issue #1593: add POW() AQL function

CHANGELOG

@@ -1,6 +1,8 @@
 v2.8.0 (XXXX-XX-XX)
 -------------------
 
+* issue #1593: added AQL `POW` function for exponentation
+
 * added cluster execution site info in explain output for AQL queries
 
 * replication improvements:

arangod/Aql/Executor.cpp

@@ -149,6 +149,7 @@ std::unordered_map<std::string, Function const> const Executor::FunctionNames{
   { "ABS",                         Function("ABS",                         "AQL_ABS", "n", true, true, false, true, true, &Functions::Abs) },
   { "RAND",                        Function("RAND",                        "AQL_RAND", "", false, false, false, true, true, &Functions::Rand) },
   { "SQRT",                        Function("SQRT",                        "AQL_SQRT", "n", true, true, false, true, true, &Functions::Sqrt) },
+  { "POW",                         Function("POW",                         "AQL_POW", "n,n", true, true, false, true, true, &Functions::Pow) },
   
   // list functions
   { "RANGE",                       Function("RANGE",                       "AQL_RANGE", "n,n|n", true, true, false, true, true, &Functions::Range) },

arangod/Aql/Functions.cpp

@@ -3486,9 +3486,38 @@ AqlValue Functions::Sqrt (triagens::aql::Query* query,
   bool unused = false;
   double input = TRI_ToDoubleJson(inputJson.json(), unused);
   input = sqrt(input);
+  if (std::isnan(input)) {
+    return AqlValue(new Json(Json::Null));
+  }
   return AqlValue(new Json(input));
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief function POW
+////////////////////////////////////////////////////////////////////////////////
+
+AqlValue Functions::Pow (triagens::aql::Query* query,
+                         triagens::arango::AqlTransaction* trx,
+                         FunctionParameters const& parameters) {
+  size_t const n = parameters.size();
+
+  if (n != 2) {
+    THROW_ARANGO_EXCEPTION_PARAMS(TRI_ERROR_QUERY_FUNCTION_ARGUMENT_NUMBER_MISMATCH, "POW", (int) 2, (int) 2);
+  }
+
+  Json baseJson = ExtractFunctionParameter(trx, parameters, 0, false);
+  Json expJson = ExtractFunctionParameter(trx, parameters, 1, false);
+  
+  bool unused = false;
+  double base = TRI_ToDoubleJson(baseJson.json(), unused);
+  double exp = TRI_ToDoubleJson(expJson.json(), unused);
+  base = pow(base, exp);
+  if (std::isnan(base) || ! std::isfinite(base)) {
+    return AqlValue(new Json(Json::Null));
+  }
+  return AqlValue(new Json(base));
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief function RAND
 ////////////////////////////////////////////////////////////////////////////////

arangod/Aql/Functions.h

@@ -129,6 +129,7 @@ namespace triagens {
       static AqlValue Ceil                (triagens::aql::Query*, triagens::arango::AqlTransaction*, FunctionParameters const&);
       static AqlValue Floor               (triagens::aql::Query*, triagens::arango::AqlTransaction*, FunctionParameters const&);
       static AqlValue Sqrt                (triagens::aql::Query*, triagens::arango::AqlTransaction*, FunctionParameters const&);
+      static AqlValue Pow                 (triagens::aql::Query*, triagens::arango::AqlTransaction*, FunctionParameters const&);
       static AqlValue Rand                (triagens::aql::Query*, triagens::arango::AqlTransaction*, FunctionParameters const&);
       static AqlValue FirstDocument       (triagens::aql::Query*, triagens::arango::AqlTransaction*, FunctionParameters const&);
       static AqlValue FirstList           (triagens::aql::Query*, triagens::arango::AqlTransaction*, FunctionParameters const&);

js/server/modules/org/arangodb/aql.js

@@ -2767,6 +2767,16 @@ function AQL_SQRT (value) {
   return NUMERIC_VALUE(Math.sqrt(AQL_TO_NUMBER(value)));
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief exponentation
+////////////////////////////////////////////////////////////////////////////////
+
+function AQL_POW (base, exp) {
+  'use strict';
+
+  return NUMERIC_VALUE(Math.pow(AQL_TO_NUMBER(base), AQL_TO_NUMBER(exp)));
+}
+
 // -----------------------------------------------------------------------------
 // --SECTION--                                         list processing functions
 // -----------------------------------------------------------------------------
@@ -9154,6 +9164,7 @@ exports.AQL_ROUND = AQL_ROUND;
 exports.AQL_ABS = AQL_ABS;
 exports.AQL_RAND = AQL_RAND;
 exports.AQL_SQRT = AQL_SQRT;
+exports.AQL_POW = AQL_POW;
 exports.AQL_LENGTH = AQL_LENGTH;
 exports.AQL_FIRST = AQL_FIRST;
 exports.AQL_LAST = AQL_LAST;