Split concrete and abstract ctor generation into two separate functions
Mike Gerwitz
parent
5bb0269280
commit
8ba68b31dc
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@ -41,7 +41,16 @@ var util = require( __dirname + '/util' ),
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* Instance id counter, to be incremented on each new instance
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* @type {number}
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*/
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instance_id = 0
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instance_id = 0,
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/**
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* Set to TRUE when class is in the process of being extended to ensure that
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* a constructor can be instantiated (to use as the prototype) without
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* invoking the class construction logic
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*
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* @type {boolean}
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*/
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extending = false
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;
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@ -71,211 +80,241 @@ var enum_bug = (
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exports.ClassBase = function Class() {};
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exports.build = ( function( extending )
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/**
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* Mimics class inheritance
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*
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* This method will mimic inheritance by setting up the prototype with the
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* provided base class (or, by default, Class) and copying the additional
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* properties atop of it.
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*
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* The class to inherit from (the first argument) is optional. If omitted, the
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* first argument will be considered to be the properties list.
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*
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* @return {Object} extended class
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*/
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exports.build = function extend()
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{
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/**
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* Mimics class inheritance
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*
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* This method will mimic inheritance by setting up the prototype with the
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* provided base class (or, by default, Class) and copying the additional
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* properties atop of it.
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*
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* The class to inherit from (the first argument) is optional. If omitted, the
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* first argument will be considered to be the properties list.
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*
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* @return {Object} extended class
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*/
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return function extend()
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// ensure we'll be permitted to instantiate abstract classes for the base
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extending = true;
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var args = Array.prototype.slice.call( arguments ),
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props = args.pop() || {},
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base = args.pop() || exports.ClassBase,
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prototype = new base(),
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cname = '',
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properties = {},
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prop_init = member_builder.initMembers(),
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members = member_builder.initMembers( prototype ),
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abstract_methods =
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util.clone( exports.getMeta( base ).abstractMethods )
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|| { __length: 0 }
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;
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// grab the name, if one was provided
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if ( cname = props.__name )
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{
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// ensure we'll be permitted to instantiate abstract classes for the base
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extending = true;
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// we no longer need it
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delete props.__name;
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}
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var args = Array.prototype.slice.call( arguments ),
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props = args.pop() || {},
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base = args.pop() || exports.ClassBase,
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prototype = new base(),
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cname = '',
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properties = {},
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prop_init = member_builder.initMembers(),
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members = member_builder.initMembers( prototype ),
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abstract_methods =
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util.clone( exports.getMeta( base ).abstractMethods )
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|| { __length: 0 }
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;
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// grab the name, if one was provided
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if ( cname = props.__name )
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{
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// we no longer need it
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delete props.__name;
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}
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// IE has problems with toString()
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if ( enum_bug )
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{
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if ( props.toString !== Object.prototype.toString )
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{
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props.__toString = props.toString;
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}
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}
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// increment class identifier
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class_id++;
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// build the various class components (xxx: this is temporary; needs
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// refactoring)
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buildMembers( props,
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class_id,
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base,
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prop_init,
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abstract_methods,
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properties,
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members,
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getMethodInstance
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);
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// reference to the parent prototype (for more experienced users)
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prototype.___$$parent$$ = base.prototype;
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// set up the new class
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var new_class = createCtor( cname, abstract_methods, members );
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attachPropInit( prototype, prop_init, members, class_id );
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new_class.prototype = prototype;
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new_class.constructor = new_class;
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new_class.___$$props$$ = prop_init;
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new_class.___$$methods$$ = members;
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// create internal metadata for the new class
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var meta = createMeta( new_class, base );
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meta.abstractMethods = abstract_methods;
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meta.name = cname;
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// we're done with the extension process
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extending = false;
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return {
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'class': new_class,
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abstractMethods: abstract_methods,
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classId: class_id,
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};
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};
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/**
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* Creates the constructor for a new class
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*
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* This constructor will call the __constructor method for concrete classes
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* and throw an exception for abstract classes (to prevent instantiation).
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*
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* @param {string} cname class name (may be empty)
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* @param {Array.<string>} abstract_methods list of abstract methods
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* @param {Object} members class members
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*
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* @return {Function} constructor
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*/
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function createCtor( cname, abstract_methods, members )
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// IE has problems with toString()
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if ( enum_bug )
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{
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// concrete class
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if ( abstract_methods.__length === 0 )
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if ( props.toString !== Object.prototype.toString )
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{
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var args = null;
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// constructor function to be returned
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var __self = function()
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{
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if ( !( this instanceof __self ) )
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{
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// store arguments to be passed to constructor and
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// instantiate new object
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args = arguments;
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return new __self();
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}
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// generate and store unique instance id
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attachInstanceId( this, ++instance_id, __self );
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initInstance( instance_id, this );
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this.__initProps();
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// call the constructor, if one was provided
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if ( this.__construct instanceof Function )
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{
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// note that since 'this' refers to the new class (even
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// subtypes), and since we're using apply with 'this', the
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// constructor will be applied to subtypes without a problem
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this.__construct.apply( this, ( args || arguments ) );
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args = null;
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}
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// attach any instance properties/methods (done after
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// constructor to ensure they are not overridden)
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attachInstanceOf( this );
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// Provide a more intuitive string representation of the class
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// instance. If a toString() method was already supplied for us,
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// use that one instead.
