];
     *      byGrade(students);
     *      // {
     *      //   'A': [{name: 'Dianne', score: 99}],
     *      //   'B': [{name: 'Abby', score: 84}]
     *      //   // ...,
     *      //   'F': [{name: 'Eddy', score: 58}]
     *      // }
     */
    var groupBy = _curry2(_dispatchable('groupBy', _xgroupBy, function groupBy(fn, list) {
        return _reduce(function (acc, elt) {
            var key = fn(elt);
            acc[key] = _append(elt, acc[key] || (acc[key] = []));
            return acc;
        }, {}, list);
    }));

    /**
     * Returns the first element in a list.
     * In some libraries this function is named `first`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> a
     * @param {Array} list The array to consider.
     * @return {*} The first element of the list, or `undefined` if the list is empty.
     * @example
     *
     *      R.head(['fi', 'fo', 'fum']); //=> 'fi'
     */
    var head = nth(0);

    /**
     * Creates a function that will process either the `onTrue` or the `onFalse` function depending
     * upon the result of the `condition` predicate.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig (*... -> Boolean) -> (*... -> *) -> (*... -> *) -> (*... -> *)
     * @param {Function} condition A predicate function
     * @param {Function} onTrue A function to invoke when the `condition` evaluates to a truthy value.
     * @param {Function} onFalse A function to invoke when the `condition` evaluates to a falsy value.
     * @return {Function} A new unary function that will process either the `onTrue` or the `onFalse`
     *                    function depending upon the result of the `condition` predicate.
     * @example
     *
     *      // Flatten all arrays in the list but leave other values alone.
     *      var flattenArrays = R.map(R.ifElse(Array.isArray, R.flatten, R.identity));
     *
     *      flattenArrays([[0], [[10], [8]], 1234, {}]); //=> [[0], [10, 8], 1234, {}]
     *      flattenArrays([[[10], 123], [8, [10]], "hello"]); //=> [[10, 123], [8, 10], "hello"]
     */
    var ifElse = _curry3(function ifElse(condition, onTrue, onFalse) {
        return curryN(Math.max(condition.length, onTrue.length, onFalse.length), function _ifElse() {
            return condition.apply(this, arguments) ? onTrue.apply(this, arguments) : onFalse.apply(this, arguments);
        });
    });

    /**
     * Inserts the supplied element into the list, at index `index`.  _Note
     * that this is not destructive_: it returns a copy of the list with the changes.
     * <small>No lists have been harmed in the application of this function.</small>
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> a -> [a] -> [a]
     * @param {Number} index The position to insert the element
     * @param {*} elt The element to insert into the Array
     * @param {Array} list The list to insert into
     * @return {Array} A new Array with `elt` inserted at `index`.
     * @example
     *
     *      R.insert(2, 'x', [1,2,3,4]); //=> [1,2,'x',3,4]
     */
    var insert = _curry3(function insert(idx, elt, list) {
        idx = idx < list.length && idx >= 0 ? idx : list.length;
        return _concat(_append(elt, _slice(list, 0, idx)), _slice(list, idx));
    });

    /**
     * Combines two lists into a set (i.e. no duplicates) composed of those
     * elements common to both lists.  Duplication is determined according
     * to the value returned by applying the supplied predicate to two list
     * elements.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig (a,a -> Boolean) -> [a] -> [a] -> [a]
     * @param {Function} pred A predicate function that determines whether
     *        the two supplied elements are equal.
     * @param {Array} list1 One list of items to compare
     * @param {Array} list2 A second list of items to compare
     * @see R.intersection
     * @return {Array} A new list containing those elements common to both lists.
     * @example
     *
     *      var buffaloSpringfield = [
     *        {id: 824, name: 'Richie Furay'},
     *        {id: 956, name: 'Dewey Martin'},
     *        {id: 313, name: 'Bruce Palmer'},
     *        {id: 456, name: 'Stephen Stills'},
     *        {id: 177, name: 'Neil Young'}
     *      ];
     *      var csny = [
     *        {id: 204, name: 'David Crosby'},
     *        {id: 456, name: 'Stephen Stills'},
     *        {id: 539, name: 'Graham Nash'},
     *        {id: 177, name: 'Neil Young'}
     *      ];
     *
     *      var sameId = function(o1, o2) {return o1.id === o2.id;};
     *
     *      R.intersectionWith(sameId, buffaloSpringfield, csny);
     *      //=> [{id: 456, name: 'Stephen Stills'}, {id: 177, name: 'Neil Young'}]
     */
    var intersectionWith = _curry3(function intersectionWith(pred, list1, list2) {
        var results = [], idx = 0;
        while (idx < list1.length) {
            if (_containsWith(pred, list1[idx], list2)) {
                results[results.length] = list1[idx];
            }
            idx += 1;
        }
        return uniqWith(pred, results);
    });

    /**
     * Creates a new list with the separator interposed between elements.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> [a] -> [a]
     * @param {*} separator The element to add to the list.
     * @param {Array} list The list to be interposed.
     * @return {Array} The new list.
     * @example
     *
     *      R.intersperse('n', ['ba', 'a', 'a']); //=> ['ba', 'n', 'a', 'n', 'a']
     */
    var intersperse = _curry2(_checkForMethod('intersperse', function intersperse(separator, list) {
        var out = [];
        var idx = 0;
        var length = list.length;
        while (idx < length) {
            if (idx === length - 1) {
                out.push(list[idx]);
            } else {
                out.push(list[idx], separator);
            }
            idx += 1;
        }
        return out;
    }));

    /**
     * Same as R.invertObj, however this accounts for objects
     * with duplicate values by putting the values into an
     * array.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {s: x} -> {x: [ s, ... ]}
     * @param {Object} obj The object or array to invert
     * @return {Object} out A new object with keys
     * in an array.
     * @example
     *
     *      var raceResultsByFirstName = {
     *        first: 'alice',
     *        second: 'jake',
     *        third: 'alice',
     *      };
     *      R.invert(raceResultsByFirstName);
     *      //=> { 'alice': ['first', 'third'], 'jake':['second'] }
     */
    var invert = _curry1(function invert(obj) {
        var props = keys(obj);
        var len = props.length;
        var idx = 0;
        var out = {};
        while (idx < len) {
            var key = props[idx];
            var val = obj[key];
            var list = _has(val, out) ? out[val] : out[val] = [];
            list[list.length] = key;
            idx += 1;
        }
        return out;
    });

    /**
     * Returns a new object with the keys of the given object
     * as values, and the values of the given object as keys.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {s: x} -> {x: s}
     * @param {Object} obj The object or array to invert
     * @return {Object} out A new object
     * @example
     *
     *      var raceResults = {
     *        first: 'alice',
     *        second: 'jake'
     *      };
     *      R.invertObj(raceResults);
     *      //=> { 'alice': 'first', 'jake':'second' }
     *
     *      // Alternatively:
     *      var raceResults = ['alice', 'jake'];
     *      R.invertObj(raceResults);
     *      //=> { 'alice': '0', 'jake':'1' }
     */
    var invertObj = _curry1(function invertObj(obj) {
        var props = keys(obj);
        var len = props.length;
        var idx = 0;
        var out = {};
        while (idx < len) {
            var key = props[idx];
            out[obj[key]] = key;
            idx += 1;
        }
        return out;
    });

    /**
     * Turns a named method with a specified arity into a function
     * that can be called directly supplied with arguments and a target object.
     *
     * The returned function is curried and accepts `arity + 1` parameters where
     * the final parameter is the target object.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig Number -> String -> (a -> b -> ... -> n -> Object -> *)
     * @param {Number} arity Number of arguments the returned function should take
     *        before the target object.
     * @param {Function} method Name of the method to call.
     * @return {Function} A new curried function.
     * @example
     *
     *      var sliceFrom = R.invoker(1, 'slice');
     *      sliceFrom(6, 'abcdefghijklm'); //=> 'ghijklm'
     *      var sliceFrom6 = R.invoker(2, 'slice')(6);
     *      sliceFrom6(8, 'abcdefghijklm'); //=> 'gh'
     */
    var invoker = _curry2(function invoker(arity, method) {
        return curryN(arity + 1, function () {
            var target = arguments[arity];
            return target[method].apply(target, _slice(arguments, 0, arity));
        });
    });

    /**
     * Returns a string made by inserting the `separator` between each
     * element and concatenating all the elements into a single string.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig String -> [a] -> String
     * @param {Number|String} separator The string used to separate the elements.
     * @param {Array} xs The elements to join into a string.
     * @return {String} str The string made by concatenating `xs` with `separator`.
     * @example
     *
     *      var spacer = R.join(' ');
     *      spacer(['a', 2, 3.4]);   //=> 'a 2 3.4'
     *      R.join('|', [1, 2, 3]);    //=> '1|2|3'
     */
    var join = invoker(1, 'join');

    /**
     * Returns the last element from a list.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> a
     * @param {Array} list The array to consider.
     * @return {*} The last element of the list, or `undefined` if the list is empty.
     * @example
     *
     *      R.last(['fi', 'fo', 'fum']); //=> 'fum'
     */
    var last = nth(-1);

    /**
     * Creates a lens that will focus on index `n` of the source array.
     *
     * @func
     * @memberOf R
     * @category List
     * @see R.lens
     * @sig Number -> (a -> b)
     * @param {Number} n The index of the array that the returned lens will focus on.
     * @return {Function} the returned function has `set` and `map` properties that are
     *         also curried functions.
     * @example
     *
     *     var headLens = R.lensIndex(0);
     *     headLens([10, 20, 30, 40]); //=> 10
     *     headLens.set('mu', [10, 20, 30, 40]); //=> ['mu', 20, 30, 40]
     *     headLens.map(function(x) { return x + 1; }, [10, 20, 30, 40]); //=> [11, 20, 30, 40]
     */
    var lensIndex = _curry1(function lensIndex(n) {
        return lens(nth(n), update(n));
    });

    /**
     * Creates a lens that will focus on property `k` of the source object.
     *
     * @func
     * @memberOf R
     * @category Object
     * @see R.lens
     * @sig String -> (a -> b)
     * @param {String} k A string that represents a property to focus on.
     * @return {Function} the returned function has `set` and `map` properties that are
     *         also curried functions.
     * @example
     *
     *     var phraseLens = R.lensProp('phrase');
     *     var obj1 = { phrase: 'Absolute filth . . . and I LOVED it!'};
     *     var obj2 = { phrase: "What's all this, then?"};
     *     phraseLens(obj1); // => 'Absolute filth . . . and I LOVED it!'
     *     phraseLens(obj2); // => "What's all this, then?"
     *     phraseLens.set('Ooh Betty', obj1); //=> { phrase: 'Ooh Betty'}
     *     phraseLens.map(R.toUpper, obj2); //=> { phrase: "WHAT'S ALL THIS, THEN?"}
     */
    var lensProp = _curry1(function lensProp(k) {
        return lens(prop(k), assoc(k));
    });

