source: Dev/trunk/src/client/dojo/_base/lang.js @ 485

define(["./kernel", "../has", "../sniff"], function(dojo, has){
        // module:
        //              dojo/_base/lang

        has.add("bug-for-in-skips-shadowed", function(){
                // if true, the for-in iterator skips object properties that exist in Object's prototype (IE 6 - ?)
                for(var i in {toString: 1}){
                        return 0;
                }
                return 1;
        });

        // Helper methods
        var _extraNames =
                        has("bug-for-in-skips-shadowed") ?
                                "hasOwnProperty.valueOf.isPrototypeOf.propertyIsEnumerable.toLocaleString.toString.constructor".split(".") : [],

                _extraLen = _extraNames.length,

                getProp = function(/*Array*/parts, /*Boolean*/create, /*Object*/context){
                        var p, i = 0, dojoGlobal = dojo.global;
                        if(!context){
                                if(!parts.length){
                                        return dojoGlobal;
                                }else{
                                        p = parts[i++];
                                        try{
                                                context = dojo.scopeMap[p] && dojo.scopeMap[p][1];
                                        }catch(e){}
                                        context = context || (p in dojoGlobal ? dojoGlobal[p] : (create ? dojoGlobal[p] = {} : undefined));
                                }
                        }
                        while(context && (p = parts[i++])){
                                context = (p in context ? context[p] : (create ? context[p] = {} : undefined));
                        }
                        return context; // mixed
                },

                opts = Object.prototype.toString,

                efficient = function(obj, offset, startWith){
                        return (startWith||[]).concat(Array.prototype.slice.call(obj, offset||0));
                },

                _pattern = /\{([^\}]+)\}/g;

        // Module export
        var lang = {
                // summary:
                //              This module defines Javascript language extensions.

                // _extraNames: String[]
                //              Lists property names that must be explicitly processed during for-in iteration
                //              in environments that have has("bug-for-in-skips-shadowed") true.
                _extraNames:_extraNames,

                _mixin: function(dest, source, copyFunc){
                        // summary:
                        //              Copies/adds all properties of source to dest; returns dest.
                        // dest: Object
                        //              The object to which to copy/add all properties contained in source.
                        // source: Object
                        //              The object from which to draw all properties to copy into dest.
                        // copyFunc: Function?
                        //              The process used to copy/add a property in source; defaults to the Javascript assignment operator.
                        // returns:
                        //              dest, as modified
                        // description:
                        //              All properties, including functions (sometimes termed "methods"), excluding any non-standard extensions
                        //              found in Object.prototype, are copied/added to dest. Copying/adding each particular property is
                        //              delegated to copyFunc (if any); copyFunc defaults to the Javascript assignment operator if not provided.
                        //              Notice that by default, _mixin executes a so-called "shallow copy" and aggregate types are copied/added by reference.
                        var name, s, i, empty = {};
                        for(name in source){
                                // the (!(name in empty) || empty[name] !== s) condition avoids copying properties in "source"
                                // inherited from Object.prototype.      For example, if dest has a custom toString() method,
                                // don't overwrite it with the toString() method that source inherited from Object.prototype
                                s = source[name];
                                if(!(name in dest) || (dest[name] !== s && (!(name in empty) || empty[name] !== s))){
                                        dest[name] = copyFunc ? copyFunc(s) : s;
                                }
                        }

                        if(has("bug-for-in-skips-shadowed")){
                                if(source){
                                        for(i = 0; i < _extraLen; ++i){
                                                name = _extraNames[i];
                                                s = source[name];
                                                if(!(name in dest) || (dest[name] !== s && (!(name in empty) || empty[name] !== s))){
                                                        dest[name] = copyFunc ? copyFunc(s) : s;
                                                }
                                        }
                                }
                        }

