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                                /**
                                 * The base module provides the Base class, which objects requiring attribute and custom event support can extend.
                                 * The module also provides two ways to reuse code - It augments Base with the Plugin.Host interface which provides
                                 * plugin support and also provides the BaseCore.build method which provides a way to build custom classes using extensions.
                                 *
                                 * @module base
                                 */

                                /**
                                 * <p>The base-core module provides the BaseCore class, the lightest version of Base,
                                 * which provides Base's basic lifecycle management and ATTRS construction support,
                                 * but doesn't fire init/destroy or attribute change events.</p>
                                 *
                                 * <p>It mixes in AttributeCore, which is the lightest version of Attribute</p>
                                 *
                                 * @module base
                                 * @submodule base-core
                                 */
                                var O = Y.Object,
                                    L = Y.Lang,
                                    DOT = ".",
                                    INITIALIZED = "initialized",
                                    DESTROYED = "destroyed",
                                    INITIALIZER = "initializer",
                                    VALUE = "value",
                                    OBJECT_CONSTRUCTOR = Object.prototype.constructor,
                                    DEEP = "deep",
                                    SHALLOW = "shallow",
                                    DESTRUCTOR = "destructor",

                                    AttributeCore = Y.AttributeCore,

                                    _wlmix = function(r, s, wlhash) {
                                        var p;
                                        for (p in s) {
                                            if(wlhash[p]) {
                                                r[p] = s[p];
                                            }
                                        }
                                        return r;
                                    };

                                /**
                                 * The BaseCore class, is the lightest version of Base, and provides Base's
                                 * basic lifecycle management and ATTRS construction support, but doesn't
                                 * fire init/destroy or attribute change events.
                                 *
                                 * BaseCore also handles the chaining of initializer and destructor methods across
                                 * the hierarchy as part of object construction and destruction. Additionally, attributes
                                 * configured through the static <a href="#property_BaseCore.ATTRS">ATTRS</a>
                                 * property for each class in the hierarchy will be initialized by BaseCore.
                                 *
                                 * Classes which require attribute support, but don't intend to use/expose attribute
                                 * change events can extend BaseCore instead of Base for optimal kweight and
                                 * runtime performance.
                                 *
                                 * **3.11.0 BACK COMPAT NOTE FOR COMPONENT DEVELOPERS**
                                 *
                                 * Prior to version 3.11.0, ATTRS would get added a class at a time. That is:
                                 *
                                 * <pre>
                                 *    for each (class in the hierarchy) {
                                 *       Call the class Extension constructors.
                                 *
                                 *       Add the class ATTRS.
                                 *
                                 *       Call the class initializer
                                 *       Call the class Extension initializers.
                                 *    }
                                 * </pre>
                                 *
                                 * As of 3.11.0, ATTRS from all classes in the hierarchy are added in one `addAttrs` call
                                 * before **any** initializers are called. That is, the flow becomes:
                                 *
                                 * <pre>
                                 *    for each (class in the hierarchy) {
                                 *       Call the class Extension constructors.
                                 *    }
                                 *
                                 *    Add ATTRS for all classes
                                 *
                                 *    for each (class in the hierarchy) {
                                 *       Call the class initializer.
                                 *       Call the class Extension initializers.
                                 *    }
                                 * </pre>
                                 *
                                 * Adding all ATTRS at once fixes subtle edge-case issues with subclass ATTRS overriding
                                 * superclass `setter`, `getter` or `valueFn` definitions and being unable to get/set attributes
                                 * defined by the subclass. It also leaves us with a cleaner order of operation flow moving
                                 * forward.
                                 *
                                 * However, it may require component developers to upgrade their components, for the following
                                 * scenarios:
                                 *
                                 * 1. It impacts components which may have `setter`, `getter` or `valueFn` code which
                                 * expects a superclass' initializer to have run.
                                 *
                                 * This is expected to be rare, but to support it, Base now supports a `_preAddAttrs()`, method
                                 * hook (same signature as `addAttrs`). Components can implement this method on their prototype
                                 * for edge cases which do require finer control over the order in which attributes are added
                                 * (see widget-htmlparser for example).
                                 *
                                 * 2. Extension developers may need to move code from Extension constructors to `initializer`s
                                 *
                                 * Older extensions, which were written before `initializer` support was added, had a lot of
                                 * initialization code in their constructors. For example, code which acccessed superclass
                                 * attributes. With the new flow this code would not be able to see attributes. The recommendation
                                 * is to move this initialization code to an `initializer` on the Extension, which was the
                                 * recommendation for anything created after `initializer` support for Extensions was added.
                                 *
                                 * @class BaseCore
                                 * @constructor
                                 * @uses AttributeCore
                                 * @param {Object} cfg Object with configuration property name/value pairs.
                                 * The object can be used to provide initial values for the objects published
                                 * attributes.
                                 */
                                function BaseCore(cfg) {
                                    if (!this._BaseInvoked) {
                                        this._BaseInvoked = true;

