88 lines
3.5 KiB
JavaScript
88 lines
3.5 KiB
JavaScript
|
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
|
||
|
|
}
|
||
|
|
});
|
||
|
|
})();
|
||
|
|
|
||
|
|
}
|