                        return dest; // Object
                },

                mixin: function(dest, sources){
                        // summary:
                        //              Copies/adds all properties of one or more sources to dest; returns dest.
                        // dest: Object
                        //              The object to which to copy/add all properties contained in source. If dest is falsy, then
                        //              a new object is manufactured before copying/adding properties begins.
                        // sources: Object...
                        //              One of more objects from which to draw all properties to copy into dest. sources are processed
                        //              left-to-right and if more than one of these objects contain the same property name, the right-most
                        //              value "wins".
                        // returns: Object
                        //              dest, as modified
                        // description:
                        //              All properties, including functions (sometimes termed "methods"), excluding any non-standard extensions
                        //              found in Object.prototype, are copied/added from sources to dest. sources are processed left to right.
                        //              The Javascript assignment operator is used to copy/add each property; therefore, by default, mixin
                        //              executes a so-called "shallow copy" and aggregate types are copied/added by reference.
                        // example:
                        //              make a shallow copy of an object
                        //      |       var copy = lang.mixin({}, source);
                        // example:
                        //              many class constructors often take an object which specifies
                        //              values to be configured on the object. In this case, it is
                        //              often simplest to call `lang.mixin` on the `this` object:
                        //      |       declare("acme.Base", null, {
                        //      |               constructor: function(properties){
                        //      |                       // property configuration:
                        //      |                       lang.mixin(this, properties);
                        //      |
                        //      |                       console.log(this.quip);
                        //      |                       //      ...
                        //      |               },
                        //      |               quip: "I wasn't born yesterday, you know - I've seen movies.",
                        //      |               // ...
                        //      |       });
                        //      |
                        //      |       // create an instance of the class and configure it
                        //      |       var b = new acme.Base({quip: "That's what it does!" });
                        // example:
                        //              copy in properties from multiple objects
                        //      |       var flattened = lang.mixin(
                        //      |               {
                        //      |                       name: "Frylock",
                        //      |                       braces: true
                        //      |               },
                        //      |               {
                        //      |                       name: "Carl Brutanananadilewski"
                        //      |               }
                        //      |       );
                        //      |
                        //      |       // will print "Carl Brutanananadilewski"
                        //      |       console.log(flattened.name);
                        //      |       // will print "true"
                        //      |       console.log(flattened.braces);

                        if(!dest){ dest = {}; }
                        for(var i = 1, l = arguments.length; i < l; i++){
                                lang._mixin(dest, arguments[i]);
                        }
                        return dest; // Object
                },

                setObject: function(name, value, context){
                        // summary:
                        //              Set a property from a dot-separated string, such as "A.B.C"
                        // description:
                        //              Useful for longer api chains where you have to test each object in
                        //              the chain, or when you have an object reference in string format.
                        //              Objects are created as needed along `path`. Returns the passed
                        //              value if setting is successful or `undefined` if not.
                        // name: String
                        //              Path to a property, in the form "A.B.C".
                        // value: anything
                        //              value or object to place at location given by name
                        // context: Object?
                        //              Optional. Object to use as root of path. Defaults to
                        //              `dojo.global`.
                        // example:
                        //              set the value of `foo.bar.baz`, regardless of whether
                        //              intermediate objects already exist:
                        //      | lang.setObject("foo.bar.baz", value);
                        // example:
                        //              without `lang.setObject`, we often see code like this:
                        //      | // ensure that intermediate objects are available
                        //      | if(!obj["parent"]){ obj.parent = {}; }
                        //      | if(!obj.parent["child"]){ obj.parent.child = {}; }
                        //      | // now we can safely set the property
                        //      | obj.parent.child.prop = "some value";
                        //              whereas with `lang.setObject`, we can shorten that to:
                        //      | lang.setObject("parent.child.prop", "some value", obj);

                        var parts = name.split("."), p = parts.pop(), obj = getProp(parts, true, context);
                        return obj && p ? (obj[p] = value) : undefined; // Object
                },

                getObject: function(name, create, context){
                        // summary:
                        //              Get a property from a dot-separated string, such as "A.B.C"
                        // description:
                        //              Useful for longer api chains where you have to test each object in
                        //              the chain, or when you have an object reference in string format.
                        // name: String
                        //              Path to an property, in the form "A.B.C".
                        // create: Boolean?
                        //              Optional. Defaults to `false`. If `true`, Objects will be
                        //              created at any point along the 'path' that is undefined.
                        // context: Object?
                        //              Optional. Object to use as root of path. Defaults to
                        //              'dojo.global'. Null may be passed.
                        return getProp(name.split("."), create, context); // Object
                },

                exists: function(name, obj){
                        // summary:
                        //              determine if an object supports a given method
                        // description:
                        //              useful for longer api chains where you have to test each object in
                        //              the chain. Useful for object and method detection.
                        // name: String
                        //              Path to an object, in the form "A.B.C".
                        // obj: Object?
                        //              Object to use as root of path. Defaults to
                        //              'dojo.global'. Null may be passed.
                        // example:
                        //      | // define an object
                        //      | var foo = {
                        //      |               bar: { }
                        //      | };
                        //      |
                        //      | // search the global scope
                        //      | lang.exists("foo.bar"); // true
                        //      | lang.exists("foo.bar.baz"); // false
                        //      |
                        //      | // search from a particular scope
                        //      | lang.exists("bar", foo); // true
                        //      | lang.exists("bar.baz", foo); // false
                        return lang.getObject(name, false, obj) !== undefined; // Boolean
                },