                                        Y.log('constructor called', 'life', 'base');
                                        this._initBase(cfg);
                                    }
                                    else { Y.log('Based constructor called more than once. Ignoring duplicate calls', 'life', 'base'); }
                                }

                                /**
                                 * The list of properties which can be configured for each attribute
                                 * (e.g. setter, getter, writeOnce, readOnly etc.)
                                 *
                                 * @property _ATTR_CFG
                                 * @type Array
                                 * @static
                                 * @private
                                 */
                                BaseCore._ATTR_CFG = AttributeCore._ATTR_CFG.concat("cloneDefaultValue");

                                /**
                                 * The array of non-attribute configuration properties supported by this class.
                                 *
                                 * For example `BaseCore` defines a "plugins" configuration property which
                                 * should not be set up as an attribute. This property is primarily required so
                                 * that when <a href="#property__allowAdHocAttrs">`_allowAdHocAttrs`</a> is enabled by a class,
                                 * non-attribute configuration properties don't get added as ad-hoc attributes.
                                 *
                                 * @property _NON_ATTRS_CFG
                                 * @type Array
                                 * @static
                                 * @private
                                 */
                                BaseCore._NON_ATTRS_CFG = ["plugins"];

                                /**
                                 * This property controls whether or not instances of this class should
                                 * allow users to add ad-hoc attributes through the constructor configuration
                                 * hash.
                                 *
                                 * AdHoc attributes are attributes which are not defined by the class, and are
                                 * not handled by the MyClass._NON_ATTRS_CFG
                                 *
                                 * @property _allowAdHocAttrs
                                 * @type boolean
                                 * @default undefined (false)
                                 * @protected
                                 */

                                /**
                                 * The string to be used to identify instances of this class.
                                 *
                                 * Classes extending BaseCore, should define their own
                                 * static NAME property, which should be camelCase by
                                 * convention (e.g. MyClass.NAME = "myClass";).
                                 *
                                 * @property NAME
                                 * @type String
                                 * @static
                                 */
                                BaseCore.NAME = "baseCore";

                                /**
                                 * The default set of attributes which will be available for instances of this class, and
                                 * their configuration. In addition to the configuration properties listed by
                                 * AttributeCore's <a href="AttributeCore.html#method_addAttr">addAttr</a> method,
                                 * the attribute can also be configured with a "cloneDefaultValue" property, which
                                 * defines how the statically defined value field should be protected
                                 * ("shallow", "deep" and false are supported values).
                                 *
                                 * By default if the value is an object literal or an array it will be "shallow"
                                 * cloned, to protect the default value.
                                 *
                                 * @property ATTRS
                                 * @type Object
                                 * @static
                                 */
                                BaseCore.ATTRS = {
                                    /**
                                     * Flag indicating whether or not this object
                                     * has been through the init lifecycle phase.
                                     *
                                     * @attribute initialized
                                     * @readonly
                                     * @default false
                                     * @type boolean
                                     */
                                    initialized: {
                                        readOnly:true,
                                        value:false
                                    },

                                    /**
                                     * Flag indicating whether or not this object
                                     * has been through the destroy lifecycle phase.
                                     *
                                     * @attribute destroyed
                                     * @readonly
                                     * @default false
                                     * @type boolean
                                     */
                                    destroyed: {
                                        readOnly:true,
                                        value:false
                                    }
                                };

                                /**
                                Provides a way to safely modify a `Y.BaseCore` subclass' static `ATTRS`
                                after the class has been defined or created.

                                BaseCore-based classes cache information about the class hierarchy in order
                                to efficiently create instances. This cache includes includes the aggregated
                                `ATTRS` configs. If the static `ATTRS` configs need to be modified after the
                                class has been defined or create, then use this method which will make sure
                                to clear any cached data before making any modifications.

