michael@0: # This Source Code Form is subject to the terms of the Mozilla Public
michael@0: # License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0: # file, You can obtain one at http://mozilla.org/MPL/2.0/.
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * lang.js - Some missing JavaScript language features
michael@0:  */
michael@0: 
michael@0: /**
michael@0:  * Partially applies a function to a particular "this object" and zero or
michael@0:  * more arguments. The result is a new function with some arguments of the first
michael@0:  * function pre-filled and the value of |this| "pre-specified".
michael@0:  *
michael@0:  * Remaining arguments specified at call-time are appended to the pre-
michael@0:  * specified ones.
michael@0:  *
michael@0:  * Usage:
michael@0:  * var barMethBound = BindToObject(myFunction, myObj, "arg1", "arg2");
michael@0:  * barMethBound("arg3", "arg4");
michael@0:  *
michael@0:  * @param fn {string} Reference to the function to be bound
michael@0:  *
michael@0:  * @param self {object} Specifies the object which |this| should point to
michael@0:  * when the function is run. If the value is null or undefined, it will default
michael@0:  * to the global object.
michael@0:  *
michael@0:  * @returns {function} A partially-applied form of the speficied function.
michael@0:  */
michael@0: function BindToObject(fn, self, opt_args) {
michael@0:   var boundargs = fn.boundArgs_ || [];
michael@0:   boundargs = boundargs.concat(Array.slice(arguments, 2, arguments.length));
michael@0: 
michael@0:   if (fn.boundSelf_)
michael@0:     self = fn.boundSelf_;
michael@0:   if (fn.boundFn_)
michael@0:     fn = fn.boundFn_;
michael@0: 
michael@0:   var newfn = function() {
michael@0:     // Combine the static args and the new args into one big array
michael@0:     var args = boundargs.concat(Array.slice(arguments));
michael@0:     return fn.apply(self, args);
michael@0:   }
michael@0: 
michael@0:   newfn.boundArgs_ = boundargs;
michael@0:   newfn.boundSelf_ = self;
michael@0:   newfn.boundFn_ = fn;
michael@0: 
michael@0:   return newfn;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Inherit the prototype methods from one constructor into another.
michael@0:  *
michael@0:  * Usage:
michael@0:  *
michael@0:  * function ParentClass(a, b) { }
michael@0:  * ParentClass.prototype.foo = function(a) { }
michael@0:  *
michael@0:  * function ChildClass(a, b, c) {
michael@0:  *   ParentClass.call(this, a, b);
michael@0:  * }
michael@0:  *
michael@0:  * ChildClass.inherits(ParentClass);
michael@0:  *
michael@0:  * var child = new ChildClass("a", "b", "see");
michael@0:  * child.foo(); // works
michael@0:  *
michael@0:  * In addition, a superclass' implementation of a method can be invoked
michael@0:  * as follows:
michael@0:  *
michael@0:  * ChildClass.prototype.foo = function(a) {
michael@0:  *   ChildClass.superClass_.foo.call(this, a);
michael@0:  *   // other code
michael@0:  * };
michael@0:  */
michael@0: Function.prototype.inherits = function(parentCtor) {
michael@0:   var tempCtor = function(){};
michael@0:   tempCtor.prototype = parentCtor.prototype;
michael@0:   this.superClass_ = parentCtor.prototype;
michael@0:   this.prototype = new tempCtor();
michael@0: }