diff --git a/lib/FallbackVisibilityObjectFactory.js b/lib/FallbackVisibilityObjectFactory.js
new file mode 100644
index 0000000..84d5f98
--- /dev/null
+++ b/lib/FallbackVisibilityObjectFactory.js
@@ -0,0 +1,24 @@
+/**
+ * Contains fallback visibility object factory
+ *
+ * Copyright (C) 2010 Mike Gerwitz
+ *
+ * This file is part of ease.js.
+ *
+ * ease.js is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see .
+ *
+ * @author Mike Gerwitz
+ * @package core
+ */
+
diff --git a/lib/VisibilityObjectFactory.js b/lib/VisibilityObjectFactory.js
new file mode 100644
index 0000000..963a678
--- /dev/null
+++ b/lib/VisibilityObjectFactory.js
@@ -0,0 +1,236 @@
+/**
+ * Contains visibility object factory
+ *
+ * Copyright (C) 2010 Mike Gerwitz
+ *
+ * This file is part of ease.js.
+ *
+ * ease.js is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see .
+ *
+ * @author Mike Gerwitz
+ * @package core
+ */
+
+/**
+ * XXX: tightly coupled
+ */
+var util = require( __dirname + '/util' );
+
+
+/**
+ * Initializes visibility object factory
+ *
+ * The visibility object is the "magic" behind ease.js. This factory creates the
+ * object that holds the varying levels of visibility, which are swapped out and
+ * inherited depending on circumstance.
+ */
+module.exports = exports = function VisibilityObjectFactory()
+{
+ // permit omitting 'new' keyword
+ if ( !( this instanceof exports ) )
+ {
+ return new exports();
+ }
+};
+
+
+/**
+ * Sets up properties
+ *
+ * This includes all members (including private). Private members will be set up
+ * in a separate object, so that they can be easily removed from the mix. That
+ * object will include the destination object in the prototype, so that the
+ * access should be transparent. This object is returned.
+ *
+ * @param {Object} dest destination object
+ * @param {Object} properties properties to copy
+ * @param {Object=} methods methods to copy
+ *
+ * @return {Object} object containing private members and dest as prototype
+ */
+exports.prototype.setup = function setup( dest, properties, methods )
+{
+ // create the private layer atop of the destination object
+ var obj = this._createPrivateLayer( dest, properties );
+
+ // initialize each of the properties for this instance to
+ // ensure we're not sharing references to prototype values
+ this._doSetup( dest, properties[ 'public' ] );
+
+ // Do the same for protected, but only if they do not exist already in
+ // public. The reason for this is because the property object is laid /atop/
+ // of the public members, meaning that a parent's protected members will
+ // take precedence over a subtype's overriding /public/ members. Uh oh.
+ this._doSetup( dest,
+ properties[ 'protected' ],
+ methods[ 'protected' ],
+ 'public'
+ );
+
+ // then add the private parts
+ this._doSetup( obj, properties[ 'private' ], methods[ 'private' ] );
+
+ return obj;
+};
+
+
+/**
+ * Add an extra layer atop the destination object, which will contain the
+ * private members
+ *
+ * The object provided will be used as the prototype for the new private layer,
+ * so the provided object will be accessible on the prototype chain.
+ *
+ * Subtypes may override this method to alter the functionality of the private
+ * visibility object (e.g. to prevent it from being created).
+ *
+ * @param {Object} atop_of object to add private layer atop of
+ *
+ * @return {Object} private layer with given object as prototype
+ */
+exports.prototype._createPrivateLayer = function( atop_of, properties )
+{
+ var obj_ctor = function() {};
+ obj_ctor.prototype = atop_of;
+
+ // we'll be returning an instance, so that the prototype takes effect
+ obj = new obj_ctor();
+
+ // All protected properties need to be proxied from the private object
+ // (which will be passed as the context) to the object containing protected
+ // values. Otherwise, the protected property values would be set on the
+ // private object, making them inaccessible to subtypes.
