ES6-style constructors

Included with this change is a simple "wrapper" implementation:

```
// equivalent
easejs( Foo );
Class.extend( Foo, {} );
```

index.js

@@ -1,7 +1,7 @@
 /**
  * Provides ease of access to all submodules
  *
- *  Copyright (C) 2010, 2011, 2013, 2014 Free Software Foundation, Inc.
+ *  Copyright (C) 2010, 2011, 2013, 2014, 2015 Free Software Foundation, Inc.
  *
  *  This file is part of GNU ease.js.
  *
@@ -19,10 +19,26 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * Wrap a prototype using ease.js
+ *
+ * This function is the entry point for ease.js; its fields expose all of
+ * its core features.  When invoked, it wraps the given prototype using
+ * ease.js, producing an ease.js Class.  This is more natural when using the
+ * ECMAScript 6 `class` syntax to define prototypes.
+ *
+ * @param {Function} proto prototype to wrap
+ *
+ * @return {Function} ease.js Class wrapping PROTO
+ */
+var exports = module.exports = function( proto )
+{
+    return exports.Class.extend( proto, {} );
+};
+
 exports.Class         = require( './lib/class' );
 exports.AbstractClass = require( './lib/class_abstract' );
 exports.FinalClass    = require( './lib/class_final' );
 exports.Interface     = require( './lib/interface' );
 exports.Trait         = require( './lib/Trait' );
 exports.version       = require( './lib/version' );
-

lib/ClassBuilder.js

@@ -28,6 +28,8 @@ var util    = require( './util' ),
     Warning = require( './warn' ).Warning,
     Symbol  = require( './util/Symbol' ),
 
+    parseKeywords = require( './prop_parser' ).parseKeywords,
+
     hasOwn = Object.prototype.hasOwnProperty,
 
 
@@ -50,15 +52,27 @@ var util    = require( './util' ),
     /**
      * Hash of reserved members
      *
-     * These methods cannot be defined in the class. They are for internal use
+     * These methods cannot be defined in the class; they are for internal
-     * only. We must check both properties and methods to ensure that neither is
+     * use only. We must check both properties and methods to ensure that
-     * defined.
+     * neither is defined.
      *
      * @type {Object.<string,boolean>}
      */
     reserved_members = {
         '__initProps': true,
-        'constructor': true,
+    },
+
+    /**
+     * Hash of aliased members
+     *
+     * These are members that alias to another.  Ideally, this should be a
+     * very small list.  It is useful for introducing features without
+     * deprecating old.
+     *
+     * @type {Object.<string,string>}
+     */
+    aliased_members = {
+        'constructor': '__construct',
     },
 
     /**
@@ -641,12 +655,56 @@ exports.prototype.buildMembers = function buildMembers(
         parser.method   && hjoin( 'method', handlers.method );
     }
 
+    handlers.keywordParser = _keywordParser;
+
     // parse members and process accumulated member state
     util.propParse( props, handlers, context );
     this._memberBuilder.end( context.state );
 }
 
 
+/**
+ * Member keyword parser
+ *
+ * In reality, this parser is simply intended to override names where there
+ * are applicable aliases; all keyword parsing is kept to the original
+ * implementation.
+ *
+ * @param {string} prop property to parse
+ *
+ * @return  {{name: string, bitwords: number, keywords: Object.<string, boolean>}}
+ */
+function _keywordParser( prop )
+{
+    var result = parseKeywords( prop ),
+        alias  = _getMemberAlias( result.name );
+
+    if ( alias !== undefined )
+    {
+        result.name = alias;
+    }
+
+    return result;
+}
+
+
+/**
+ * Return a member alias for NAME
+ *
+ * If NAME has no alias, then the result is `undefined`.
+ *
+ * @param {string} name member name
+ *
+ * @return {string|undefined}
+ */
+function _getMemberAlias( name )
+{
+    return ( hasOwn.call( aliased_members, name ) )
+        ? aliased_members[ name ]
+        : undefined;
+}
+
+
 function _parseEach( name, value, keywords )
 {
     var defs = this.defs;