    /**
     * Returns a new list, constructed by applying the supplied function to every element of the
     * supplied list.
     *
     * Note: `R.map` does not skip deleted or unassigned indices (sparse arrays), unlike the
     * native `Array.prototype.map` method. For more details on this behavior, see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map#Description
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> b) -> [a] -> [b]
     * @param {Function} fn The function to be called on every element of the input `list`.
     * @param {Array} list The list to be iterated over.
     * @return {Array} The new list.
     * @example
     *
     *      var double = function(x) {
     *        return x * 2;
     *      };
     *
     *      R.map(double, [1, 2, 3]); //=> [2, 4, 6]
     */
    var map = _curry2(_dispatchable('map', _xmap, _map));

    /**
     * Map, but for objects. Creates an object with the same keys as `obj` and values
     * generated by running each property of `obj` through `fn`. `fn` is passed one argument:
     * *(value)*.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig (v -> v) -> {k: v} -> {k: v}
     * @param {Function} fn A function called for each property in `obj`. Its return value will
     * become a new property on the return object.
     * @param {Object} obj The object to iterate over.
     * @return {Object} A new object with the same keys as `obj` and values that are the result
     *         of running each property through `fn`.
     * @example
     *
     *      var values = { x: 1, y: 2, z: 3 };
     *      var double = function(num) {
     *        return num * 2;
     *      };
     *
     *      R.mapObj(double, values); //=> { x: 2, y: 4, z: 6 }
     */
    var mapObj = _curry2(function mapObject(fn, obj) {
        return _reduce(function (acc, key) {
            acc[key] = fn(obj[key]);
            return acc;
        }, {}, keys(obj));
    });

    /**
     * Like `mapObj`, but but passes additional arguments to the predicate function. The
     * predicate function is passed three arguments: *(value, key, obj)*.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig (v, k, {k: v} -> v) -> {k: v} -> {k: v}
     * @param {Function} fn A function called for each property in `obj`. Its return value will
     *        become a new property on the return object.
     * @param {Object} obj The object to iterate over.
     * @return {Object} A new object with the same keys as `obj` and values that are the result
     *         of running each property through `fn`.
     * @example
     *
     *      var values = { x: 1, y: 2, z: 3 };
     *      var prependKeyAndDouble = function(num, key, obj) {
     *        return key + (num * 2);
     *      };
     *
     *      R.mapObjIndexed(prependKeyAndDouble, values); //=> { x: 'x2', y: 'y4', z: 'z6' }
     */
    var mapObjIndexed = _curry2(function mapObjectIndexed(fn, obj) {
        return _reduce(function (acc, key) {
            acc[key] = fn(obj[key], key, obj);
            return acc;
        }, {}, keys(obj));
    });

    /**
     * Tests a regular expression against a String
     *
     * @func
     * @memberOf R
     * @category String
     * @sig RegExp -> String -> [String] | null
     * @param {RegExp} rx A regular expression.
     * @param {String} str The string to match against
     * @return {Array} The list of matches, or null if no matches found.
     * @see R.invoker
     * @example
     *
     *      R.match(/([a-z]a)/g, 'bananas'); //=> ['ba', 'na', 'na']
     */
    var match = invoker(1, 'match');

    /**
     * Determines the largest of a list of numbers (or elements that can be cast to numbers)
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig [Number] -> Number
     * @see R.maxBy
     * @param {Array} list A list of numbers
     * @return {Number} The greatest number in the list.
     * @example
     *
     *      R.max([7, 3, 9, 2, 4, 9, 3]); //=> 9
     */
    var max = _createMaxMin(_gt, -Infinity);

    /**
     * Create a new object with the own properties of `a`
     * merged with the own properties of object `b`.
     * This function will *not* mutate passed-in objects.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {k: v} -> {k: v} -> {k: v}
     * @param {Object} a source object
     * @param {Object} b object with higher precedence in output
     * @return {Object} The destination object.
     * @example
     *
     *      R.merge({ 'name': 'fred', 'age': 10 }, { 'age': 40 });
     *      //=> { 'name': 'fred', 'age': 40 }
     *
     *      var resetToDefault = R.merge(R.__, {x: 0});
     *      resetToDefault({x: 5, y: 2}); //=> {x: 0, y: 2}
     */
    var merge = _curry2(function merge(a, b) {
        return _extend(_extend({}, a), b);
    });

    /**
     * Determines the smallest of a list of numbers (or elements that can be cast to numbers)
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig [Number] -> Number
     * @param {Array} list A list of numbers
     * @return {Number} The greatest number in the list.
     * @see R.minBy
     * @example
     *
     *      R.min([7, 3, 9, 2, 4, 9, 3]); //=> 2
     */
    var min = _createMaxMin(_lt, Infinity);

    /**
     * Returns `true` if no elements of the list match the predicate,
     * `false` otherwise.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> Boolean
     * @param {Function} fn The predicate function.
     * @param {Array} list The array to consider.
     * @return {Boolean} `true` if the predicate is not satisfied by every element, `false` otherwise.
     * @example
     *
     *      R.none(R.isNaN, [1, 2, 3]); //=> true
     *      R.none(R.isNaN, [1, 2, 3, NaN]); //=> false
     */
    var none = _curry2(_complement(_dispatchable('any', _xany, _any)));

    /**
     * A function that returns the first truthy of two arguments otherwise the
     * last argument. Note that this is NOT short-circuited, meaning that if
     * expressions are passed they are both evaluated.
     *
     * Dispatches to the `or` method of the first argument if applicable.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig * -> * -> *
     * @param {*} a any value
     * @param {*} b any other value
     * @return {*} the first truthy argument, otherwise the last argument.
     * @example
     *
     *      R.or(false, true); //=> true
     *      R.or(0, []); //=> []
     *      R.or(null, ''); => ''
     */
    var or = _curry2(function or(a, b) {
        return _hasMethod('or', a) ? a.or(b) : a || b;
    });

    /**
     * Takes a predicate and a list and returns the pair of lists of
     * elements which do and do not satisfy the predicate, respectively.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> [[a],[a]]
     * @param {Function} pred A predicate to determine which array the element belongs to.
     * @param {Array} list The array to partition.
     * @return {Array} A nested array, containing first an array of elements that satisfied the predicate,
     *         and second an array of elements that did not satisfy.
     * @example
     *
     *      R.partition(R.contains('s'), ['sss', 'ttt', 'foo', 'bars']);
     *      //=> [ [ 'sss', 'bars' ],  [ 'ttt', 'foo' ] ]
     */
    var partition = _curry2(function partition(pred, list) {
        return _reduce(function (acc, elt) {
            var xs = acc[pred(elt) ? 0 : 1];
            xs[xs.length] = elt;
            return acc;
        }, [
            [],
            []
        ], list);
    });

    /**
     * Determines whether a nested path on an object has a specific value,
     * in `R.equals` terms. Most likely used to filter a list.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig [String] -> * -> {String: *} -> Boolean
     * @param {Array} path The path of the nested property to use
     * @param {*} val The value to compare the nested property with
     * @param {Object} obj The object to check the nested property in
     * @return {Boolean} `true` if the value equals the nested object property,
     *         `false` otherwise.
     * @example
     *
     *      var user1 = { address: { zipCode: 90210 } };
     *      var user2 = { address: { zipCode: 55555 } };
     *      var user3 = { name: 'Bob' };
     *      var users = [ user1, user2, user3 ];
     *      var isFamous = R.pathEq(['address', 'zipCode'], 90210);
     *      R.filter(isFamous, users); //=> [ user1 ]
     */
    var pathEq = _curry3(function pathEq(path, val, obj) {
        return equals(_path(path, obj), val);
    });

    /**
     * Creates a new function that runs each of the functions supplied as parameters in turn,
     * passing the return value of each function invocation to the next function invocation,
     * beginning with whatever arguments were passed to the initial invocation.
     *
     * `pipe` is the mirror version of `compose`. `pipe` is left-associative, which means that
     * each of the functions provided is executed in order from left to right.
     *
     * In some libraries this function is named `sequence`.
     * @func
     * @memberOf R
     * @category Function
     * @sig ((a... -> b), (b -> c), ..., (x -> y), (y -> z)) -> (a... -> z)
     * @param {...Function} functions A variable number of functions.
     * @return {Function} A new function which represents the result of calling each of the
     *         input `functions`, passing the result of each function call to the next, from
     *         left to right.
     * @example
     *
     *      var triple = function(x) { return x * 3; };
     *      var double = function(x) { return x * 2; };
     *      var square = function(x) { return x * x; };
     *      var squareThenDoubleThenTriple = R.pipe(square, double, triple);
     *
     *      //≅ triple(double(square(5)))
     *      squareThenDoubleThenTriple(5); //=> 150
     */
    var pipe = function pipe() {
        return compose.apply(this, reverse(arguments));
    };

    /**
     * Creates a new lens that allows getting and setting values of nested properties, by
     * following each given lens in succession.
     *
     * `pipeL` is the mirror version of `composeL`. `pipeL` is left-associative, which means that
     * each of the functions provided is executed in order from left to right.
     *
     * @func
     * @memberOf R
     * @category Function
     * @see R.lens
     * @sig ((a -> b), (b -> c), ..., (x -> y), (y -> z)) -> (a -> z)
     * @param {...Function} lenses A variable number of lenses.
     * @return {Function} A new lens which represents the result of calling each of the
     *         input `lenses`, passing the result of each getter/setter as the source
     *         to the next, from right to left.
     * @example
     *
     *      var headLens = R.lensIndex(0);
     *      var secondLens = R.lensIndex(1);
     *      var xLens = R.lensProp('x');
     *      var headThenXThenSecondLens = R.pipeL(headLens, xLens, secondLens);
     *
     *      var source = [{x: [0, 1], y: [2, 3]}, {x: [4, 5], y: [6, 7]}];
     *      headThenXThenSecondLens(source); //=> 1
     *      headThenXThenSecondLens.set(123, source); //=> [{x: [0, 123], y: [2, 3]}, {x: [4, 5], y: [6, 7]}]
     */
    var pipeL = compose(apply(composeL), unapply(reverse));

    /**
     * Creates a new function that runs each of the functions supplied as parameters in turn,
     * passing to the next function invocation either the value returned by the previous
     * function or the resolved value if the returned value is a promise. In other words,
     * if some of the functions in the sequence return promises, `pipeP` pipes the values
     * asynchronously. If none of the functions return promises, the behavior is the same as
     * that of `pipe`.
     *
     * `pipeP` is the mirror version of `composeP`. `pipeP` is left-associative, which means that
     * each of the functions provided is executed in order from left to right.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig ((a... -> b), (b -> c), ..., (x -> y), (y -> z)) -> (a... -> z)
     * @param {...Function} functions A variable number of functions.
     * @return {Function} A new function which represents the result of calling each of the
     *         input `functions`, passing either the returned result or the asynchronously
     *         resolved value) of each function call to the next, from left to right.
     * @example
     *
     *      var Q = require('q');
     *      var triple = function(x) { return x * 3; };
     *      var double = function(x) { return x * 2; };
     *      var squareAsync = function(x) { return Q.when(x * x); };
     *      var squareAsyncThenDoubleThenTriple = R.pipeP(squareAsync, double, triple);
     *
     *      //≅ squareAsync(5).then(function(x) { return triple(double(x)) };
     *      squareAsyncThenDoubleThenTriple(5)
     *        .then(function(result) {
     *          // result is 150
     *        });
     */
    var pipeP = function pipeP() {
        return composeP.apply(this, reverse(arguments));
    };