+ this.createPropProxy( atop_of, obj, properties[ 'protected' ] );
+
+ return obj;
+};
+
+
+/**
+ * Set up destination object by copying over properties and methods
+ *
+ * @param {Object} dest destination object
+ * @param {Object} properties properties to copy
+ * @param {Object=} methods methods to copy
+ * @param {boolean} unless_keyword do not set if keyword is set on existing
+ * method
+ *
+ * @return {undefined}
+ */
+exports.prototype._doSetup = function(
+ dest, properties, methods, unless_keyword
+)
+{
+ var hasOwn = Array.prototype.hasOwnProperty,
+ pre = null;
+
+ // copy over the methods
+ if ( methods !== undefined )
+ {
+ for ( method_name in methods )
+ {
+ if ( hasOwn.call( methods, method_name ) )
+ {
+ pre = dest[ method_name ];
+
+ // If requested, do not copy the method over if it already
+ // exists in the destination object. Don't use hasOwn here;
+ // unnecessary overhead and we want to traverse any prototype
+ // chains. We do not check the public object directly, for
+ // example, because we need a solution that will work if a proxy
+ // is unsupported by the engine.
+ //
+ // Also note that we need to allow overriding if it exists in
+ // the protected object (we can override protected with
+ // protected). This is the *last* check to ensure a performance
+ // hit is incured *only* if we're overriding protected with
+ // protected.
+ if ( !unless_keyword
+ || ( pre === undefined )
+ || !( pre.___$$keywords$$[ unless_keyword ] )
+ )
+ {
+ dest[ method_name ] = methods[ method_name ];
+ }
+ }
+ }
+ }
+
+ // initialize private/protected properties and store in instance data
+ for ( prop in properties )
+ {
+ if ( hasOwn.call( properties, prop ) )
+ {
+ dest[ prop ] = util.clone( properties[ prop ][ 0 ] );
+ }
+ }
+}
+
+
+/**
+ * Creates a proxy for all given properties to the given base
+ *
+ * The proxy uses getters/setters to forward all calls to the base. The
+ * destination object will be used as the proxy. All properties within props
+ * will be used proxied.
+ *
+ * To summarize: for each property in props, all gets and sets will be forwarded
+ * to base.
+ *
+ * Please note that this does not use the JS proxy implementation. That will be
+ * done in the future for engines that support it.
+ *
+ * @param {Object} base object to proxy to
+ * @param {Object} dest object to treat as proxy (set getters/setters on)
+ * @param {Object} props properties to proxy
+ *
+ * @return {Object} returns dest
+ */
+exports.prototype.createPropProxy = function( base, dest, props )
+{
+ var hasOwn = Object.prototype.hasOwnProperty;
+
+ for ( prop in props )
+ {
+ if ( !( hasOwn.call( props, prop ) ) )
+ {
+ continue;
+ }
+
+ ( function( prop )
+ {
+ // just in case it's already defined, so we don't throw an error
+ dest[ prop ] = undefined;
+
+ // public properties, when set internally, must forward to the
+ // actual variable
+ Object.defineProperty( dest, prop, {
+ set: function( val )
+ {
+ base[ prop ] = val;
+ },
+
+ get: function()
+ {
+ return base[ prop ];
+ },
+
+ enumerable: true,
+ } );
+ } ).call( null, prop );
+ }
+
+ return dest;
+};
+
diff --git a/lib/propobj.js b/lib/propobj.js
index d4f7f04..0585ca1 100644
--- a/lib/propobj.js
+++ b/lib/propobj.js
@@ -38,6 +38,10 @@ var util = require( __dirname + '/util' ),
* object will include the destination object in the prototype, so that the
* access should be transparent. This object is returned.
*
+ * Properties are expected in the following format. Note that keywords are
+ * ignored:
+ * { public: { prop: [ value, { keyword: true } ] } }
+ *
* @param {Object} dest destination object
* @param {Object} properties properties to copy
* @param {Object=} methods methods to copy
diff --git a/test/test-VisibilityObjectFactory.js b/test/test-VisibilityObjectFactory.js
new file mode 100644
index 0000000..504b747
--- /dev/null
+++ b/test/test-VisibilityObjectFactory.js
@@ -0,0 +1,291 @@
+/**
+ * Tests visibility object factory
+ *
+ * Copyright (C) 2010 Mike Gerwitz
+ *
+ * This file is part of ease.js.
+ *
+ * ease.js is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see .