                // Crockford (ish) functions

                isString: function(it){
                        // summary:
                        //              Return true if it is a String
                        // it: anything
                        //              Item to test.
                        return (typeof it == "string" || it instanceof String); // Boolean
                },

                isArray: function(it){
                        // summary:
                        //              Return true if it is an Array.
                        //              Does not work on Arrays created in other windows.
                        // it: anything
                        //              Item to test.
                        return it && (it instanceof Array || typeof it == "array"); // Boolean
                },

                isFunction: function(it){
                        // summary:
                        //              Return true if it is a Function
                        // it: anything
                        //              Item to test.
                        return opts.call(it) === "[object Function]";
                },

                isObject: function(it){
                        // summary:
                        //              Returns true if it is a JavaScript object (or an Array, a Function
                        //              or null)
                        // it: anything
                        //              Item to test.
                        return it !== undefined &&
                                (it === null || typeof it == "object" || lang.isArray(it) || lang.isFunction(it)); // Boolean
                },

                isArrayLike: function(it){
                        // summary:
                        //              similar to isArray() but more permissive
                        // it: anything
                        //              Item to test.
                        // returns:
                        //              If it walks like a duck and quacks like a duck, return `true`
                        // description:
                        //              Doesn't strongly test for "arrayness".  Instead, settles for "isn't
                        //              a string or number and has a length property". Arguments objects
                        //              and DOM collections will return true when passed to
                        //              isArrayLike(), but will return false when passed to
                        //              isArray().
                        return it && it !== undefined && // Boolean
                                // keep out built-in constructors (Number, String, ...) which have length
                                // properties
                                !lang.isString(it) && !lang.isFunction(it) &&
                                !(it.tagName && it.tagName.toLowerCase() == 'form') &&
                                (lang.isArray(it) || isFinite(it.length));
                },

                isAlien: function(it){
                        // summary:
                        //              Returns true if it is a built-in function or some other kind of
                        //              oddball that *should* report as a function but doesn't
                        return it && !lang.isFunction(it) && /\{\s*\[native code\]\s*\}/.test(String(it)); // Boolean
                },

                extend: function(ctor, props){
                        // summary:
                        //              Adds all properties and methods of props to constructor's
                        //              prototype, making them available to all instances created with
                        //              constructor.
                        // ctor: Object
                        //              Target constructor to extend.
                        // props: Object
                        //              One or more objects to mix into ctor.prototype
                        for(var i=1, l=arguments.length; i<l; i++){
                                lang._mixin(ctor.prototype, arguments[i]);
                        }
                        return ctor; // Object
                },

                _hitchArgs: function(scope, method){
                        var pre = lang._toArray(arguments, 2);
                        var named = lang.isString(method);
                        return function(){
                                // arrayify arguments
                                var args = lang._toArray(arguments);
                                // locate our method
                                var f = named ? (scope||dojo.global)[method] : method;
                                // invoke with collected args
                                return f && f.apply(scope || this, pre.concat(args)); // mixed
                        }; // Function
                },

                hitch: function(scope, method){
                        // summary:
                        //              Returns a function that will only ever execute in the a given scope.
                        //              This allows for easy use of object member functions
                        //              in callbacks and other places in which the "this" keyword may
                        //              otherwise not reference the expected scope.
                        //              Any number of default positional arguments may be passed as parameters
                        //              beyond "method".
                        //              Each of these values will be used to "placehold" (similar to curry)
                        //              for the hitched function.
                        // scope: Object
                        //              The scope to use when method executes. If method is a string,
                        //              scope is also the object containing method.
                        // method: Function|String...
                        //              A function to be hitched to scope, or the name of the method in
                        //              scope to be hitched.
                        // example:
                        //      |       lang.hitch(foo, "bar")();
                        //              runs foo.bar() in the scope of foo
                        // example:
                        //      |       lang.hitch(foo, myFunction);
                        //              returns a function that runs myFunction in the scope of foo
                        // example:
                        //              Expansion on the default positional arguments passed along from
                        //              hitch. Passed args are mixed first, additional args after.
                        //      |       var foo = { bar: function(a, b, c){ console.log(a, b, c); } };
                        //      |       var fn = lang.hitch(foo, "bar", 1, 2);
                        //      |       fn(3); // logs "1, 2, 3"
                        // example:
                        //      |       var foo = { bar: 2 };
                        //      |       lang.hitch(foo, function(){ this.bar = 10; })();
                        //              execute an anonymous function in scope of foo
                        if(arguments.length > 2){
                                return lang._hitchArgs.apply(dojo, arguments); // Function
                        }
                        if(!method){
                                method = scope;
                                scope = null;
                        }
                        if(lang.isString(method)){
                                scope = scope || dojo.global;
                                if(!scope[method]){ throw(['lang.hitch: scope["', method, '"] is null (scope="', scope, '")'].join('')); }
                                return function(){ return scope[method].apply(scope, arguments || []); }; // Function
                        }
                        return !scope ? method : function(){ return method.apply(scope, arguments || []); }; // Function
                },