                                @method modifyAttrs
                                @param {Function} [ctor] The constructor function whose `ATTRS` should be
                                    modified. If a `ctor` function is not specified, then `this` is assumed
                                    to be the constructor which hosts the `ATTRS`.
                                @param {Object} configs The collection of `ATTRS` configs to mix with the
                                    existing attribute configurations.
                                @static
                                @since 3.10.0
                                **/
                                BaseCore.modifyAttrs = function (ctor, configs) {
                                    // When called without a constructor, assume `this` is the constructor.
                                    if (typeof ctor !== 'function') {
                                        configs = ctor;
                                        ctor    = this;
                                    }

                                    var attrs, attr, name;

                                    // Eagerly create the `ATTRS` object if it doesn't already exist.
                                    attrs = ctor.ATTRS || (ctor.ATTRS = {});

                                    if (configs) {
                                        // Clear cache because it has ATTRS aggregation data which is about
                                        // to be modified.
                                        ctor._CACHED_CLASS_DATA = null;

                                        for (name in configs) {
                                            if (configs.hasOwnProperty(name)) {
                                                attr = attrs[name] || (attrs[name] = {});
                                                Y.mix(attr, configs[name], true);
                                            }
                                        }
                                    }
                                };

                                BaseCore.prototype = {

                                    /**
                                     * Internal construction logic for BaseCore.
                                     *
                                     * @method _initBase
                                     * @param {Object} config The constructor configuration object
                                     * @private
                                     */
                                    _initBase : function(config) {
                                        Y.log('init called', 'life', 'base');

                                        Y.stamp(this);

                                        this._initAttribute(config);

                                        // If Plugin.Host has been augmented [ through base-pluginhost ], setup it's
                                        // initial state, but don't initialize Plugins yet. That's done after initialization.
                                        var PluginHost = Y.Plugin && Y.Plugin.Host;
                                        if (this._initPlugins && PluginHost) {
                                            PluginHost.call(this);
                                        }

                                        if (this._lazyAddAttrs !== false) { this._lazyAddAttrs = true; }

                                        /**
                                         * The string used to identify the class of this object.
                                         *
                                         * @deprecated Use this.constructor.NAME
                                         * @property name
                                         * @type String
                                         */
                                        this.name = this.constructor.NAME;

                                        this.init.apply(this, arguments);
                                    },

                                    /**
                                     * Initializes AttributeCore
                                     *
                                     * @method _initAttribute
                                     * @private
                                     */
                                    _initAttribute: function() {
                                        AttributeCore.call(this);
                                    },

                                    /**
                                     * Init lifecycle method, invoked during construction. Sets up attributes
                                     * and invokes initializers for the class hierarchy.
                                     *
                                     * @method init
                                     * @chainable
                                     * @param {Object} cfg Object with configuration property name/value pairs
                                     * @return {BaseCore} A reference to this object
                                     */
                                    init: function(cfg) {
                                        Y.log('init called', 'life', 'base');

                                        this._baseInit(cfg);

                                        return this;
                                    },

                                    /**
                                     * Internal initialization implementation for BaseCore
                                     *
                                     * @method _baseInit
                                     * @private
                                     */
                                    _baseInit: function(cfg) {
                                        this._initHierarchy(cfg);

                                        if (this._initPlugins) {
                                            // Need to initPlugins manually, to handle constructor parsing, static Plug parsing
                                            this._initPlugins(cfg);
                                        }
                                        this._set(INITIALIZED, true);
                                    },

                                    /**
                                     * Destroy lifecycle method. Invokes destructors for the class hierarchy.
                                     *
                                     * @method destroy
                                     * @return {BaseCore} A reference to this object
                                     * @chainable
                                     */
                                    destroy: function() {
                                        this._baseDestroy();
                                        return this;
                                    },

                                    /**
                                     * Internal destroy implementation for BaseCore
                                     *
                                     * @method _baseDestroy
                                     * @private
                                     */
                                    _baseDestroy : function() {
                                        if (this._destroyPlugins) {
                                            this._destroyPlugins();
                                        }
                                        this._destroyHierarchy();
                                        this._set(DESTROYED, true);
                                    },

                                    /**
                                     * Returns the class hierarchy for this object, with BaseCore being the last class in the array.
                                     *
                                     * @method _getClasses
                                     * @protected
                                     * @return {Function[]} An array of classes (constructor functions), making up the class hierarchy for this object.
                                     * This value is cached the first time the method, or _getAttrCfgs, is invoked. Subsequent invocations return the
                                     * cached value.
                                     */
                                    _getClasses : function() {
                                        if (!this._classes) {
                                            this._initHierarchyData();
                                        }
                                        return this._classes;
                                    },