    /**
     * Determines whether the given property of an object has a specific value,
     * in `R.equals` terms. Most likely used to filter a list.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig k -> v -> {k: v} -> Boolean
     * @param {Number|String} name The property name (or index) to use.
     * @param {*} val The value to compare the property with.
     * @return {Boolean} `true` if the properties are equal, `false` otherwise.
     * @example
     *
     *      var abby = {name: 'Abby', age: 7, hair: 'blond'};
     *      var fred = {name: 'Fred', age: 12, hair: 'brown'};
     *      var rusty = {name: 'Rusty', age: 10, hair: 'brown'};
     *      var alois = {name: 'Alois', age: 15, disposition: 'surly'};
     *      var kids = [abby, fred, rusty, alois];
     *      var hasBrownHair = R.propEq('hair', 'brown');
     *      R.filter(hasBrownHair, kids); //=> [fred, rusty]
     */
    var propEq = _curry3(function propEq(name, val, obj) {
        return equals(obj[name], val);
    });

    /**
     * Returns a single item by iterating through the list, successively calling the iterator
     * function and passing it an accumulator value and the current value from the array, and
     * then passing the result to the next call.
     *
     * The iterator function receives two values: *(acc, value)*.  It may use `R.reduced` to
     * shortcut the iteration.
     *
     * Note: `R.reduce` does not skip deleted or unassigned indices (sparse arrays), unlike
     * the native `Array.prototype.reduce` method. For more details on this behavior, see:
     * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce#Description
     * @see R.reduced
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a,b -> a) -> a -> [b] -> a
     * @param {Function} fn The iterator function. Receives two values, the accumulator and the
     *        current element from the array.
     * @param {*} acc The accumulator value.
     * @param {Array} list The list to iterate over.
     * @return {*} The final, accumulated value.
     * @example
     *
     *      var numbers = [1, 2, 3];
     *      var add = function(a, b) {
     *        return a + b;
     *      };
     *
     *      R.reduce(add, 10, numbers); //=> 16
     */
    var reduce = _curry3(_reduce);

    /**
     * Similar to `filter`, except that it keeps only values for which the given predicate
     * function returns falsy. The predicate function is passed one argument: *(value)*.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> [a]
     * @param {Function} fn The function called per iteration.
     * @param {Array} list The collection to iterate over.
     * @return {Array} The new filtered array.
     * @example
     *
     *      var isOdd = function(n) {
     *        return n % 2 === 1;
     *      };
     *      R.reject(isOdd, [1, 2, 3, 4]); //=> [2, 4]
     */
    var reject = _curry2(function reject(fn, list) {
        return filter(_complement(fn), list);
    });

    /**
     * Returns a fixed list of size `n` containing a specified identical value.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> n -> [a]
     * @param {*} value The value to repeat.
     * @param {Number} n The desired size of the output list.
     * @return {Array} A new array containing `n` `value`s.
     * @example
     *
     *      R.repeat('hi', 5); //=> ['hi', 'hi', 'hi', 'hi', 'hi']
     *
     *      var obj = {};
     *      var repeatedObjs = R.repeat(obj, 5); //=> [{}, {}, {}, {}, {}]
     *      repeatedObjs[0] === repeatedObjs[1]; //=> true
     */
    var repeat = _curry2(function repeat(value, n) {
        return times(always(value), n);
    });

    /**
     * Returns a list containing the elements of `xs` from `fromIndex` (inclusive)
     * to `toIndex` (exclusive).
     *
     * Dispatches to its third argument's `slice` method if present. As a
     * result, one may replace `[a]` with `String` in the type signature.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> Number -> [a] -> [a]
     * @param {Number} fromIndex The start index (inclusive).
     * @param {Number} toIndex The end index (exclusive).
     * @param {Array} xs The list to take elements from.
     * @return {Array} The slice of `xs` from `fromIndex` to `toIndex`.
     * @example
     *
     *      R.slice(1, 3, ['a', 'b', 'c', 'd']);        //=> ['b', 'c']
     *      R.slice(1, Infinity, ['a', 'b', 'c', 'd']); //=> ['b', 'c', 'd']
     *      R.slice(0, -1, ['a', 'b', 'c', 'd']);       //=> ['a', 'b', 'c']
     *      R.slice(-3, -1, ['a', 'b', 'c', 'd']);      //=> ['b', 'c']
     *      R.slice(0, 3, 'ramda');                     //=> 'ram'
     */
    var slice = _curry3(_checkForMethod('slice', function slice(fromIndex, toIndex, xs) {
        return Array.prototype.slice.call(xs, fromIndex, toIndex);
    }));

    /**
     * Splits a string into an array of strings based on the given
     * separator.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig String -> String -> [String]
     * @param {String} sep The separator string.
     * @param {String} str The string to separate into an array.
     * @return {Array} The array of strings from `str` separated by `str`.
     * @example
     *
     *      var pathComponents = R.split('/');
     *      R.tail(pathComponents('/usr/local/bin/node')); //=> ['usr', 'local', 'bin', 'node']
     *
     *      R.split('.', 'a.b.c.xyz.d'); //=> ['a', 'b', 'c', 'xyz', 'd']
     */
    var split = invoker(1, 'split');

    /**
     * Returns a string containing the characters of `str` from `fromIndex`
     * (inclusive) to `toIndex` (exclusive).
     *
     * @func
     * @memberOf R
     * @category String
     * @sig Number -> Number -> String -> String
     * @param {Number} fromIndex The start index (inclusive).
     * @param {Number} toIndex The end index (exclusive).
     * @param {String} str The string to slice.
     * @return {String}
     * @see R.slice
     * @deprecated since v0.15.0
     * @example
     *
     *      R.substring(2, 5, 'abcdefghijklm'); //=> 'cde'
     */
    var substring = slice;

    /**
     * Returns a string containing the characters of `str` from `fromIndex`
     * (inclusive) to the end of `str`.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig Number -> String -> String
     * @param {Number} fromIndex
     * @param {String} str
     * @return {String}
     * @deprecated since v0.15.0
     * @example
     *
     *      R.substringFrom(3, 'Ramda'); //=> 'da'
     *      R.substringFrom(-2, 'Ramda'); //=> 'da'
     */
    var substringFrom = substring(__, Infinity);

    /**
     * Returns a string containing the first `toIndex` characters of `str`.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig Number -> String -> String
     * @param {Number} toIndex
     * @param {String} str
     * @return {String}
     * @deprecated since v0.15.0
     * @example
     *
     *      R.substringTo(3, 'Ramda'); //=> 'Ram'
     *      R.substringTo(-2, 'Ramda'); //=> 'Ram'
     */
    var substringTo = substring(0);

    /**
     * Adds together all the elements of a list.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig [Number] -> Number
     * @param {Array} list An array of numbers
     * @return {Number} The sum of all the numbers in the list.
     * @see R.reduce
     * @example
     *
     *      R.sum([2,4,6,8,100,1]); //=> 121
     */
    var sum = reduce(_add, 0);

    /**
     * Returns all but the first element of a list. If the list provided has the `tail` method,
     * it will instead return `list.tail()`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [a]
     * @param {Array} list The array to consider.
     * @return {Array} A new array containing all but the first element of the input list, or an
     *         empty list if the input list is empty.
     * @example
     *
     *      R.tail(['fi', 'fo', 'fum']); //=> ['fo', 'fum']
     */
    var tail = _checkForMethod('tail', function (list) {
        return _slice(list, 1);
    });

    /**
     * Returns a new list containing the first `n` elements of the given list.
     * If `n > list.length`, returns a list of `list.length` elements.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * Dispatches to its second argument's `slice` method if present. As a
     * result, one may replace `[a]` with `String` in the type signature.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> [a] -> [a]
     * @param {Number} n The number of elements to return.
     * @param {Array} xs The collection to consider.
     * @return {Array}
     * @example
     *
     *      R.take(1, ['foo', 'bar', 'baz']); //=> ['foo']
     *      R.take(2, ['foo', 'bar', 'baz']); //=> ['foo', 'bar']
     *      R.take(3, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
     *      R.take(4, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
     *      R.take(3, 'ramda');               //=> 'ram'
     *
     *      var personnel = [
     *        'Dave Brubeck',
     *        'Paul Desmond',
     *        'Eugene Wright',
     *        'Joe Morello',
     *        'Gerry Mulligan',
     *        'Bob Bates',
     *        'Joe Dodge',
     *        'Ron Crotty'
     *      ];
     *
     *      takeFive(personnel);
     *      //=> ['Dave Brubeck', 'Paul Desmond', 'Eugene Wright', 'Joe Morello', 'Gerry Mulligan']
     */
    var take = _curry2(_dispatchable('take', _xtake, function take(n, xs) {
        return slice(0, n < 0 ? Infinity : n, xs);
    }));

    /**
     * Returns a new list containing the first `n` elements of a given list, passing each value
     * to the supplied predicate function, and terminating when the predicate function returns
     * `false`. Excludes the element that caused the predicate function to fail. The predicate
     * function is passed one argument: *(value)*.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> Boolean) -> [a] -> [a]
     * @param {Function} fn The function called per iteration.
     * @param {Array} list The collection to iterate over.
     * @return {Array} A new array.
     * @example
     *
     *      var isNotFour = function(x) {
     *        return !(x === 4);
     *      };
     *
     *      R.takeWhile(isNotFour, [1, 2, 3, 4]); //=> [1, 2, 3]
     */
    var takeWhile = _curry2(_dispatchable('takeWhile', _xtakeWhile, function takeWhile(fn, list) {
        var idx = 0, len = list.length;
        while (idx < len && fn(list[idx])) {
            idx += 1;
        }
        return _slice(list, 0, idx);
    }));

    /**
     * The lower case version of a string.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig String -> String
     * @param {String} str The string to lower case.
     * @return {String} The lower case version of `str`.
     * @example
     *
     *      R.toLower('XYZ'); //=> 'xyz'
     */
    var toLower = invoker(0, 'toLowerCase');

    /**
     * The upper case version of a string.
     *
     * @func
     * @memberOf R
     * @category String
     * @sig String -> String
     * @param {String} str The string to upper case.
     * @return {String} The upper case version of `str`.
     * @example
     *
     *      R.toUpper('abc'); //=> 'ABC'
     */
    var toUpper = invoker(0, 'toUpperCase');

