- Author:
- David Nickerson <david.nickerson@gmail.com>
- Date:
- 2021-09-17 15:39:51+12:00
- Desc:
- tweak html formatting
- Permanent Source URI:
- https://models.fieldml.org/workspace/a1/rawfile/c47db6b2fedb368422c7f4d5191aeb9f319ad684/dojo-presentation/js/dojo/dojox/lang/functional/scan.js
dojo.provide("dojox.lang.functional.scan");
dojo.require("dojox.lang.functional.lambda");
// This module adds high-level functions and related constructs:
// - "scan" family of functions
// Notes:
// - missing high-level functions are provided with the compatible API:
// scanl, scanl1, scanr, scanr1
// 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 scanl, and scanl1)
(function(){
var d = dojo, df = dojox.lang.functional, empty = {};
d.mixin(df, {
// classic reduce-class functions
scanl: function(/*Array|String|Object*/ a, /*Function|String|Array*/ 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 an array
// of values produced by foldl() at that point.
if(typeof a == "string"){ a = a.split(""); }
o = o || d.global; f = df.lambda(f);
var t, n;
if(d.isArray(a)){
// array
t = new Array((n = a.length) + 1);
t[0] = z;
for(var i = 0; i < n; z = f.call(o, z, a[i], i, a), t[++i] = z);
}else if(typeof a.hasNext == "function" && typeof a.next == "function"){
// iterator
t = [z];
for(var i = 0; a.hasNext(); t.push(z = f.call(o, z, a.next(), i++, a)));
}else{
// object/dictionary
t = [z];
for(var i in a){
if(i in empty){ continue; }
t.push(z = f.call(o, z, a[i], i, a));
}
}
return t; // Array
},
scanl1: 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 an array of values produced by foldl1() at that
// point.
if(typeof a == "string"){ a = a.split(""); }
o = o || d.global; f = df.lambda(f);
var t, n, z;
if(d.isArray(a)){
// array
t = new Array(n = a.length);
t[0] = z = a[0];
for(var i = 1; i < n; t[i] = z = f.call(o, z, a[i], i, a), ++i);
}else if(typeof a.hasNext == "function" && typeof a.next == "function"){
// iterator
if(a.hasNext()){
t = [z = a.next()];
for(var i = 1; a.hasNext(); t.push(z = f.call(o, z, a.next(), i++, a)));
}
}else{
// object/dictionary
var first = true;
for(var i in a){
if(i in empty){ continue; }
if(first){
t = [z = a[i]];
first = false;
}else{
t.push(z = f.call(o, z, a[i], i, a));
}
}
}
return t; // Array
},
scanr: 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 an array
// of values produced by foldr() at that point.
if(typeof a == "string"){ a = a.split(""); }
o = o || d.global; f = df.lambda(f);
var n = a.length, t = new Array(n + 1);
t[n] = z;
for(var i = n; i > 0; --i, z = f.call(o, z, a[i], i, a), t[i] = z);
return t; // Array
},
scanr1: function(/*Array|String*/ a, /*Function|String|Array*/ f, /*Object?*/ o){
// summary: repeatedly applies a binary function to an array from right
// to left; returns an array of values produced by foldr1() at that
// point.
if(typeof a == "string"){ a = a.split(""); }
o = o || d.global; f = df.lambda(f);
var n = a.length, t = new Array(n), z = a[n - 1];
t[n - 1] = z;
for(var i = n - 1; i > 0; --i, z = f.call(o, z, a[i], i, a), t[i] = z);
return t; // Array
}
});
})();
