diff options
Diffstat (limited to 'includes/js/dojox/lang/functional/fold.js')
-rw-r--r-- | includes/js/dojox/lang/functional/fold.js | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/includes/js/dojox/lang/functional/fold.js b/includes/js/dojox/lang/functional/fold.js new file mode 100644 index 0000000..90a9a3d --- /dev/null +++ b/includes/js/dojox/lang/functional/fold.js @@ -0,0 +1,87 @@ +if(!dojo._hasResource["dojox.lang.functional.fold"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code. +dojo._hasResource["dojox.lang.functional.fold"] = true; +dojo.provide("dojox.lang.functional.fold"); + +dojo.require("dojox.lang.functional.lambda"); + +// This module adds high-level functions and related constructs: +// - "fold" family of functions + +// Notes: +// - missing high-level functions are provided with the compatible API: +// foldl, foldl1, foldr, foldr1 +// - missing JS standard functions are provided with the compatible API: +// reduce, reduceRight + +// Defined methods: +// - take any valid lambda argument as the functional argument +// - operate on dense arrays +// - take a string as the array argument +// - take an iterator objects as the array argument (only foldl, foldl1, and reduce) + +(function(){ + var d = dojo, df = dojox.lang.functional; + + d.mixin(df, { + // classic reduce-class functions + foldl: function(/*Array|String|Object*/ a, /*Function*/ f, /*Object*/ z, /*Object?*/ o){ + // summary: repeatedly applies a binary function to an array from left + // to right using a seed value as a starting point; returns the final + // value. + if(typeof a == "string"){ a = a.split(""); } + o = o || d.global; f = df.lambda(f); + if(d.isArray(a)){ + for(var i = 0, n = a.length; i < n; z = f.call(o, z, a[i], i, a), ++i); + }else{ + for(var i = 0; a.hasNext(); z = f.call(o, z, a.next(), i++)); + } + return z; // Object + }, + foldl1: function(/*Array|String|Object*/ a, /*Function|String|Array*/ f, /*Object?*/ o){ + // summary: repeatedly applies a binary function to an array from left + // to right; returns the final value. + if(typeof a == "string"){ a = a.split(""); } + o = o || d.global; f = df.lambda(f); + var z; + if(d.isArray(a)){ + z = a[0]; + for(var i = 1, n = a.length; i < n; z = f.call(o, z, a[i], i, a), ++i); + }else if(a.hasNext()){ + z = a.next(); + for(var i = 1; a.hasNext(); z = f.call(o, z, a.next(), i++)); + } + return z; // Object + }, + foldr: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object*/ z, /*Object?*/ o){ + // summary: repeatedly applies a binary function to an array from right + // to left using a seed value as a starting point; returns the final + // value. + if(typeof a == "string"){ a = a.split(""); } + o = o || d.global; f = df.lambda(f); + for(var i = a.length; i > 0; --i, z = f.call(o, z, a[i], i, a)); + return z; // Object + }, + foldr1: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){ + // summary: repeatedly applies a binary function to an array from right + // to left; returns the final value. + if(typeof a == "string"){ a = a.split(""); } + o = o || d.global; f = df.lambda(f); + var n = a.length, z = a[n - 1]; + for(var i = n - 1; i > 0; --i, z = f.call(o, z, a[i], i, a)); + return z; // Object + }, + // JS 1.8 standard array functions, which can take a lambda as a parameter. + reduce: function(/*Array|String|Object*/ a, /*Function*/ f, /*Object?*/ z){ + // summary: apply a function simultaneously against two values of the array + // (from left-to-right) as to reduce it to a single value. + return arguments.length < 3 ? df.foldl1(a, f) : df.foldl(a, f, z); // Object + }, + reduceRight: function(/*Array|String*/ a, /*Function*/ f, /*Object?*/ z){ + // summary: apply a function simultaneously against two values of the array + // (from right-to-left) as to reduce it to a single value. + return arguments.length < 3 ? df.foldr1(a, f) : df.foldr(a, f, z); // Object + } + }); +})(); + +} |