    /**
     * Initializes a transducer using supplied iterator function. Returns a single item by
     * iterating through the list, successively calling the transformed iterator function and
     * passing it an accumulator value and the current value from the array, and then passing
     * the result to the next call.
     *
     * The iterator function receives two values: *(acc, value)*. It will be wrapped as a
     * transformer to initialize the transducer. A transformer can be passed directly in place
     * of an iterator function.  In both cases, iteration may be stopped early with the
     * `R.reduced` function.
     *
     * A transducer is a function that accepts a transformer and returns a transformer and can
     * be composed directly.
     *
     * A transformer is an an object that provides a 2-arity reducing iterator function, step,
     * 0-arity initial value function, init, and 1-arity result extraction function, result.
     * The step function is used as the iterator function in reduce. The result function is used
     * to convert the final accumulator into the return type and in most cases is R.identity.
     * The init function can be used to provide an initial accumulator, but is ignored by transduce.
     *
     * The iteration is performed with R.reduce after initializing the transducer.
     * @see R.reduce
     * @see R.reduced
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (c -> c) -> (a,b -> a) -> a -> [b] -> a
     * @param {Function} xf The transducer function. Receives a transformer and returns a transformer.
     * @param {Function} fn The iterator function. Receives two values, the accumulator and the
     *        current element from the array. Wrapped as transformer, if necessary, and used to
     *        initialize the transducer
     * @param {*} acc The initial accumulator value.
     * @param {Array} list The list to iterate over.
     * @see R.into
     * @return {*} The final, accumulated value.
     * @example
     *
     *      var numbers = [1, 2, 3, 4];
     *      var transducer = R.compose(R.map(R.add(1)), R.take(2));
     *
     *      R.transduce(transducer, R.flip(R.append), [], numbers); //=> [2, 3]
     */
    var transduce = curryN(4, function (xf, fn, acc, list) {
        return _reduce(xf(typeof fn === 'function' ? _xwrap(fn) : fn), acc, list);
    });

    /**
     * Returns a function of arity `n` from a (manually) curried function.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig Number -> (a -> b) -> (a -> c)
     * @param {Number} length The arity for the returned function.
     * @param {Function} fn The function to uncurry.
     * @return {Function} A new function.
     * @see R.curry
     * @example
     *
     *      var addFour = function(a) {
     *        return function(b) {
     *          return function(c) {
     *            return function(d) {
     *              return a + b + c + d;
     *            };
     *          };
     *        };
     *      };
     *
     *      var uncurriedAddFour = R.uncurryN(4, addFour);
     *      curriedAddFour(1, 2, 3, 4); //=> 10
     */
    var uncurryN = _curry2(function uncurryN(depth, fn) {
        return curryN(depth, function () {
            var currentDepth = 1;
            var value = fn;
            var idx = 0;
            var endIdx;
            while (currentDepth <= depth && typeof value === 'function') {
                endIdx = currentDepth === depth ? arguments.length : idx + value.length;
                value = value.apply(this, _slice(arguments, idx, endIdx));
                currentDepth += 1;
                idx = endIdx;
            }
            return value;
        });
    });

    /**
     * Combines two lists into a set (i.e. no duplicates) composed of the elements of each list.  Duplication is
     * determined according to the value returned by applying the supplied predicate to two list elements.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig (a,a -> Boolean) -> [a] -> [a] -> [a]
     * @param {Function} pred A predicate used to test whether two items are equal.
     * @param {Array} list1 The first list.
     * @param {Array} list2 The second list.
     * @return {Array} The first and second lists concatenated, with
     *         duplicates removed.
     * @see R.union
     * @example
     *
     *      function cmp(x, y) { return x.a === y.a; }
     *      var l1 = [{a: 1}, {a: 2}];
     *      var l2 = [{a: 1}, {a: 4}];
     *      R.unionWith(cmp, l1, l2); //=> [{a: 1}, {a: 2}, {a: 4}]
     */
    var unionWith = _curry3(function unionWith(pred, list1, list2) {
        return uniqWith(pred, _concat(list1, list2));
    });

    /**
     * Returns a new list containing only one copy of each element in the original list.
     * `R.equals` is used to determine equality.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [a]
     * @param {Array} list The array to consider.
     * @return {Array} The list of unique items.
     * @example
     *
     *      R.uniq([1, 1, 2, 1]); //=> [1, 2]
     *      R.uniq([1, '1']);     //=> [1, '1']
     *      R.uniq([[42], [42]]); //=> [[42]]
     */
    var uniq = uniqWith(equals);

    /**
     * Returns a new list by pulling every item at the first level of nesting out, and putting
     * them in a new array.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [b]
     * @param {Array} list The array to consider.
     * @return {Array} The flattened list.
     * @example
     *
     *      R.unnest([1, [2], [[3]]]); //=> [1, 2, [3]]
     *      R.unnest([[1, 2], [3, 4], [5, 6]]); //=> [1, 2, 3, 4, 5, 6]
     */
    var unnest = _curry1(_makeFlat(false));

    /**
     * Takes a spec object and a test object; returns true if the test satisfies
     * the spec, false otherwise. An object satisfies the spec if, for each of the
     * spec's own properties, accessing that property of the object gives the same
     * value (in `R.equals` terms) as accessing that property of the spec.
     *
     * `whereEq` is a specialization of [`where`](#where).
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig {String: *} -> {String: *} -> Boolean
     * @param {Object} spec
     * @param {Object} testObj
     * @return {Boolean}
     * @see R.where
     * @example
     *
     *      // pred :: Object -> Boolean
     *      var pred = R.whereEq({a: 1, b: 2});
     *
     *      pred({a: 1});              //=> false
     *      pred({a: 1, b: 2});        //=> true
     *      pred({a: 1, b: 2, c: 3});  //=> true
     *      pred({a: 1, b: 1});        //=> false
     */
    var whereEq = _curry2(function whereEq(spec, testObj) {
        return where(mapObj(equals, spec), testObj);
    });

    /**
     * Wrap a function inside another to allow you to make adjustments to the parameters, or do
     * other processing either before the internal function is called or with its results.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (a... -> b) -> ((a... -> b) -> a... -> c) -> (a... -> c)
     * @param {Function} fn The function to wrap.
     * @param {Function} wrapper The wrapper function.
     * @return {Function} The wrapped function.
     * @example
     *
     *      var greet = function(name) {return 'Hello ' + name;};
     *
     *      var shoutedGreet = R.wrap(greet, function(gr, name) {
     *        return gr(name).toUpperCase();
     *      });
     *      shoutedGreet("Kathy"); //=> "HELLO KATHY"
     *
     *      var shortenedGreet = R.wrap(greet, function(gr, name) {
     *        return gr(name.substring(0, 3));
     *      });
     *      shortenedGreet("Robert"); //=> "Hello Rob"
     */
    var wrap = _curry2(function wrap(fn, wrapper) {
        return curryN(fn.length, function () {
            return wrapper.apply(this, _concat([fn], arguments));
        });
    });

    var _chain = _curry2(function _chain(f, list) {
        return unnest(map(f, list));
    });

    var _flatCat = function () {
        var preservingReduced = function (xf) {
            return {
                '@@transducer/init': _xfBase.init,
                '@@transducer/result': function (result) {
                    return xf['@@transducer/result'](result);
                },
                '@@transducer/step': function (result, input) {
                    var ret = xf['@@transducer/step'](result, input);
                    return ret['@@transducer/reduced'] ? _forceReduced(ret) : ret;
                }
            };
        };
        return function _xcat(xf) {
            var rxf = preservingReduced(xf);
            return {
                '@@transducer/init': _xfBase.init,
                '@@transducer/result': function (result) {
                    return rxf['@@transducer/result'](result);
                },
                '@@transducer/step': function (result, input) {
                    return !isArrayLike(input) ? _reduce(rxf, result, [input]) : _reduce(rxf, result, input);
                }
            };
        };
    }();

    var _indexOf = function _indexOf(list, item, from) {
        var idx = 0, len = list.length;
        if (typeof from === 'number') {
            idx = from < 0 ? Math.max(0, len + from) : from;
        }
        while (idx < len) {
            if (equals(list[idx], item)) {
                return idx;
            }
            idx += 1;
        }
        return -1;
    };

    var _lastIndexOf = function _lastIndexOf(list, item, from) {
        var idx;
        if (typeof from === 'number') {
            idx = from < 0 ? list.length + from : Math.min(list.length - 1, from);
        } else {
            idx = list.length - 1;
        }
        while (idx >= 0) {
            if (equals(list[idx], item)) {
                return idx;
            }
            idx -= 1;
        }
        return -1;
    };

    var _pluck = function _pluck(p, list) {
        return map(prop(p), list);
    };

    /**
     * Create a predicate wrapper which will call a pick function (all/any) for each predicate
     *
     * @private
     * @see R.all
     * @see R.any
     */
    // Call function immediately if given arguments
    // Return a function which will call the predicates with the provided arguments
    var _predicateWrap = function _predicateWrap(predPicker) {
        return function (preds) {
            var predIterator = function () {
                var args = arguments;
                return predPicker(function (predicate) {
                    return predicate.apply(null, args);
                }, preds);
            };
            return arguments.length > 1 ? // Call function immediately if given arguments
            predIterator.apply(null, _slice(arguments, 1)) : // Return a function which will call the predicates with the provided arguments
            arity(max(_pluck('length', preds)), predIterator);
        };
    };

    var _stepCat = function () {
        var _stepCatArray = {
            '@@transducer/init': Array,
            '@@transducer/step': function (xs, x) {
                return _concat(xs, [x]);
            },
            '@@transducer/result': _identity
        };
        var _stepCatString = {
            '@@transducer/init': String,
            '@@transducer/step': _add,
            '@@transducer/result': _identity
        };
        var _stepCatObject = {
            '@@transducer/init': Object,
            '@@transducer/step': function (result, input) {
                return merge(result, isArrayLike(input) ? _createMapEntry(input[0], input[1]) : input);
            },
            '@@transducer/result': _identity
        };
        return function _stepCat(obj) {
            if (_isTransformer(obj)) {
                return obj;
            }
            if (isArrayLike(obj)) {
                return _stepCatArray;
            }
            if (typeof obj === 'string') {
                return _stepCatString;
            }
            if (typeof obj === 'object') {
                return _stepCatObject;
            }
            throw new Error('Cannot create transformer for ' + obj);
        };
    }();

    // Function, RegExp, user-defined types
    var _toString = function _toString(x, seen) {
        var recur = function recur(y) {
            var xs = seen.concat([x]);
            return _indexOf(xs, y) >= 0 ? '<Circular>' : _toString(y, xs);
        };
        switch (Object.prototype.toString.call(x)) {
        case '[object Arguments]':
            return '(function() { return arguments; }(' + _map(recur, x).join(', ') + '))';
        case '[object Array]':
            return '[' + _map(recur, x).join(', ') + ']';
        case '[object Boolean]':
            return typeof x === 'object' ? 'new Boolean(' + recur(x.valueOf()) + ')' : x.toString();
        case '[object Date]':
            return 'new Date(' + _quote(_toISOString(x)) + ')';
        case '[object Null]':
            return 'null';
        case '[object Number]':
            return typeof x === 'object' ? 'new Number(' + recur(x.valueOf()) + ')' : 1 / x === -Infinity ? '-0' : x.toString(10);
        case '[object String]':
            return typeof x === 'object' ? 'new String(' + recur(x.valueOf()) + ')' : _quote(x);
        case '[object Undefined]':
            return 'undefined';
        default:
            return typeof x.constructor === 'function' && x.constructor.name !== 'Object' && typeof x.toString === 'function' && x.toString() !== '[object Object]' ? x.toString() : // Function, RegExp, user-defined types
            '{' + _map(function (k) {
                return _quote(k) + ': ' + recur(x[k]);
            }, keys(x).sort()).join(', ') + '}';
        }
    };

    var _xchain = _curry2(function _xchain(f, xf) {
        return map(f, _flatCat(xf));
    });

