gistfile1.js

YUI.add('root-cls', function (Y) {
    Y.Base._buildCfg.aggregates.push('getClassAttrs');
    
    Y.rootClass = Y.Base.create('root-class', Y.Base, [], {
        someInstanceMethod :  function () {}
    }, {
        ATTRS : {
            test : {
                validator : Y.Lang.isBoolean
            }
        }
    });
    
    Y.rootExt = Y.Base.create('root-ext', Y.Base, [], {}, {        
        getClassAttrs : function () {
            var attrs = {},
                c = this.prototype.constructor;
            
            while (c) {
                Y.mix(attrs, c.ATTRS, true);
                c = (c.superclass ? c.superclass.constructor : null);
            }
            
            return attrs;
        }
    });
    
}, '1.0', {requires : ['base']});

YUI().use('root-cls', function (Y) {
    var mainClass = Y.Base.create('main-class', Y.rootClass, [Y.rootExt], {}, {
        ATTRS : {
            foo : {
                validator : Y.Lang.isNumber
            },
            bar : {
                validator : Y.Lang.isString
            }
        }
    });

    console.log('class method: ', mainClass.getClassAttrs)
    console.log('class instanceof: ', new mainClass() instanceof Y.rootClass);
    console.log('class attrs: ', mainClass.getClassAttrs());
    
    var mySubClass = Y.Base.create('my-subclass', mainClass, [Y.rootExt], {}, {
        ATTRS : {
            baz : {
                validator : Y.Lang.isBoolean,
                value : false
            }
        }
    });
    
    console.log('subclass method: ', mySubClass.getClassAttrs)
    console.log('subclass instanceof: ', new mySubClass() instanceof Y.rootClass);
    console.log('subclass attrs: ', mySubClass.getClassAttrs());    
});