                                    /**
                                     * Returns an aggregated set of attribute configurations, by traversing
                                     * the class hierarchy.
                                     *
                                     * @method _getAttrCfgs
                                     * @protected
                                     * @return {Object} The hash of attribute configurations, aggregated across classes in the hierarchy
                                     * This value is cached the first time the method, or _getClasses, is invoked. Subsequent invocations return
                                     * the cached value.
                                     */
                                    _getAttrCfgs : function() {
                                        if (!this._attrs) {
                                            this._initHierarchyData();
                                        }
                                        return this._attrs;
                                    },

                                    /**
                                     * A helper method used to isolate the attrs config for this instance to pass to `addAttrs`,
                                     * from the static cached ATTRS for the class.
                                     *
                                     * @method _getInstanceAttrCfgs
                                     * @private
                                     *
                                     * @param {Object} allCfgs The set of all attribute configurations for this instance.
                                     * Attributes will be removed from this set, if they belong to the filtered class, so
                                     * that by the time all classes are processed, allCfgs will be empty.
                                     *
                                     * @return {Object} The set of attributes to be added for this instance, suitable
                                     * for passing through to `addAttrs`.
                                     */
                                    _getInstanceAttrCfgs : function(allCfgs) {

                                        var cfgs = {},
                                            cfg,
                                            val,
                                            subAttr,
                                            subAttrs,
                                            subAttrPath,
                                            attr,
                                            attrCfg,
                                            allSubAttrs = allCfgs._subAttrs,
                                            attrCfgProperties = this._attrCfgHash();

                                        for (attr in allCfgs) {

                                            if (allCfgs.hasOwnProperty(attr) && attr !== "_subAttrs") {

                                                attrCfg = allCfgs[attr];

                                                // Need to isolate from allCfgs, because we're going to set values etc.
                                                cfg = cfgs[attr] = _wlmix({}, attrCfg, attrCfgProperties);

                                                val = cfg.value;

                                                if (val && (typeof val === "object")) {
                                                    this._cloneDefaultValue(attr, cfg);
                                                }

                                                if (allSubAttrs && allSubAttrs.hasOwnProperty(attr)) {
                                                    subAttrs = allCfgs._subAttrs[attr];

                                                    for (subAttrPath in subAttrs) {
                                                        subAttr = subAttrs[subAttrPath];

                                                        if (subAttr.path) {
                                                            O.setValue(cfg.value, subAttr.path, subAttr.value);
                                                        }
                                                    }
                                                }
                                            }
                                        }

                                        return cfgs;
                                    },

                                    /**
                                     * @method _filterAdHocAttrs
                                     * @private
                                     *
                                     * @param {Object} allAttrs The set of all attribute configurations for this instance.
                                     * Attributes will be removed from this set, if they belong to the filtered class, so
                                     * that by the time all classes are processed, allCfgs will be empty.
                                     * @param {Object} userVals The config object passed in by the user, from which adhoc attrs are to be filtered.
                                     * @return {Object} The set of adhoc attributes passed in, in the form
                                     * of an object with attribute name/configuration pairs.
                                     */
                                    _filterAdHocAttrs : function(allAttrs, userVals) {
                                        var adHocs,
                                            nonAttrs = this._nonAttrs,
                                            attr;

                                        if (userVals) {
                                            adHocs = {};
                                            for (attr in userVals) {
                                                if (!allAttrs[attr] && !nonAttrs[attr] && userVals.hasOwnProperty(attr)) {
                                                    adHocs[attr] = {
                                                        value:userVals[attr]
                                                    };
                                                }
                                            }
                                        }

                                        return adHocs;
                                    },

                                    /**
                                     * A helper method used by _getClasses and _getAttrCfgs, which determines both
                                     * the array of classes and aggregate set of attribute configurations
                                     * across the class hierarchy for the instance.
                                     *
                                     * @method _initHierarchyData
                                     * @private
                                     */
                                    _initHierarchyData : function() {

                                        var ctor = this.constructor,
                                            cachedClassData = ctor._CACHED_CLASS_DATA,
                                            c,
                                            i,
                                            l,
                                            attrCfg,
                                            attrCfgHash,
                                            needsAttrCfgHash = !ctor._ATTR_CFG_HASH,
                                            nonAttrsCfg,
                                            nonAttrs = {},
                                            classes = [],
                                            attrs = [];

                                        // Start with `this` instance's constructor.
                                        c = ctor;

                                        if (!cachedClassData) {

                                            while (c) {
                                                // Add to classes
                                                classes[classes.length] = c;

                                                // Add to attributes
                                                if (c.ATTRS) {
                                                    attrs[attrs.length] = c.ATTRS;
                                                }