    /**
     * Creates a new list iteration function from an existing one by adding two new parameters
     * to its callback function: the current index, and the entire list.
     *
     * This would turn, for instance, Ramda's simple `map` function into one that more closely
     * resembles `Array.prototype.map`.  Note that this will only work for functions in which
     * the iteration callback function is the first parameter, and where the list is the last
     * parameter.  (This latter might be unimportant if the list parameter is not used.)
     *
     * @func
     * @memberOf R
     * @category Function
     * @category List
     * @sig ((a ... -> b) ... -> [a] -> *) -> (a ..., Int, [a] -> b) ... -> [a] -> *)
     * @param {Function} fn A list iteration function that does not pass index/list to its callback
     * @return An altered list iteration function thats passes index/list to its callback
     * @example
     *
     *      var mapIndexed = R.addIndex(R.map);
     *      mapIndexed(function(val, idx) {return idx + '-' + val;}, ['f', 'o', 'o', 'b', 'a', 'r']);
     *      //=> ['0-f', '1-o', '2-o', '3-b', '4-a', '5-r']
     */
    var addIndex = _curry1(function (fn) {
        return curryN(fn.length, function () {
            var idx = 0;
            var origFn = arguments[0];
            var list = arguments[arguments.length - 1];
            var indexedFn = function () {
                var result = origFn.apply(this, _concat(arguments, [
                    idx,
                    list
                ]));
                idx += 1;
                return result;
            };
            return fn.apply(this, _prepend(indexedFn, _slice(arguments, 1)));
        });
    });

    /**
     * ap applies a list of functions to a list of values.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig [f] -> [a] -> [f a]
     * @param {Array} fns An array of functions
     * @param {Array} vs An array of values
     * @return {Array} An array of results of applying each of `fns` to all of `vs` in turn.
     * @example
     *
     *      R.ap([R.multiply(2), R.add(3)], [1,2,3]); //=> [2, 4, 6, 4, 5, 6]
     */
    var ap = _curry2(function ap(fns, vs) {
        return _hasMethod('ap', fns) ? fns.ap(vs) : _reduce(function (acc, fn) {
            return _concat(acc, map(fn, vs));
        }, [], fns);
    });

    /**
     * `chain` maps a function over a list and concatenates the results.
     * This implementation is compatible with the
     * Fantasy-land Chain spec, and will work with types that implement that spec.
     * `chain` is also known as `flatMap` in some libraries
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a -> [b]) -> [a] -> [b]
     * @param {Function} fn
     * @param {Array} list
     * @return {Array}
     * @example
     *
     *      var duplicate = function(n) {
     *        return [n, n];
     *      };
     *      R.chain(duplicate, [1, 2, 3]); //=> [1, 1, 2, 2, 3, 3]
     */
    var chain = _curry2(_dispatchable('chain', _xchain, _chain));

    /**
     * Turns a list of Functors into a Functor of a list, applying
     * a mapping function to the elements of the list along the way.
     *
     * @func
     * @memberOf R
     * @category List
     * @see R.commute
     * @sig Functor f => (f a -> f b) -> (x -> f x) -> [f a] -> f [b]
     * @param {Function} fn The transformation function
     * @param {Function} of A function that returns the data type to return
     * @param {Array} list An array of functors of the same type
     * @return {*}
     * @example
     *
     *      R.commuteMap(R.map(R.add(10)), R.of, [[1], [2, 3]]);   //=> [[11, 12], [11, 13]]
     *      R.commuteMap(R.map(R.add(10)), R.of, [[1, 2], [3]]);   //=> [[11, 13], [12, 13]]
     *      R.commuteMap(R.map(R.add(10)), R.of, [[1], [2], [3]]); //=> [[11, 12, 13]]
     *      R.commuteMap(R.map(R.add(10)), Maybe.of, [Just(1), Just(2), Just(3)]);   //=> Just([11, 12, 13])
     *      R.commuteMap(R.map(R.add(10)), Maybe.of, [Just(1), Just(2), Nothing()]); //=> Nothing()
     */
    var commuteMap = _curry3(function commuteMap(fn, of, list) {
        function consF(acc, ftor) {
            return ap(map(append, fn(ftor)), acc);
        }
        return _reduce(consF, of([]), list);
    });

    /**
     * Returns a curried equivalent of the provided function. The curried
     * function has two unusual capabilities. First, its arguments needn't
     * be provided one at a time. If `f` is a ternary function and `g` is
     * `R.curry(f)`, the following are equivalent:
     *
     *   - `g(1)(2)(3)`
     *   - `g(1)(2, 3)`
     *   - `g(1, 2)(3)`
     *   - `g(1, 2, 3)`
     *
     * Secondly, the special placeholder value `R.__` may be used to specify
     * "gaps", allowing partial application of any combination of arguments,
     * regardless of their positions. If `g` is as above and `_` is `R.__`,
     * the following are equivalent:
     *
     *   - `g(1, 2, 3)`
     *   - `g(_, 2, 3)(1)`
     *   - `g(_, _, 3)(1)(2)`
     *   - `g(_, _, 3)(1, 2)`
     *   - `g(_, 2)(1)(3)`
     *   - `g(_, 2)(1, 3)`
     *   - `g(_, 2)(_, 3)(1)`
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (* -> a) -> (* -> a)
     * @param {Function} fn The function to curry.
     * @return {Function} A new, curried function.
     * @see R.curryN
     * @example
     *
     *      var addFourNumbers = function(a, b, c, d) {
     *        return a + b + c + d;
     *      };
     *
     *      var curriedAddFourNumbers = R.curry(addFourNumbers);
     *      var f = curriedAddFourNumbers(1, 2);
     *      var g = f(3);
     *      g(4); //=> 10
     */
    var curry = _curry1(function curry(fn) {
        return curryN(fn.length, fn);
    });

    /**
     * Returns a list containing all but the first `n` elements of the given `list`.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * Dispatches to its second argument's `slice` method if present. As a
     * result, one may replace `[a]` with `String` in the type signature.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig Number -> [a] -> [a]
     * @param {Number} n The number of elements of `xs` to skip.
     * @param {Array} xs The collection to consider.
     * @return {Array}
     * @example
     *
     *      R.drop(1, ['foo', 'bar', 'baz']); //=> ['bar', 'baz']
     *      R.drop(2, ['foo', 'bar', 'baz']); //=> ['baz']
     *      R.drop(3, ['foo', 'bar', 'baz']); //=> []
     *      R.drop(4, ['foo', 'bar', 'baz']); //=> []
     *      R.drop(3, 'ramda');               //=> 'da'
     */
    var drop = _curry2(_dispatchable('drop', _xdrop, function drop(n, xs) {
        return slice(Math.max(0, n), Infinity, xs);
    }));

    /**
     * Returns a new list without any consecutively repeating elements. Equality is
     * determined by applying the supplied predicate two consecutive elements.
     * The first element in a series of equal element is the one being preserved.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig (a, a -> Boolean) -> [a] -> [a]
     * @param {Function} pred A predicate used to test whether two items are equal.
     * @param {Array} list The array to consider.
     * @return {Array} `list` without repeating elements.
     * @example
     *
     *      function lengthEq(x, y) { return Math.abs(x) === Math.abs(y); };
     *      var l = [1, -1, 1, 3, 4, -4, -4, -5, 5, 3, 3];
     *      R.dropRepeatsWith(lengthEq, l); //=> [1, 3, 4, -5, 3]
     */
    var dropRepeatsWith = _curry2(_dispatchable('dropRepeatsWith', _xdropRepeatsWith, function dropRepeatsWith(pred, list) {
        var result = [];
        var idx = 1;
        var len = list.length;
        if (len !== 0) {
            result[0] = list[0];
            while (idx < len) {
                if (!pred(last(result), list[idx])) {
                    result[result.length] = list[idx];
                }
                idx += 1;
            }
        }
        return result;
    }));

    /**
     * Performs a deep test on whether two items are equal.
     * Equality implies the two items are semmatically equivalent.
     * Cyclic structures are handled as expected
     * @see R.equals
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig a -> b -> Boolean
     * @param {*} a
     * @param {*} b
     * @return {Boolean}
     * @deprecated since v0.15.0
     * @example
     *
     *      var o = {};
     *      R.eqDeep(o, o); //=> true
     *      R.eqDeep(o, {}); //=> true
     *      R.eqDeep(1, 1); //=> true
     *      R.eqDeep(1, '1'); //=> false
     *
     *      var a = {}; a.v = a;
     *      var b = {}; b.v = b;
     *      R.eqDeep(a, b); //=> true
     */
    var eqDeep = equals;

    /**
     * Reports whether two objects have the same value, in `R.equals` terms,
     * for the specified property. Useful as a curried predicate.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig k -> {k: v} -> {k: v} -> Boolean
     * @param {String} prop The name of the property to compare
     * @param {Object} obj1
     * @param {Object} obj2
     * @return {Boolean}
     *
     * @example
     *
     *      var o1 = { a: 1, b: 2, c: 3, d: 4 };
     *      var o2 = { a: 10, b: 20, c: 3, d: 40 };
     *      R.eqProps('a', o1, o2); //=> false
     *      R.eqProps('c', o1, o2); //=> true
     */
    var eqProps = _curry3(function eqProps(prop, obj1, obj2) {
        return equals(obj1[prop], obj2[prop]);
    });

    /**
     * Returns a new function much like the supplied one, except that the first two arguments'
     * order is reversed.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (a -> b -> c -> ... -> z) -> (b -> a -> c -> ... -> z)
     * @param {Function} fn The function to invoke with its first two parameters reversed.
     * @return {*} The result of invoking `fn` with its first two parameters' order reversed.
     * @example
     *
     *      var mergeThree = function(a, b, c) {
     *        return ([]).concat(a, b, c);
     *      };
     *
     *      mergeThree(1, 2, 3); //=> [1, 2, 3]
     *
     *      R.flip(mergeThree)(1, 2, 3); //=> [2, 1, 3]
     */
    var flip = _curry1(function flip(fn) {
        return curry(function (a, b) {
            var args = _slice(arguments);
            args[0] = b;
            args[1] = a;
            return fn.apply(this, args);
        });
    });

    /**
     * Returns the position of the first occurrence of an item in an array,
     * or -1 if the item is not included in the array. `R.equals` is used to
     * determine equality.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> [a] -> Number
     * @param {*} target The item to find.
     * @param {Array} xs The array to search in.
     * @return {Number} the index of the target, or -1 if the target is not found.
     *
     * @example
     *
     *      R.indexOf(3, [1,2,3,4]); //=> 2
     *      R.indexOf(10, [1,2,3,4]); //=> -1
     */
    var indexOf = _curry2(function indexOf(target, xs) {
        return _hasMethod('indexOf', xs) ? xs.indexOf(target) : _indexOf(xs, target);
    });

    /**
     * Returns all but the last element of a list.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [a]
     * @param {Array} list The array to consider.
     * @return {Array} A new array containing all but the last element of the input list, or an
     *         empty list if the input list is empty.
     * @example
     *
     *      R.init(['fi', 'fo', 'fum']); //=> ['fi', 'fo']
     */
    var init = slice(0, -1);