+ *
+ * @author Mike Gerwitz
+ * @package test
+ */
+
+
+var common = require( './common' ),
+ assert = require( 'assert' );
+
+// we cannot perform these tests if it's not supported by our environment
+if ( common.require( 'util' ).definePropertyFallback() )
+{
+ return;
+}
+
+ // SUT
+var VisibilityObjectFactory = common.require( 'VisibilityObjectFactory' ),
+
+ sut = VisibilityObjectFactory(),
+
+ // properties are expected to be in a specific format
+ props = {
+ 'public': {
+ pub: [ [ 'foo' ], {} ],
+ },
+ 'protected': {
+ prot: [ [ 'bar' ], {} ],
+ },
+ 'private': {
+ priv: [ [ 'baz' ], {} ],
+ },
+ },
+
+ methods = {
+ 'public': {
+ fpub: ( function()
+ {
+ var retval = function() {};
+ retval.___$$keywords$$ = { 'public': true };
+
+ return retval;
+ } )(),
+ },
+ 'protected': {
+ fprot: function() {},
+ },
+ 'private': {
+ fpriv: function() {},
+ },
+ }
+;
+
+
+/**
+ * To keep with the spirit of ease.js, we should be able to instantiate
+ * VisibilityObjectFactory both with and without the 'new' keyword
+ *
+ * Consistency is key with these sorts of things.
+ */
+( function testCanInstantiateWithAndWithoutNewKeyword()
+{
+ // with 'new' keyword
+ assert.ok(
+ ( new VisibilityObjectFactory() ) instanceof VisibilityObjectFactory,
+ "Should be able to instantiate VisibilityObjectFactory with 'new' " +
+ "keyword"
+ );
+
+ // without 'new' keyword
+ assert.ok( VisibilityObjectFactory() instanceof VisibilityObjectFactory,
+ "Should be able to instantiate VisibilityObjectFactory without 'new' " +
+ "keyword"
+ );
+} )();
+
+
+/**
+ * One of the core requirements for proper visibility support is the ability to
+ * create a proxy object. Proxy objects transfer gets/sets of a certain property
+ * to another object. This allows objects to be layered atop each other while
+ * still permitting gets/sets to fall through.
+ */
+( function testCanCreatePropertyProxy()
+{
+ var base = {},
+ dest = {},
+ props = { one: true, two: true, three: true },
+ val = 'foo',
+ val2 = 'bar'
+ ;
+
+ // create proxy of props to base on dest
+ sut.createPropProxy( base, dest, props );
+
+ // check to ensure the properties are properly proxied
+ for ( prop in props )
+ {
+ dest[ prop ] = val;
+
+ // check proxy
+ assert.equal( dest[ prop ], val,
+ "Property can be set/retrieved on destination object"
+ );
+
+ // check base
+ assert.equal( base[ prop ], val,
+ "Property can be set via proxy and retrieved on base"
+ );
+
+ // set to new value
+ base[ prop ] = val2;
+
+ // re-check proxy
+ assert.equal( dest[ prop ], val2,
+ "Property can be set on base and retrieved on dest object"
+ );
+ }
+} )();
+
+
+/**
+ * An additional layer should be created, which will hold the private members.
+ */
+( function testSetupCreatesPrivateLayer()
+{
+ var dest = { foo: [] },
+ obj = sut.setup( dest, props, methods );
+
+ assert.notEqual( obj, dest,
+ "Returned object should not be the destination object"
+ );
+
+ assert.strictEqual( obj.foo, dest.foo,
+ "Destination object is part of the prototype chain of the returned obj"
+ );
+} )();
+
+
+/**
+ * All protected properties must be proxied from the private layer to the
+ * protected. Otherwise, sets would occur on the private object, which would
+ * prevent them from being accessed by subtypes if set by a parent method
+ * invocation. (The same is true in reverse.)
+ */
+( function testPrivateLayerIncludesProtectedMemberProxy()
+{
+ var dest = {},
+ obj = sut.setup( dest, props, methods ),
+ val = 'foo'
+ ;
+
+ obj.prot = val;
+ assert.equal( dest.prot, val,
+ "Protected values are proxied from private layer"
+ );
+} )();
+
+
+/**
+ * Public properties should be initialized on the destination object to ensure
+ * that references are not shared between instances (that'd be a pretty nasty
+ * bug).
