source: Dev/trunk/src/client/dojox/drawing/util/oo.js

define([], function(){
// TODO:
// allow a declare without a mixin

return {
        // summary:
        //              Inheritance utilities used in DojoX Drawing
        // description:
        //              Inheritance utilities used in DojoX Drawing.
        //              There were designed in a effort to make Drawing as
        //              fast as possible - especially in a case where thousands
        //              of objects are being loaded. Drawing declare performs
        //              about 3 times faster than declare and 2 times
        //              faster than Dojox declare. This is not to say Drawing
        //              declare is without limitations. It doesn't have the same
        //              syntactic sugar and extensibility of the other two. You
        //              can't inherit methods. It won't work with Dijit. But it
        //              is simple and effective.

        declare: function(){
                // summary:
                //              Creates a constructor Function from a
                //              Function, and collection of methods, and
                //              more Functions that are extended.
                // description:
                //              Similar in look and feel to declare as
                //              far as order and number of arguments, although
                //              constructed a little closer to prototypical
                //              inheritance. All arguments passed into the
                //              constructor are passed into all sub constructors.
                //
                //              Arguments are: Function, [Object|Function....]
                //              The first argument is always the base
                //              constructor. The last argument is always
                //              an object of methods (or empty object) to
                //              be mixed in (in the future would like to
                //              make that object optional). Remaining
                //              arguments are other constructors mixed in
                //              using extend() (See below).
                // example:
                //              |       MyFunction = dojox.drawing.util.oo.declare(
                //              |               MyOtherFunction,
                //              |               YetAnotherFunction,
                //              |               function(options){
                //              |                       // This is my constructor. It will fire last.
                //              |                       // The other constructors will fire before this.
                //              |               },
                //              |               {
                //              |                       customType:"equation", // mixed in property
                //              |                       doThing: function(){   // mixed in method
                //              |
                //              |                       }
                //              |               }
                //              |       );
                //              |
                //              |       var f = new MyFunction();

                var f, o, ext=0, a = arguments;
                                
                if(a.length<2){ console.error("drawing.util.oo.declare; not enough arguments")}
                if(a.length==2){
                        f = a[0]; o = a[1];
                }else{
                        a = Array.prototype.slice.call(arguments);
                        o = a.pop();
                        f = a.pop();
                        ext = 1;
                }
                for(var n in o){
                        f.prototype[n] = o[n];
                }
                if(ext){
                        a.unshift(f);
                        f = this.extend.apply(this, a);
                }
                return f; // Function
        },
        extend: function(){
                // summary:
                //              Extends constructors to inherit from other
                //              constructors .
                // description:
                //              Typically not used by itself - it's used as
                //              part of declare(). Could be used by itself
                //              however, to mix together two or more
                //              constructors.
                //
                //              Any number of arguments, all must be
                //              function constructors. The first is
                //              considered the base object and its
                //              constructor will fire first.
                // example:
                //              |       var A = function(){};
                //              |       var B = function(){};
                //              |       var C = function(){};
                //              |       var D = dojox.drawing.util.oo.extend(A, B, C);
                //              |       var e = new D();

                var a = arguments, sub = a[0];
                if(a.length<2){ console.error("drawing.util.oo.extend; not enough arguments")}
                var f = function (){
                        for(var i=1;i<a.length;i++){
                                a[i].prototype.constructor.apply(this, arguments);
                        }
                        // sub should fire last
                        sub.prototype.constructor.apply(this, arguments);
                        
                };
                for(var i=1;i<a.length;i++){
                        for(var n in a[i].prototype){
                                f.prototype[n] = a[i].prototype[n];
                        }
                }
                        
                for(n in sub.prototype){
                        f.prototype[n] = sub.prototype[n];
                }
                return f; // Function
        }
};
});