    /**
     * Transforms the items of the list with the transducer and appends the transformed items to
     * the accumulator using an appropriate iterator function based on the accumulator type.
     *
     * The accumulator can be an array, string, object or a transformer. Iterated items will
     * be appended to arrays and concatenated to strings. Objects will be merged directly or 2-item
     * arrays will be merged as key, value pairs.
     *
     * The accumulator can also be a transformer object that provides a 2-arity reducing iterator
     * function, step, 0-arity initial value function, init, and 1-arity result extraction function
     * result. The step function is used as the iterator function in reduce. The result function is
     * used to convert the final accumulator into the return type and in most cases is R.identity.
     * The init function is used to provide the initial accumulator.
     *
     * The iteration is performed with R.reduce after initializing the transducer.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> (b -> b) -> [c] -> a
     * @param {*} acc The initial accumulator value.
     * @param {Function} xf The transducer function. Receives a transformer and returns a transformer.
     * @param {Array} list The list to iterate over.
     * @return {*} The final, accumulated value.
     * @example
     *
     *      var numbers = [1, 2, 3, 4];
     *      var transducer = R.compose(R.map(R.add(1)), R.take(2));
     *
     *      R.into([], transducer, numbers); //=> [2, 3]
     *
     *      var intoArray = R.into([]);
     *      intoArray(transducer, numbers); //=> [2, 3]
     */
    var into = _curry3(function into(acc, xf, list) {
        return _isTransformer(acc) ? _reduce(xf(acc), acc['@@transducer/init'](), list) : _reduce(xf(_stepCat(acc)), acc, list);
    });

    /**
     * Returns the result of applying `obj[methodName]` to `args`.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig String -> [*] -> Object -> *
     * @param {String} methodName
     * @param {Array} args
     * @param {Object} obj
     * @return {*}
     * @deprecated since v0.15.0
     * @example
     *
     *      //  toBinary :: Number -> String
     *      var toBinary = R.invoke('toString', [2])
     *
     *      toBinary(42); //=> '101010'
     *      toBinary(63); //=> '111111'
     */
    var invoke = curry(function invoke(methodName, args, obj) {
        return obj[methodName].apply(obj, args);
    });

    /**
     * Returns `true` if all elements are unique, in `R.equals` terms,
     * otherwise `false`.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> Boolean
     * @param {Array} list The array to consider.
     * @return {Boolean} `true` if all elements are unique, else `false`.
     * @example
     *
     *      R.isSet(['1', 1]); //=> true
     *      R.isSet([1, 1]);   //=> false
     *      R.isSet([[42], [42]]); //=> false
     */
    var isSet = _curry1(function isSet(list) {
        var len = list.length;
        var idx = 0;
        while (idx < len) {
            if (_indexOf(list, list[idx], idx + 1) >= 0) {
                return false;
            }
            idx += 1;
        }
        return true;
    });

    /**
     * Returns the position of the last occurrence of an item in
     * an array, or -1 if the item is not included in the array.
     * `R.equals` is used to determine equality.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> [a] -> Number
     * @param {*} target The item to find.
     * @param {Array} xs The array to search in.
     * @return {Number} the index of the target, or -1 if the target is not found.
     *
     * @example
     *
     *      R.lastIndexOf(3, [-1,3,3,0,1,2,3,4]); //=> 6
     *      R.lastIndexOf(10, [1,2,3,4]); //=> -1
     */
    var lastIndexOf = _curry2(function lastIndexOf(target, xs) {
        return _hasMethod('lastIndexOf', xs) ? xs.lastIndexOf(target) : _lastIndexOf(xs, target);
    });

    /**
     * "lifts" a function to be the specified arity, so that it may "map over" that many
     * lists (or other Functors).
     *
     * @func
     * @memberOf R
     * @see R.lift
     * @category Function
     * @sig Number -> (*... -> *) -> ([*]... -> [*])
     * @param {Function} fn The function to lift into higher context
     * @return {Function} The function `fn` applicable to mappable objects.
     * @example
     *
     *      var madd3 = R.liftN(3, R.curryN(3, function() {
     *        return R.reduce(R.add, 0, arguments);
     *      }));
     *      madd3([1,2,3], [1,2,3], [1]); //=> [3, 4, 5, 4, 5, 6, 5, 6, 7]
     */
    var liftN = _curry2(function liftN(arity, fn) {
        var lifted = curryN(arity, fn);
        return curryN(arity, function () {
            return _reduce(ap, map(lifted, arguments[0]), _slice(arguments, 1));
        });
    });

    /**
     * Returns the mean of the given list of numbers.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig [Number] -> Number
     * @param {Array} list
     * @return {Number}
     * @example
     *
     *      R.mean([2, 7, 9]); //=> 6
     *      R.mean([]); //=> NaN
     */
    var mean = _curry1(function mean(list) {
        return sum(list) / list.length;
    });

    /**
     * Returns the median of the given list of numbers.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig [Number] -> Number
     * @param {Array} list
     * @return {Number}
     * @example
     *
     *      R.median([2, 9, 7]); //=> 7
     *      R.median([7, 2, 10, 9]); //=> 8
     *      R.median([]); //=> NaN
     */
    var median = _curry1(function median(list) {
        var len = list.length;
        if (len === 0) {
            return NaN;
        }
        var width = 2 - len % 2;
        var idx = (len - width) / 2;
        return mean(_slice(list).sort(function (a, b) {
            return a < b ? -1 : a > b ? 1 : 0;
        }).slice(idx, idx + width));
    });

    /**
     * Merges a list of objects together into one object.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [{k: v}] -> {k: v}
     * @param {Array} list An array of objects
     * @return {Object} A merged object.
     * @see R.reduce
     * @example
     *
     *      R.mergeAll([{foo:1},{bar:2},{baz:3}]); //=> {foo:1,bar:2,baz:3}
     *      R.mergeAll([{foo:1},{foo:2},{bar:2}]); //=> {foo:2,bar:2}
     */
    var mergeAll = _curry1(function mergeAll(list) {
        return reduce(merge, {}, list);
    });

    /**
     * Returns a partial copy of an object omitting the keys specified.
     *
     * @func
     * @memberOf R
     * @category Object
     * @sig [String] -> {String: *} -> {String: *}
     * @param {Array} names an array of String property names to omit from the new object
     * @param {Object} obj The object to copy from
     * @return {Object} A new object with properties from `names` not on it.
     * @example
     *
     *      R.omit(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {b: 2, c: 3}
     */
    var omit = _curry2(function omit(names, obj) {
        var result = {};
        for (var prop in obj) {
            if (_indexOf(names, prop) < 0) {
                result[prop] = obj[prop];
            }
        }
        return result;
    });

    /**
     * Accepts as its arguments a function and any number of values and returns a function that,
     * when invoked, calls the original function with all of the values prepended to the
     * original function's arguments list. In some libraries this function is named `applyLeft`.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (a -> b -> ... -> i -> j -> ... -> m -> n) -> a -> b-> ... -> i -> (j -> ... -> m -> n)
     * @param {Function} fn The function to invoke.
     * @param {...*} [args] Arguments to prepend to `fn` when the returned function is invoked.
     * @return {Function} A new function wrapping `fn`. When invoked, it will call `fn`
     *         with `args` prepended to `fn`'s arguments list.
     * @example
     *
     *      var multiply = function(a, b) { return a * b; };
     *      var double = R.partial(multiply, 2);
     *      double(2); //=> 4
     *
     *      var greet = function(salutation, title, firstName, lastName) {
     *        return salutation + ', ' + title + ' ' + firstName + ' ' + lastName + '!';
     *      };
     *      var sayHello = R.partial(greet, 'Hello');
     *      var sayHelloToMs = R.partial(sayHello, 'Ms.');
     *      sayHelloToMs('Jane', 'Jones'); //=> 'Hello, Ms. Jane Jones!'
     */
    var partial = curry(_createPartialApplicator(_concat));

    /**
     * Accepts as its arguments a function and any number of values and returns a function that,
     * when invoked, calls the original function with all of the values appended to the original
     * function's arguments list.
     *
     * Note that `partialRight` is the opposite of `partial`: `partialRight` fills `fn`'s arguments
     * from the right to the left.  In some libraries this function is named `applyRight`.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (a -> b-> ... -> i -> j -> ... -> m -> n) -> j -> ... -> m -> n -> (a -> b-> ... -> i)
     * @param {Function} fn The function to invoke.
     * @param {...*} [args] Arguments to append to `fn` when the returned function is invoked.
     * @return {Function} A new function wrapping `fn`. When invoked, it will call `fn` with
     *         `args` appended to `fn`'s arguments list.
     * @example
     *
     *      var greet = function(salutation, title, firstName, lastName) {
     *        return salutation + ', ' + title + ' ' + firstName + ' ' + lastName + '!';
     *      };
     *      var greetMsJaneJones = R.partialRight(greet, 'Ms.', 'Jane', 'Jones');
     *
     *      greetMsJaneJones('Hello'); //=> 'Hello, Ms. Jane Jones!'
     */
    var partialRight = curry(_createPartialApplicator(flip(_concat)));

    /**
     * Returns a new list by plucking the same named property off all objects in the list supplied.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig k -> [{k: v}] -> [v]
     * @param {Number|String} key The key name to pluck off of each object.
     * @param {Array} list The array to consider.
     * @return {Array} The list of values for the given key.
     * @example
     *
     *      R.pluck('a')([{a: 1}, {a: 2}]); //=> [1, 2]
     *      R.pluck(0)([[1, 2], [3, 4]]);   //=> [1, 3]
     */
    var pluck = _curry2(_pluck);

    /**
     * Multiplies together all the elements of a list.
     *
     * @func
     * @memberOf R
     * @category Math
     * @sig [Number] -> Number
     * @param {Array} list An array of numbers
     * @return {Number} The product of all the numbers in the list.
     * @see R.reduce
     * @example
     *
     *      R.product([2,4,6,8,100,1]); //=> 38400
     */
    var product = reduce(_multiply, 1);

    /**
     * Returns the string representation of the given value. `eval`'ing the output
     * should result in a value equivalent to the input value. Many of the built-in
     * `toString` methods do not satisfy this requirement.
     *
     * If the given value is an `[object Object]` with a `toString` method other
     * than `Object.prototype.toString`, this method is invoked with no arguments
     * to produce the return value. This means user-defined constructor functions
     * can provide a suitable `toString` method. For example:
     *
     *     function Point(x, y) {
     *       this.x = x;
     *       this.y = y;
     *     }
     *
     *     Point.prototype.toString = function() {
     *       return 'new Point(' + this.x + ', ' + this.y + ')';
     *     };
     *
     *     R.toString(new Point(1, 2)); //=> 'new Point(1, 2)'
     *
     * @func
     * @memberOf R
     * @category String
     * @sig * -> String
     * @param {*} val
     * @return {String}
     * @example
     *
     *      R.toString(42); //=> '42'
     *      R.toString('abc'); //=> '"abc"'
     *      R.toString([1, 2, 3]); //=> '[1, 2, 3]'
     *      R.toString({foo: 1, bar: 2, baz: 3}); //=> '{"bar": 2, "baz": 3, "foo": 1}'
     *      R.toString(new Date('2001-02-03T04:05:06Z')); //=> 'new Date("2001-02-03T04:05:06.000Z")'
     */
    var toString = _curry1(function toString(val) {
        return _toString(val, []);
    });