lib/prop_parser.js

@@ -1,7 +1,8 @@
 /**
  * Property keyword parser module
  *
- *  Copyright (C) 2010, 2011, 2012, 2013, 2014 Free Software Foundation, Inc.
+ *  Copyright (C) 2010, 2011, 2012, 2013, 2014, 2015
+ *  Free Software Foundation, Inc.
  *
  *  This file is part of GNU ease.js.
  *
@@ -60,7 +61,7 @@ exports.kmasks = _kmasks;
  *
  * @param  {string}  prop  property string, which may contain keywords
  *
- * @return  {{name: string, keywords: Object.<string, boolean>}}
+ * @return  {{name: string, bitwords: number, keywords: Object.<string, boolean>}}
  */
 exports.parseKeywords = function ( prop )
 {

test/Class/ConstructorTest.js

@@ -1,7 +1,7 @@
 /**
  * Tests class module constructor creation
  *
- *  Copyright (C) 2014 Free Software Foundation, Inc.
+ *  Copyright (C) 2014, 2015 Free Software Foundation, Inc.
  *
  *  This file is part of GNU ease.js.
  *
@@ -21,6 +21,24 @@
 
 require( 'common' ).testCase(
 {
+    caseSetUp: function()
+    {
+        // ease.js was written long before ES6 drafts began providing class
+        // support.  Now that they do, we should support their constructor
+        // decision as well as our own.
+        this.ctors = [ '__construct', 'constructor' ];
+
+        // we only use ES3 features, thus this
+        this.mkctor = function( name, f )
+        {
+            var o = {};
+            o[ name ] = f;
+
+            return o;
+        };
+    },
+
+
     setUp: function()
     {
         this.Sut = this.require( 'class' );
@@ -32,10 +50,15 @@ require( 'common' ).testCase(
      * defining the class. (Note that the case of ensuring that it is not
      * called when creating a subtype is handled by the ExtendTest case.)
      */
-    'Constructor should not be invoked before instantiation': function()
+    '@each(ctors) Should not be invoked before instantiation':
+    function( name )
     {
-        var called = false;
+        var called = false,
-        this.Sut.extend( { __construct: function() { called = true; } } );
+            dfn    = {};
+
+        this.Sut.extend(
+            this.mkctor( name, function() { called = true; } )
+        );
 
         this.assertNotEqual( called, true );
     },
@@ -47,14 +70,14 @@ require( 'common' ).testCase(
      * is instantiated. Further, it should only be called a single time,
      * which is particularly important if it produces side-effects.
      */
-    'Constructor should be invoked once upon instantiation': function()
+    '@each(ctors) Should be invoked once upon instantiation':
+    function( name )
     {
         var called = 0;
 
         var Foo = this.Sut.extend(
-        {
+            this.mkctor( name, function() { called++; } )
-            __construct: function() { called++; }
+        );
-        } );
 
         // note that we're not yet testing the more consise new-less
         // invocation style
@@ -67,17 +90,20 @@ require( 'common' ).testCase(
      * Once invoked, the __construct method should be bound to the newly
      * created instance.
      */
-    'Constructor should be invoked within context of new instance':
+    '@each(ctors) Should be invoked within context of new instance':
-    function()
+    function( name )
     {
         var expected = Math.random();
 
-        var Foo = this.Sut.extend(
+        var dfn = this.mkctor( name, function()
         {
-                val: null,
+            this.val = expected;
-                __construct: function() { this.val = expected; }
         } );
 
+        dfn.val = null;
+
+        var Foo = this.Sut.extend( dfn );
+
         // if `this' was bound to the instance, then __construct should set
         // VAL to EXPECTED
         var inst = new Foo();
@@ -90,19 +116,18 @@ require( 'common' ).testCase(
      * ``class'') should be passed to __construct, unchanged and
      * uncopied---that is, references should be retained.
      */
-    'Constructor arguments should be passed unchanged to __construct':
+    '@each(ctors) Arguments should be passed unchanged to __construct':
-    function()
+    function( name )
     {
         var args  = [ "foo", { bar: 'baz' }, [ 'moo', 'cow' ] ],
             given = null;
 
         var Foo = this.Sut.extend(
-        {
+            this.mkctor( name, function()
-            __construct: function()
             {
                 given = Array.prototype.slice.call( arguments, 0 );
-            }
+            } )
-        } );
+        );
 
         new Foo( args[ 0 ], args[ 1 ], args[ 2 ] );
 
@@ -125,15 +150,16 @@ require( 'common' ).testCase(
      * the name __construct---is modelled after PHP; Java classes, for
      * instance, do not inherit their parents' constructors.
      */
-    'Parent constructor should be invoked for subtype if not overridden':
+    '@each(ctors)Parent constructor invoked for subtype if not overridden':
-    function()
+    function( name )
     {
         var called = false;
 