                delegate: (function(){
                        // boodman/crockford delegation w/ cornford optimization
                        function TMP(){}
                        return function(obj, props){
                                TMP.prototype = obj;
                                var tmp = new TMP();
                                TMP.prototype = null;
                                if(props){
                                        lang._mixin(tmp, props);
                                }
                                return tmp; // Object
                        };
                })(),
                /*=====
                delegate: function(obj, props){
                        // summary:
                        //              Returns a new object which "looks" to obj for properties which it
                        //              does not have a value for. Optionally takes a bag of properties to
                        //              seed the returned object with initially.
                        // description:
                        //              This is a small implementation of the Boodman/Crockford delegation
                        //              pattern in JavaScript. An intermediate object constructor mediates
                        //              the prototype chain for the returned object, using it to delegate
                        //              down to obj for property lookup when object-local lookup fails.
                        //              This can be thought of similarly to ES4's "wrap", save that it does
                        //              not act on types but rather on pure objects.
                        // obj: Object
                        //              The object to delegate to for properties not found directly on the
                        //              return object or in props.
                        // props: Object...
                        //              an object containing properties to assign to the returned object
                        // returns:
                        //              an Object of anonymous type
                        // example:
                        //      |       var foo = { bar: "baz" };
                        //      |       var thinger = lang.delegate(foo, { thud: "xyzzy"});
                        //      |       thinger.bar == "baz"; // delegated to foo
                        //      |       foo.thud == undefined; // by definition
                        //      |       thinger.thud == "xyzzy"; // mixed in from props
                        //      |       foo.bar = "thonk";
                        //      |       thinger.bar == "thonk"; // still delegated to foo's bar
                },
                =====*/

                _toArray: has("ie") ?
                        (function(){
                                function slow(obj, offset, startWith){
                                        var arr = startWith||[];
                                        for(var x = offset || 0; x < obj.length; x++){
                                                arr.push(obj[x]);
                                        }
                                        return arr;
                                }
                                return function(obj){
                                        return ((obj.item) ? slow : efficient).apply(this, arguments);
                                };
                        })() : efficient,
                /*=====
                 _toArray: function(obj, offset, startWith){
                         // summary:
                         //             Converts an array-like object (i.e. arguments, DOMCollection) to an
                         //             array. Returns a new Array with the elements of obj.
                         // obj: Object
                         //             the object to "arrayify". We expect the object to have, at a
                         //             minimum, a length property which corresponds to integer-indexed
                         //             properties.
                         // offset: Number?
                         //             the location in obj to start iterating from. Defaults to 0.
                         //             Optional.
                         // startWith: Array?
                         //             An array to pack with the properties of obj. If provided,
                         //             properties in obj are appended at the end of startWith and
                         //             startWith is the returned array.
                 },
                 =====*/

                partial: function(/*Function|String*/ method /*, ...*/){
                        // summary:
                        //              similar to hitch() except that the scope object is left to be
                        //              whatever the execution context eventually becomes.
                        // description:
                        //              Calling lang.partial is the functional equivalent of calling:
                        //              |       lang.hitch(null, funcName, ...);
                        // method:
                        //              The function to "wrap"
                        var arr = [ null ];
                        return lang.hitch.apply(dojo, arr.concat(lang._toArray(arguments))); // Function
                },

                clone: function(/*anything*/ src){
                        // summary:
                        //              Clones objects (including DOM nodes) and all children.
                        //              Warning: do not clone cyclic structures.
                        // src:
                        //              The object to clone
                        if(!src || typeof src != "object" || lang.isFunction(src)){
                                // null, undefined, any non-object, or function
                                return src;     // anything
                        }
                        if(src.nodeType && "cloneNode" in src){
                                // DOM Node
                                return src.cloneNode(true); // Node
                        }
                        if(src instanceof Date){
                                // Date
                                return new Date(src.getTime()); // Date
                        }
                        if(src instanceof RegExp){
                                // RegExp
                                return new RegExp(src);   // RegExp
                        }
                        var r, i, l;
                        if(lang.isArray(src)){
                                // array
                                r = [];
                                for(i = 0, l = src.length; i < l; ++i){
                                        if(i in src){
                                                r.push(lang.clone(src[i]));
                                        }
                                }
                                // we don't clone functions for performance reasons
                                //              }else if(d.isFunction(src)){
                                //                      // function
                                //                      r = function(){ return src.apply(this, arguments); };
                        }else{
                                // generic objects
                                r = src.constructor ? new src.constructor() : {};
                        }
                        return lang._mixin(r, src, lang.clone);
                },