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if ( !( Object.prototype.hasOwnProperty.call(
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members[ 'public' ], 'toString'
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) ) )
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{
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// use __toString if available (see enum_bug), otherwise use
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// our own defaults
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this.toString = members[ 'public' ].__toString
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|| ( ( cname )
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? function()
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{
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return '#<' + cname + '>';
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}
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: function()
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{
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return '#<anonymous>';
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}
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)
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;
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}
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};
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// provide a more intuitive string representation
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__self.toString = ( cname )
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? function() { return cname; }
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: function() { return '(Class)'; }
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;
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return __self;
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}
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// abstract class
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else
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{
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var __abstract_self = function()
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{
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if ( !extending )
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{
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throw Error(
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"Abstract class " + ( cname || '(anonymous)' ) +
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" cannot be instantiated"
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);
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}
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};
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__abstract_self.toString = ( cname )
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? function()
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{
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return cname;
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}
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: function()
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{
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return '(AbstractClass)';
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}
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;
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return __abstract_self;
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props.__toString = props.toString;
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}
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}
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} )( false );
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// increment class identifier
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class_id++;
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// build the various class components (xxx: this is temporary; needs
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// refactoring)
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buildMembers( props,
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class_id,
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base,
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prop_init,
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abstract_methods,
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properties,
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members,
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getMethodInstance
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);
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// reference to the parent prototype (for more experienced users)
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prototype.___$$parent$$ = base.prototype;
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// set up the new class
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var new_class = createCtor( cname, abstract_methods, members );
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attachPropInit( prototype, prop_init, members, class_id );
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new_class.prototype = prototype;
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new_class.constructor = new_class;
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new_class.___$$props$$ = prop_init;
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new_class.___$$methods$$ = members;
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// create internal metadata for the new class
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var meta = createMeta( new_class, base );
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meta.abstractMethods = abstract_methods;
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meta.name = cname;
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// we're done with the extension process
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extending = false;
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return {
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'class': new_class,
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abstractMethods: abstract_methods,
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classId: class_id,
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};
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};
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/**
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* Creates the constructor for a new class
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*
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* This constructor will call the __constructor method for concrete classes
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* and throw an exception for abstract classes (to prevent instantiation).
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*
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* @param {string} cname class name (may be empty)
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* @param {Array.<string>} abstract_methods list of abstract methods
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* @param {Object} members class members
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*
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* @return {Function} constructor
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*/
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function createCtor( cname, abstract_methods, members )
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{
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// concrete class
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if ( abstract_methods.__length === 0 )
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{
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return createConcreteCtor( cname, members );
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}
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// abstract class
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else
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{
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return createAbstractCtor( cname );
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}
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}
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/**
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* Creates the constructor for a new concrete class
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*
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* This constructor will call the __constructor method of the class, if
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* available.
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*
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* @param {string} cname class name (may be empty)
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* @param {Object} members class members
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*
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* @return {function()} constructor
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*/
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function createConcreteCtor( cname, members )
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{
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var args = null;
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// constructor function to be returned
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var __self = function()
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{
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if ( !( this instanceof __self ) )
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{
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// store arguments to be passed to constructor and
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// instantiate new object
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args = arguments;
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return new __self();
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}
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// generate and store unique instance id
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attachInstanceId( this, ++instance_id, __self );
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initInstance( instance_id, this );
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this.__initProps();
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// call the constructor, if one was provided
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if ( this.__construct instanceof Function )
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{
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// note that since 'this' refers to the new class (even
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// subtypes), and since we're using apply with 'this', the
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// constructor will be applied to subtypes without a problem
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this.__construct.apply( this, ( args || arguments ) );
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args = null;
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}
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// attach any instance properties/methods (done after
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// constructor to ensure they are not overridden)
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attachInstanceOf( this );
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// Provide a more intuitive string representation of the class
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// instance. If a toString() method was already supplied for us,
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// use that one instead.
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if ( !( Object.prototype.hasOwnProperty.call(
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members[ 'public' ], 'toString'
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) ) )
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{
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// use __toString if available (see enum_bug), otherwise use
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// our own defaults
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this.toString = members[ 'public' ].__toString
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|| ( ( cname )
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? function()
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{
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return '#<' + cname + '>';
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}
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: function()
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{
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return '#<anonymous>';
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}
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)
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;
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}
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};
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// provide a more intuitive string representation
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__self.toString = ( cname )
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? function() { return cname; }
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: function() { return '(Class)'; }
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;
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return __self;
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}
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/**
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* Creates the constructor for a new abstract class
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*
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* Calling this constructor will cause an exception to be thrown, as abstract
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* classes cannot be instantiated.
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*
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* @param {string} cname class name (may be empty)
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*
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* @return {function()} constructor
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*/
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function createAbstractCtor( cname )
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{
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var __abstract_self = function()
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{
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if ( !extending )
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{
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throw Error(
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"Abstract class " + ( cname || '(anonymous)' ) +
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" cannot be instantiated"
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);
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}
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};
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__abstract_self.toString = ( cname )
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? function()
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{
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return cname;
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}
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: function()
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{
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return '(AbstractClass)';
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}
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;
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return __abstract_self;
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}
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function buildMembers(
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