-        var Sub = this.Sut.extend(
+        var dfn = {};
-        {
+        dfn[ name ] = function() { called = true; };
-            __construct: function() { called = true; }
+
-        } ).extend( {} );
+        var Sub = this.Sut.extend( dfn )
+            .extend( {} );
 
         new Sub();
         this.assertOk( called );
@@ -172,18 +198,22 @@ require( 'common' ).testCase(
      * __construct, since public is the default and there is no other
      * option.)
      */
-    '__construct must be public': function()
+    '@each(ctors) Constructor must be public': function( name )
     {
         var Sut = this.Sut;
 
         this.assertThrows( function()
         {
-            Sut( { 'protected __construct': function() {} } );
+            var dfn = {};
+            dfn[ 'protected ' + name ] = function() {};
+            Sut( dfn );
         }, TypeError, "Constructor should not be able to be protected" );
 
         this.assertThrows( function()
         {
-            Sut( { 'private __construct': function() {} } );
+            var dfn = {};
+            dfn[ 'private ' + name ] = function() {};
+            Sut( dfn );
         }, TypeError, "Constructor should not be able to be private" );
     },
 
@@ -200,4 +230,35 @@ require( 'common' ).testCase(
         var Foo = this.Sut.extend( {} );
         this.assertStrictEqual( Foo().constructor, Foo );
     },
+
+
+    /**
+     * We support multiple constructor styles; only one may be provided.
+     *
+     * This error should happen as a consequence of other method checks that
+     * prohibit redefinitions.
+     */
+    'Cannot provide multiple constructor styles': function()
+    {
+        var Sut = this.Sut,
+            len = this.ctors.length;
+
+        // this will not test every permutation, but will hopefully be a
+        // reasonable test in the event that any additional constructors are
+        // added in the future (we start at 1 because it'll wrap modulo LEN)
+        for ( var i = 1; i < len; i++ )
+        {
+            var dfn = {},
+                a   = this.ctors[ i ],
+                b   = this.ctors[ ( i + 1 ) % len ];
+
+            dfn[ a ] = function() {};
+            dfn[ b ] = function() {};
+
+            this.assertThrows( function()
+            {
+                Sut( dfn );
+            }, Error, "Multiple constructors should not be permitted" );
+        }
+    },
 } );

test/ClassBuilder/MemberRestrictionTest.js

@@ -1,7 +1,7 @@
 /**
  * Tests class builder member restrictions
  *
- *  Copyright (C) 2014 Free Software Foundation, Inc.
+ *  Copyright (C) 2014, 2015 Free Software Foundation, Inc.
  *
  *  This file is part of GNU ease.js.
  *
@@ -88,7 +88,7 @@ require( 'common' ).testCase(
      */
     'Proper members are reserved': function()
     {
-        var chk      = [ '__initProps', 'constructor' ],
+        var chk      = [ '__initProps' ],
             i        = chk.length,
             reserved = this.Sut.getReservedMembers();
 

test/IndexTest.js

@@ -1,7 +1,7 @@
 /**
  * Tests index.js
  *
- *  Copyright (C) 2014 Free Software Foundation, Inc.
+ *  Copyright (C) 2014, 2015 Free Software Foundation, Inc.
  *
  *  This file is part of GNU ease.js.
  *
@@ -63,4 +63,27 @@ require( 'common' ).testCase(
     {
         this.exportedAs( 'version', 'version' );
     },
+
+
+    /**
+     * Since ECMAScript 6 introduces the ability to define prototypes using
+     * the `class` keyword and some syntatic sugar, it is awkward to use the
+     * traditional ease.js class abstraction with it.  Instead, if a user
+     * wishes to wrap a prototype defined in this manner (to take advantage
+     * of ease.js' features), it would be more appropriate to make it look
+     * like we're doing just that.
+     *
+     * This is a shorthand for Class.extend( proto, {} ).
+     */
+    'Invoking is equivalent to extending with empty definition': function()
+    {
+        var proto  = function() {},
+            result = this.Sut( proto );
+
+        this.assertOk( this.Sut.Class.isClass( result ) );
+
+        // this is not a comprehensive test (once we add reflection of some
+        // sort, verify that nothing is added to the prototype)
+        this.assertOk( this.Sut.Class.isA( proto, result() ) );
+    },
 } );