    /**
     * Combines two lists into a set (i.e. no duplicates) composed of the
     * elements of each list.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig [a] -> [a] -> [a]
     * @param {Array} as The first list.
     * @param {Array} bs The second list.
     * @return {Array} The first and second lists concatenated, with
     *         duplicates removed.
     * @example
     *
     *      R.union([1, 2, 3], [2, 3, 4]); //=> [1, 2, 3, 4]
     */
    var union = _curry2(compose(uniq, _concat));

    /**
     * Accepts a function `fn` and any number of transformer functions and returns a new
     * function. When the new function is invoked, it calls the function `fn` with parameters
     * consisting of the result of calling each supplied handler on successive arguments to the
     * new function.
     *
     * If more arguments are passed to the returned function than transformer functions, those
     * arguments are passed directly to `fn` as additional parameters. If you expect additional
     * arguments that don't need to be transformed, although you can ignore them, it's best to
     * pass an identity function so that the new function reports the correct arity.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (x1 -> x2 -> ... -> z) -> ((a -> x1), (b -> x2), ...) -> (a -> b -> ... -> z)
     * @param {Function} fn The function to wrap.
     * @param {...Function} transformers A variable number of transformer functions
     * @return {Function} The wrapped function.
     * @example
     *
     *      // Example 1:
     *
     *      // Number -> [Person] -> [Person]
     *      var byAge = R.useWith(R.filter, R.propEq('age'), R.identity);
     *
     *      var kids = [
     *        {name: 'Abbie', age: 6},
     *        {name: 'Brian', age: 5},
     *        {name: 'Chris', age: 6},
     *        {name: 'David', age: 4},
     *        {name: 'Ellie', age: 5}
     *      ];
     *
     *      byAge(5, kids); //=> [{name: 'Brian', age: 5}, {name: 'Ellie', age: 5}]
     *
     *      // Example 2:
     *
     *      var double = function(y) { return y * 2; };
     *      var square = function(x) { return x * x; };
     *      var add = function(a, b) { return a + b; };
     *      // Adds any number of arguments together
     *      var addAll = function() {
     *        return R.reduce(add, 0, arguments);
     *      };
     *
     *      // Basic example
     *      var addDoubleAndSquare = R.useWith(addAll, double, square);
     *
     *      //≅ addAll(double(10), square(5));
     *      addDoubleAndSquare(10, 5); //=> 45
     *
     *      // Example of passing more arguments than transformers
     *      //≅ addAll(double(10), square(5), 100);
     *      addDoubleAndSquare(10, 5, 100); //=> 145
     *
     *      // If there are extra _expected_ arguments that don't need to be transformed, although
     *      // you can ignore them, it might be best to pass in the identity function so that the new
     *      // function correctly reports arity.
     *      var addDoubleAndSquareWithExtraParams = R.useWith(addAll, double, square, R.identity);
     *      // addDoubleAndSquareWithExtraParams.length //=> 3
     *      //≅ addAll(double(10), square(5), R.identity(100));
     *      addDoubleAndSquare(10, 5, 100); //=> 145
     */
    /*, transformers */
    var useWith = curry(function useWith(fn) {
        var transformers = _slice(arguments, 1);
        var tlen = transformers.length;
        return curry(arity(tlen, function () {
            var args = [], idx = 0;
            while (idx < tlen) {
                args[idx] = transformers[idx](arguments[idx]);
                idx += 1;
            }
            return fn.apply(this, args.concat(_slice(arguments, tlen)));
        }));
    });

    var _contains = function _contains(a, list) {
        return _indexOf(list, a) >= 0;
    };

    /**
     * Given a list of predicates, returns a new predicate that will be true exactly when all of them are.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig [(*... -> Boolean)] -> (*... -> Boolean)
     * @param {Array} list An array of predicate functions
     * @param {*} optional Any arguments to pass into the predicates
     * @return {Function} a function that applies its arguments to each of
     *         the predicates, returning `true` if all are satisfied.
     * @example
     *
     *      var gt10 = function(x) { return x > 10; };
     *      var even = function(x) { return x % 2 === 0};
     *      var f = R.allPass([gt10, even]);
     *      f(11); //=> false
     *      f(12); //=> true
     */
    var allPass = curry(_predicateWrap(_all));

    /**
     * Given a list of predicates returns a new predicate that will be true exactly when any one of them is.
     *
     * @func
     * @memberOf R
     * @category Logic
     * @sig [(*... -> Boolean)] -> (*... -> Boolean)
     * @param {Array} list An array of predicate functions
     * @param {*} optional Any arguments to pass into the predicates
     * @return {Function} A function that applies its arguments to each of the predicates, returning
     *         `true` if all are satisfied.
     * @example
     *
     *      var gt10 = function(x) { return x > 10; };
     *      var even = function(x) { return x % 2 === 0};
     *      var f = R.anyPass([gt10, even]);
     *      f(11); //=> true
     *      f(8); //=> true
     *      f(9); //=> false
     */
    var anyPass = curry(_predicateWrap(_any));

    /**
     * Returns the result of calling its first argument with the remaining
     * arguments. This is occasionally useful as a converging function for
     * `R.converge`: the left branch can produce a function while the right
     * branch produces a value to be passed to that function as an argument.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (*... -> a),*... -> a
     * @param {Function} fn The function to apply to the remaining arguments.
     * @param {...*} args Any number of positional arguments.
     * @return {*}
     * @example
     *
     *      var indentN = R.pipe(R.times(R.always(' ')),
     *                           R.join(''),
     *                           R.replace(/^(?!$)/gm));
     *
     *      var format = R.converge(R.call,
     *                              R.pipe(R.prop('indent'), indentN),
     *                              R.prop('value'));
     *
     *      format({indent: 2, value: 'foo\nbar\nbaz\n'}); //=> '  foo\n  bar\n  baz\n'
     */
    var call = curry(function call(fn) {
        return fn.apply(this, _slice(arguments, 1));
    });

    /**
     * Turns a list of Functors into a Functor of a list.
     *
     * @func
     * @memberOf R
     * @category List
     * @see R.commuteMap
     * @sig Functor f => (x -> f x) -> [f a] -> f [a]
     * @param {Function} of A function that returns the data type to return
     * @param {Array} list An array of functors of the same type
     * @return {*}
     * @example
     *
     *      R.commute(R.of, [[1], [2, 3]]);   //=> [[1, 2], [1, 3]]
     *      R.commute(R.of, [[1, 2], [3]]);   //=> [[1, 3], [2, 3]]
     *      R.commute(R.of, [[1], [2], [3]]); //=> [[1, 2, 3]]
     *      R.commute(Maybe.of, [Just(1), Just(2), Just(3)]);   //=> Just([1, 2, 3])
     *      R.commute(Maybe.of, [Just(1), Just(2), Nothing()]); //=> Nothing()
     */
    var commute = commuteMap(map(identity));

    /**
     * Wraps a constructor function inside a curried function that can be called with the same
     * arguments and returns the same type. The arity of the function returned is specified
     * to allow using variadic constructor functions.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig Number -> (* -> {*}) -> (* -> {*})
     * @param {Number} n The arity of the constructor function.
     * @param {Function} Fn The constructor function to wrap.
     * @return {Function} A wrapped, curried constructor function.
     * @example
     *
     *      // Variadic constructor function
     *      var Widget = function() {
     *        this.children = Array.prototype.slice.call(arguments);
     *        // ...
     *      };
     *      Widget.prototype = {
     *        // ...
     *      };
     *      var allConfigs = [
     *        // ...
     *      ];
     *      R.map(R.constructN(1, Widget), allConfigs); // a list of Widgets
     */
    var constructN = _curry2(function constructN(n, Fn) {
        if (n > 10) {
            throw new Error('Constructor with greater than ten arguments');
        }
        if (n === 0) {
            return function () {
                return new Fn();
            };
        }
        return curry(nAry(n, function ($0, $1, $2, $3, $4, $5, $6, $7, $8, $9) {
            switch (arguments.length) {
            case 1:
                return new Fn($0);
            case 2:
                return new Fn($0, $1);
            case 3:
                return new Fn($0, $1, $2);
            case 4:
                return new Fn($0, $1, $2, $3);
            case 5:
                return new Fn($0, $1, $2, $3, $4);
            case 6:
                return new Fn($0, $1, $2, $3, $4, $5);
            case 7:
                return new Fn($0, $1, $2, $3, $4, $5, $6);
            case 8:
                return new Fn($0, $1, $2, $3, $4, $5, $6, $7);
            case 9:
                return new Fn($0, $1, $2, $3, $4, $5, $6, $7, $8);
            case 10:
                return new Fn($0, $1, $2, $3, $4, $5, $6, $7, $8, $9);
            }
        }));
    });

    /**
     * Returns `true` if the specified value is equal, in `R.equals` terms,
     * to at least one element of the given list; `false` otherwise.
     *
     * @func
     * @memberOf R
     * @category List
     * @sig a -> [a] -> Boolean
     * @param {Object} a The item to compare against.
     * @param {Array} list The array to consider.
     * @return {Boolean} `true` if the item is in the list, `false` otherwise.
     *
     * @example
     *
     *      R.contains(3, [1, 2, 3]); //=> true
     *      R.contains(4, [1, 2, 3]); //=> false
     *      R.contains([42], [[42]]); //=> true
     */
    var contains = _curry2(_contains);

    /**
     * Accepts at least three functions and returns a new function. When invoked, this new
     * function will invoke the first function, `after`, passing as its arguments the
     * results of invoking the subsequent functions with whatever arguments are passed to
     * the new function.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (x1 -> x2 -> ... -> z) -> ((a -> b -> ... -> x1), (a -> b -> ... -> x2), ...) -> (a -> b -> ... -> z)
     * @param {Function} after A function. `after` will be invoked with the return values of
     *        `fn1` and `fn2` as its arguments.
     * @param {...Function} functions A variable number of functions.
     * @return {Function} A new function.
     * @example
     *
     *      var add = function(a, b) { return a + b; };
     *      var multiply = function(a, b) { return a * b; };
     *      var subtract = function(a, b) { return a - b; };
     *
     *      //≅ multiply( add(1, 2), subtract(1, 2) );
     *      R.converge(multiply, add, subtract)(1, 2); //=> -3
     *
     *      var add3 = function(a, b, c) { return a + b + c; };
     *      R.converge(add3, multiply, add, subtract)(1, 2); //=> 4
     */
    var converge = curryN(3, function (after) {
        var fns = _slice(arguments, 1);
        return curryN(max(pluck('length', fns)), function () {
            var args = arguments;
            var context = this;
            return after.apply(context, _map(function (fn) {
                return fn.apply(context, args);
            }, fns));
        });
    });