                trim: String.prototype.trim ?
                        function(str){ return str.trim(); } :
                        function(str){ return str.replace(/^\s\s*/, '').replace(/\s\s*$/, ''); },
                /*=====
                 trim: function(str){
                         // summary:
                         //             Trims whitespace from both sides of the string
                         // str: String
                         //             String to be trimmed
                         // returns: String
                         //             Returns the trimmed string
                         // description:
                         //             This version of trim() was selected for inclusion into the base due
                         //             to its compact size and relatively good performance
                         //             (see [Steven Levithan's blog](http://blog.stevenlevithan.com/archives/faster-trim-javascript)
                         //             Uses String.prototype.trim instead, if available.
                         //             The fastest but longest version of this function is located at
                         //             lang.string.trim()
                 },
                 =====*/

                replace: function(tmpl, map, pattern){
                        // summary:
                        //              Performs parameterized substitutions on a string. Throws an
                        //              exception if any parameter is unmatched.
                        // tmpl: String
                        //              String to be used as a template.
                        // map: Object|Function
                        //              If an object, it is used as a dictionary to look up substitutions.
                        //              If a function, it is called for every substitution with following parameters:
                        //              a whole match, a name, an offset, and the whole template
                        //              string (see https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/String/replace
                        //              for more details).
                        // pattern: RegEx?
                        //              Optional regular expression objects that overrides the default pattern.
                        //              Must be global and match one item. The default is: /\{([^\}]+)\}/g,
                        //              which matches patterns like that: "{xxx}", where "xxx" is any sequence
                        //              of characters, which doesn't include "}".
                        // returns: String
                        //              Returns the substituted string.
                        // example:
                        //      |       // uses a dictionary for substitutions:
                        //      |       lang.replace("Hello, {name.first} {name.last} AKA {nick}!",
                        //      |               {
                        //      |                       nick: "Bob",
                        //      |                       name: {
                        //      |                               first:  "Robert",
                        //      |                               middle: "X",
                        //      |                               last:           "Cringely"
                        //      |                       }
                        //      |               });
                        //      |       // returns: Hello, Robert Cringely AKA Bob!
                        // example:
                        //      |       // uses an array for substitutions:
                        //      |       lang.replace("Hello, {0} {2}!",
                        //      |               ["Robert", "X", "Cringely"]);
                        //      |       // returns: Hello, Robert Cringely!
                        // example:
                        //      |       // uses a function for substitutions:
                        //      |       function sum(a){
                        //      |               var t = 0;
                        //      |               arrayforEach(a, function(x){ t += x; });
                        //      |               return t;
                        //      |       }
                        //      |       lang.replace(
                        //      |               "{count} payments averaging {avg} USD per payment.",
                        //      |               lang.hitch(
                        //      |                       { payments: [11, 16, 12] },
                        //      |                       function(_, key){
                        //      |                               switch(key){
                        //      |                                       case "count": return this.payments.length;
                        //      |                                       case "min":             return Math.min.apply(Math, this.payments);
                        //      |                                       case "max":             return Math.max.apply(Math, this.payments);
                        //      |                                       case "sum":             return sum(this.payments);
                        //      |                                       case "avg":             return sum(this.payments) / this.payments.length;
                        //      |                               }
                        //      |                       }
                        //      |               )
                        //      |       );
                        //      |       // prints: 3 payments averaging 13 USD per payment.
                        // example:
                        //      |       // uses an alternative PHP-like pattern for substitutions:
                        //      |       lang.replace("Hello, ${0} ${2}!",
                        //      |               ["Robert", "X", "Cringely"], /\$\{([^\}]+)\}/g);
                        //      |       // returns: Hello, Robert Cringely!

                        return tmpl.replace(pattern || _pattern, lang.isFunction(map) ?
                                map : function(_, k){ return lang.getObject(k, false, map); });
                }
        };

        has("extend-dojo") && lang.mixin(dojo, lang);

        return lang;
});