+ *
+ * Note that we do not care about public methods, because they're assumed to
+ * already be part of the prototype chain. The visibility object is only
+ * intended to handle levels of visibility that are not directly implemented in
+ * JS. Public methods are a direct consequence of adding a property to the
+ * prototype chain.
+ */
+( function testPublicPropertiesAreCopiedToDestinationObject()
+{
+ var dest = {};
+ sut.setup( dest, props, methods );
+
+ // values should match
+ assert.equal( dest.pub[ 0 ], props[ 'public' ].pub[ 0 ],
+ "Public properties are properly initialized"
+ );
+
+ // ensure references are not shared (should be cloned)
+ assert.notStrictEqual( dest.pub, props[ 'public' ].pub,
+ "Public properties should not be copied by reference"
+ );
+
+ // method references should NOT be transferred (they're assumed to already
+ // be a part of the prototype chain, since they're outside the scope of the
+ // visibility object)
+ assert.equal( dest.fpub, undefined,
+ "Public method references should not be copied"
+ );
+} )();
+
+
+/**
+ * Protected properties should be copied over for the same reason that public
+ * properties should, in addition to the fact that the protected members are not
+ * likely to be present on the destination object. In addition, methods will be
+ * copied over.
+ */
+( function testProtectedPropertiesAndMethodsAreAddedToDestinationObject()
+{
+ var dest = {};
+ sut.setup( dest, props, methods );
+
+ // values should match
+ assert.equal( dest.prot[ 0 ], props[ 'protected' ].prot[ 0 ],
+ "Protected properties are properly initialized"
+ );
+
+ // ensure references are not shared (should be cloned)
+ assert.notStrictEqual( dest.prot, props[ 'protected' ].prot,
+ "Protected properties should not be copied by reference"
+ );
+
+ // protected method references should be copied
+ assert.strictEqual( dest.fprot, methods[ 'protected' ].fprot,
+ "Protected members should be copied by reference"
+ );
+} )();
+
+
+/**
+ * Public members should *always* take precedence over protected. The reason for
+ * this is because, if a protected member is overridden and made public by a
+ * subtype, we need to ensure that the protected member of the supertype doesn't
+ * take precedence. The reason it would take precedence by default is because
+ * the protected visibility object is laid *atop* the public, meaning it comes
+ * first in the prototype chain.
+ */
+( function testPublicMethodsAreNotOverwrittenByProtected()
+{
+ // use the public method
+ var dest = { fpub: methods[ 'public' ].fpub };
+
+ // add duplicate method to protected
+ methods[ 'protected' ].fpub = function() {};
+
+ sut.setup( dest, props, methods );
+
+ // ensure our public method is still referenced
+ assert.strictEqual( dest.fpub, methods[ 'public' ].fpub,
+ "Public methods should not be overwritten by protected methods"
+ );
+} )();
+
+
+/**
+ * Same situation with private members as protected, with the exception that we
+ * do not need to worry about the overlay problem (in regards to methods). This
+ * is simply because private members are not inherited.
+ */
+( function testPrivatePropertiesAndMethodsAreAddedToDestinationObject()
+{
+ var dest = {},
+ obj = sut.setup( dest, props, methods );
+
+ // values should match
+ assert.equal( obj.priv[ 0 ], props[ 'private' ].priv[ 0 ],
+ "Private properties are properly initialized"
+ );
+
+ // ensure references are not shared (should be cloned)
+ assert.notStrictEqual( obj.priv, props[ 'private' ].priv,
+ "Private properties should not be copied by reference"
+ );
+
+ // private method references should be copied
+ assert.strictEqual( obj.fpriv, methods[ 'private' ].fpriv,
+ "Private members should be copied by reference"
+ );
+} )();
+
diff --git a/tools/combine b/tools/combine
index d624bfc..9f4c9d6 100755
--- a/tools/combine
+++ b/tools/combine
@@ -29,7 +29,8 @@ TPL_VAR='/**{CONTENT}**/'
RMTRAIL="$PATH_TOOLS/rmtrail"
# order matters
-CAT_MODULES="warn prop_parser util propobj member_builder ClassBuilder"
+CAT_MODULES="warn prop_parser util propobj VisibilityObjectFactory"
+CAT_MODULES="$CAT_MODULES member_builder ClassBuilder"
CAT_MODULES="$CAT_MODULES class class_final class_abstract interface"
##