    /**
     * Finds the set (i.e. no duplicates) of all elements in the first list not contained in the second list.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig [a] -> [a] -> [a]
     * @param {Array} list1 The first list.
     * @param {Array} list2 The second list.
     * @return {Array} The elements in `list1` that are not in `list2`.
     * @see R.differenceWith
     * @example
     *
     *      R.difference([1,2,3,4], [7,6,5,4,3]); //=> [1,2]
     *      R.difference([7,6,5,4,3], [1,2,3,4]); //=> [7,6,5]
     */
    var difference = _curry2(function difference(first, second) {
        var out = [];
        var idx = 0;
        var firstLen = first.length;
        while (idx < firstLen) {
            if (!_contains(first[idx], second) && !_contains(first[idx], out)) {
                out[out.length] = first[idx];
            }
            idx += 1;
        }
        return out;
    });

    /**
     * Returns a new list without any consecutively repeating elements.
     * `R.equals` is used to determine equality.
     *
     * Acts as a transducer if a transformer is given in list position.
     * @see R.transduce
     *
     * @func
     * @memberOf R
     * @category List
     * @sig [a] -> [a]
     * @param {Array} list The array to consider.
     * @return {Array} `list` without repeating elements.
     * @example
     *
     *     R.dropRepeats([1, 1, 1, 2, 3, 4, 4, 2, 2]); //=> [1, 2, 3, 4, 2]
     */
    var dropRepeats = _curry1(_dispatchable('dropRepeats', _xdropRepeatsWith(equals), dropRepeatsWith(equals)));

    /**
     * Combines two lists into a set (i.e. no duplicates) composed of those elements common to both lists.
     *
     * @func
     * @memberOf R
     * @category Relation
     * @sig [a] -> [a] -> [a]
     * @param {Array} list1 The first list.
     * @param {Array} list2 The second list.
     * @see R.intersectionWith
     * @return {Array} The list of elements found in both `list1` and `list2`.
     * @example
     *
     *      R.intersection([1,2,3,4], [7,6,5,4,3]); //=> [4, 3]
     */
    var intersection = _curry2(function intersection(list1, list2) {
        return uniq(_filter(flip(_contains)(list1), list2));
    });

    /**
     * "lifts" a function of arity > 1 so that it may "map over" an Array or
     * other Functor.
     *
     * @func
     * @memberOf R
     * @see R.liftN
     * @category Function
     * @sig (*... -> *) -> ([*]... -> [*])
     * @param {Function} fn The function to lift into higher context
     * @return {Function} The function `fn` applicable to mappable objects.
     * @example
     *
     *      var madd3 = R.lift(R.curry(function(a, b, c) {
     *        return a + b + c;
     *      }));
     *      madd3([1,2,3], [1,2,3], [1]); //=> [3, 4, 5, 4, 5, 6, 5, 6, 7]
     *
     *      var madd5 = R.lift(R.curry(function(a, b, c, d, e) {
     *        return a + b + c + d + e;
     *      }));
     *      madd5([1,2], [3], [4, 5], [6], [7, 8]); //=> [21, 22, 22, 23, 22, 23, 23, 24]
     */
    var lift = _curry1(function lift(fn) {
        return liftN(fn.length, fn);
    });

    /**
     * Creates a new function that, when invoked, caches the result of calling `fn` for a given
     * argument set and returns the result. Subsequent calls to the memoized `fn` with the same
     * argument set will not result in an additional call to `fn`; instead, the cached result
     * for that set of arguments will be returned.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (*... -> a) -> (*... -> a)
     * @param {Function} fn The function to memoize.
     * @return {Function} Memoized version of `fn`.
     * @example
     *
     *      var count = 0;
     *      var factorial = R.memoize(function(n) {
     *        count += 1;
     *        return R.product(R.range(1, n + 1));
     *      });
     *      factorial(5); //=> 120
     *      factorial(5); //=> 120
     *      factorial(5); //=> 120
     *      count; //=> 1
     */
    var memoize = _curry1(function memoize(fn) {
        var cache = {};
        return function () {
            var key = toString(arguments);
            if (!_has(key, cache)) {
                cache[key] = fn.apply(this, arguments);
            }
            return cache[key];
        };
    });

    /**
     * Reasonable analog to SQL `select` statement.
     *
     * @func
     * @memberOf R
     * @category Object
     * @category Relation
     * @sig [k] -> [{k: v}] -> [{k: v}]
     * @param {Array} props The property names to project
     * @param {Array} objs The objects to query
     * @return {Array} An array of objects with just the `props` properties.
     * @example
     *
     *      var abby = {name: 'Abby', age: 7, hair: 'blond', grade: 2};
     *      var fred = {name: 'Fred', age: 12, hair: 'brown', grade: 7};
     *      var kids = [abby, fred];
     *      R.project(['name', 'grade'], kids); //=> [{name: 'Abby', grade: 2}, {name: 'Fred', grade: 7}]
     */
    // passing `identity` gives correct arity
    var project = useWith(_map, pickAll, identity);

    /**
     * Wraps a constructor function inside a curried function that can be called with the same
     * arguments and returns the same type.
     *
     * @func
     * @memberOf R
     * @category Function
     * @sig (* -> {*}) -> (* -> {*})
     * @param {Function} Fn The constructor function to wrap.
     * @return {Function} A wrapped, curried constructor function.
     * @example
     *
     *      // Constructor function
     *      var Widget = function(config) {
     *        // ...
     *      };
     *      Widget.prototype = {
     *        // ...
     *      };
     *      var allConfigs = [
     *        // ...
     *      ];
     *      R.map(R.construct(Widget), allConfigs); // a list of Widgets
     */
    var construct = _curry1(function construct(Fn) {
        return constructN(Fn.length, Fn);
    });

    var R = {
        F: F,
        T: T,
        __: __,
        add: add,
        addIndex: addIndex,
        adjust: adjust,
        all: all,
        allPass: allPass,
        always: always,
        and: and,
        any: any,
        anyPass: anyPass,
        ap: ap,
        aperture: aperture,
        append: append,
        apply: apply,
        arity: arity,
        assoc: assoc,
        assocPath: assocPath,
        binary: binary,
        bind: bind,
        both: both,
        call: call,
        chain: chain,
        clone: clone,
        commute: commute,
        commuteMap: commuteMap,
        comparator: comparator,
        complement: complement,
        compose: compose,
        composeL: composeL,
        composeP: composeP,
        concat: concat,
        cond: cond,
        construct: construct,
        constructN: constructN,
        contains: contains,
        containsWith: containsWith,
        converge: converge,
        countBy: countBy,
        createMapEntry: createMapEntry,
        curry: curry,
        curryN: curryN,
        dec: dec,
        defaultTo: defaultTo,
        difference: difference,
        differenceWith: differenceWith,
        dissoc: dissoc,
        dissocPath: dissocPath,
        divide: divide,
        drop: drop,
        dropRepeats: dropRepeats,
        dropRepeatsWith: dropRepeatsWith,
        dropWhile: dropWhile,
        either: either,
        empty: empty,
        eq: eq,
        eqDeep: eqDeep,
        eqProps: eqProps,
        equals: equals,
        evolve: evolve,
        filter: filter,
        filterIndexed: filterIndexed,
        find: find,
        findIndex: findIndex,
        findLast: findLast,
        findLastIndex: findLastIndex,
        flatten: flatten,
        flip: flip,
        forEach: forEach,
        forEachIndexed: forEachIndexed,
        fromPairs: fromPairs,
        functions: functions,
        functionsIn: functionsIn,
        groupBy: groupBy,
        gt: gt,
        gte: gte,
        has: has,
        hasIn: hasIn,
        head: head,
        identical: identical,
        identity: identity,
        ifElse: ifElse,
        inc: inc,
        indexOf: indexOf,
        init: init,
        insert: insert,
        insertAll: insertAll,
        intersection: intersection,
        intersectionWith: intersectionWith,
        intersperse: intersperse,
        into: into,
        invert: invert,
        invertObj: invertObj,
        invoke: invoke,
        invoker: invoker,
        is: is,
        isArrayLike: isArrayLike,
        isEmpty: isEmpty,
        isNil: isNil,
        isSet: isSet,
        join: join,
        keys: keys,
        keysIn: keysIn,
        last: last,
        lastIndexOf: lastIndexOf,
        length: length,
        lens: lens,
        lensIndex: lensIndex,
        lensOn: lensOn,
        lensProp: lensProp,
        lift: lift,
        liftN: liftN,
        lt: lt,
        lte: lte,
        map: map,
        mapAccum: mapAccum,
        mapAccumRight: mapAccumRight,
        mapIndexed: mapIndexed,
        mapObj: mapObj,
        mapObjIndexed: mapObjIndexed,
        match: match,
        mathMod: mathMod,
        max: max,
        maxBy: maxBy,
        mean: mean,
        median: median,
        memoize: memoize,
        merge: merge,
        mergeAll: mergeAll,
        min: min,
        minBy: minBy,
        modulo: modulo,
        multiply: multiply,
        nAry: nAry,
        negate: negate,
        none: none,
        not: not,
        nth: nth,
        nthArg: nthArg,
        nthChar: nthChar,
        nthCharCode: nthCharCode,
        of: of,
        omit: omit,
        once: once,
        or: or,
        partial: partial,
        partialRight: partialRight,
        partition: partition,
        path: path,
        pathEq: pathEq,
        pick: pick,
        pickAll: pickAll,
        pickBy: pickBy,
        pipe: pipe,
        pipeL: pipeL,
        pipeP: pipeP,
        pluck: pluck,
        prepend: prepend,
        product: product,
        project: project,
        prop: prop,
        propEq: propEq,
        propOr: propOr,
        props: props,
        range: range,
        reduce: reduce,
        reduceIndexed: reduceIndexed,
        reduceRight: reduceRight,
        reduceRightIndexed: reduceRightIndexed,
        reduced: reduced,
        reject: reject,
        rejectIndexed: rejectIndexed,
        remove: remove,
        repeat: repeat,
        replace: replace,
        reverse: reverse,
        scan: scan,
        slice: slice,
        sort: sort,
        sortBy: sortBy,
        split: split,
        strIndexOf: strIndexOf,
        strLastIndexOf: strLastIndexOf,
        substring: substring,
        substringFrom: substringFrom,
        substringTo: substringTo,
        subtract: subtract,
        sum: sum,
        tail: tail,
        take: take,
        takeWhile: takeWhile,
        tap: tap,
        test: test,
        times: times,
        toLower: toLower,
        toPairs: toPairs,
        toPairsIn: toPairsIn,
        toString: toString,
        toUpper: toUpper,
        transduce: transduce,
        trim: trim,
        type: type,
        unapply: unapply,
        unary: unary,
        uncurryN: uncurryN,
        unfold: unfold,
        union: union,
        unionWith: unionWith,
        uniq: uniq,
        uniqWith: uniqWith,
        unnest: unnest,
        update: update,
        useWith: useWith,
        values: values,
        valuesIn: valuesIn,
        where: where,
        whereEq: whereEq,
        wrap: wrap,
        xprod: xprod,
        zip: zip,
        zipObj: zipObj,
        zipWith: zipWith
    };

  /* TEST_ENTRY_POINT */

  if (typeof exports === 'object') {
    module.exports = R;
  } else if (typeof define === 'function' && define.amd) {
    define(function() { return R; });
  } else {
    this.R = R;
  }

}.call(this));