105 lines
3.5 KiB
JavaScript
105 lines
3.5 KiB
JavaScript
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//>>built
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define("dojox/lang/functional/scan", ["dojo/_base/kernel", "dojo/_base/lang", "./lambda"], function(d, darray, df){
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// This module adds high-level functions and related constructs:
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// - "scan" family of functions
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// Notes:
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// - missing high-level functions are provided with the compatible API:
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// scanl, scanl1, scanr, scanr1
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// Defined methods:
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// - take any valid lambda argument as the functional argument
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// - operate on dense arrays
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// - take a string as the array argument
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// - take an iterator objects as the array argument (only scanl, and scanl1)
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var empty = {};
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d.mixin(df, {
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// classic reduce-class functions
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scanl: function(/*Array|String|Object*/ a, /*Function|String|Array*/ f, /*Object*/ z, /*Object?*/ o){
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// summary: repeatedly applies a binary function to an array from left
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// to right using a seed value as a starting point; returns an array
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// of values produced by foldl() at that point.
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if(typeof a == "string"){ a = a.split(""); }
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o = o || d.global; f = df.lambda(f);
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var t, n, i;
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if(d.isArray(a)){
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// array
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t = new Array((n = a.length) + 1);
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t[0] = z;
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for(i = 0; i < n; z = f.call(o, z, a[i], i, a), t[++i] = z);
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}else if(typeof a.hasNext == "function" && typeof a.next == "function"){
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// iterator
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t = [z];
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for(i = 0; a.hasNext(); t.push(z = f.call(o, z, a.next(), i++, a)));
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}else{
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// object/dictionary
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t = [z];
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for(i in a){
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if(!(i in empty)){
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t.push(z = f.call(o, z, a[i], i, a));
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}
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}
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}
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return t; // Array
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},
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scanl1: function(/*Array|String|Object*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
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// summary: repeatedly applies a binary function to an array from left
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// to right; returns an array of values produced by foldl1() at that
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// point.
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if(typeof a == "string"){ a = a.split(""); }
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o = o || d.global; f = df.lambda(f);
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var t, n, z, first = true;
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if(d.isArray(a)){
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// array
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t = new Array(n = a.length);
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t[0] = z = a[0];
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for(var i = 1; i < n; t[i] = z = f.call(o, z, a[i], i, a), ++i);
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}else if(typeof a.hasNext == "function" && typeof a.next == "function"){
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// iterator
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if(a.hasNext()){
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t = [z = a.next()];
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for(i = 1; a.hasNext(); t.push(z = f.call(o, z, a.next(), i++, a)));
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}
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}else{
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// object/dictionary
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for(i in a){
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if(!(i in empty)){
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if(first){
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t = [z = a[i]];
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first = false;
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}else{
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t.push(z = f.call(o, z, a[i], i, a));
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}
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}
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}
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}
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return t; // Array
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},
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scanr: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object*/ z, /*Object?*/ o){
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// summary: repeatedly applies a binary function to an array from right
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// to left using a seed value as a starting point; returns an array
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// of values produced by foldr() at that point.
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if(typeof a == "string"){ a = a.split(""); }
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o = o || d.global; f = df.lambda(f);
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var n = a.length, t = new Array(n + 1), i = n;
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t[n] = z;
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for(; i > 0; --i, z = f.call(o, z, a[i], i, a), t[i] = z);
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return t; // Array
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},
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scanr1: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
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// summary: repeatedly applies a binary function to an array from right
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// to left; returns an array of values produced by foldr1() at that
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// point.
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if(typeof a == "string"){ a = a.split(""); }
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o = o || d.global; f = df.lambda(f);
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var n = a.length, t = new Array(n), z = a[n - 1], i = n - 1;
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t[i] = z;
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for(; i > 0; --i, z = f.call(o, z, a[i], i, a), t[i] = z);
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return t; // Array
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}
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});
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});
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