                                                // Aggregate ATTR cfg whitelist.
                                                if (needsAttrCfgHash) {
                                                    attrCfg     = c._ATTR_CFG;
                                                    attrCfgHash = attrCfgHash || {};

                                                    if (attrCfg) {
                                                        for (i = 0, l = attrCfg.length; i < l; i += 1) {
                                                            attrCfgHash[attrCfg[i]] = true;
                                                        }
                                                    }
                                                }

                                                // Commenting out the if. We always aggregate, since we don't
                                                // know if we'll be needing this on the instance or not.
                                                // if (this._allowAdHocAttrs) {
                                                    nonAttrsCfg = c._NON_ATTRS_CFG;
                                                    if (nonAttrsCfg) {
                                                        for (i = 0, l = nonAttrsCfg.length; i < l; i++) {
                                                            nonAttrs[nonAttrsCfg[i]] = true;
                                                        }
                                                    }
                                                //}

                                                c = c.superclass ? c.superclass.constructor : null;
                                            }

                                            // Cache computed `_ATTR_CFG_HASH` on the constructor.
                                            if (needsAttrCfgHash) {
                                                ctor._ATTR_CFG_HASH = attrCfgHash;
                                            }

                                            cachedClassData = ctor._CACHED_CLASS_DATA = {
                                                classes : classes,
                                                nonAttrs : nonAttrs,
                                                attrs : this._aggregateAttrs(attrs)
                                            };

                                        }

                                        this._classes = cachedClassData.classes;
                                        this._attrs = cachedClassData.attrs;
                                        this._nonAttrs = cachedClassData.nonAttrs;
                                    },

                                    /**
                                     * Utility method to define the attribute hash used to filter/whitelist property mixes for
                                     * this class for iteration performance reasons.
                                     *
                                     * @method _attrCfgHash
                                     * @private
                                     */
                                    _attrCfgHash: function() {
                                        return this.constructor._ATTR_CFG_HASH;
                                    },

                                    /**
                                     * This method assumes that the value has already been checked to be an object.
                                     * Since it's on a critical path, we don't want to re-do the check.
                                     *
                                     * @method _cloneDefaultValue
                                     * @param {Object} cfg
                                     * @private
                                     */
                                    _cloneDefaultValue : function(attr, cfg) {

                                        var val = cfg.value,
                                            clone = cfg.cloneDefaultValue;

                                        if (clone === DEEP || clone === true) {
                                            Y.log('Cloning default value for attribute:' + attr, 'info', 'base');
                                            cfg.value = Y.clone(val);
                                        } else if (clone === SHALLOW) {
                                            Y.log('Merging default value for attribute:' + attr, 'info', 'base');
                                            cfg.value = Y.merge(val);
                                        } else if ((clone === undefined && (OBJECT_CONSTRUCTOR === val.constructor || L.isArray(val)))) {
                                            cfg.value = Y.clone(val);
                                        }
                                        // else if (clone === false), don't clone the static default value.
                                        // It's intended to be used by reference.
                                    },

                                    /**
                                     * A helper method, used by _initHierarchyData to aggregate
                                     * attribute configuration across the instances class hierarchy.
                                     *
                                     * The method will protect the attribute configuration value to protect the statically defined
                                     * default value in ATTRS if required (if the value is an object literal, array or the
                                     * attribute configuration has cloneDefaultValue set to shallow or deep).
                                     *
                                     * @method _aggregateAttrs
                                     * @private
                                     * @param {Array} allAttrs An array of ATTRS definitions across classes in the hierarchy
                                     * (subclass first, Base last)
                                     * @return {Object} The aggregate set of ATTRS definitions for the instance
                                     */
                                    _aggregateAttrs : function(allAttrs) {

                                        var attr,
                                            attrs,
                                            subAttrsHash,
                                            cfg,
                                            path,
                                            i,
                                            cfgPropsHash = this._attrCfgHash(),
                                            aggAttr,
                                            aggAttrs = {};

                                        if (allAttrs) {
                                            for (i = allAttrs.length-1; i >= 0; --i) {

                                                attrs = allAttrs[i];

                                                for (attr in attrs) {
                                                    if (attrs.hasOwnProperty(attr)) {

                                                        // PERF TODO: Do we need to merge here, since we're merging later in getInstanceAttrCfgs
                                                        // Should we move this down to only merge if we hit the path or valueFn ifs below?
                                                        cfg = _wlmix({}, attrs[attr], cfgPropsHash);

                                                        path = null;
                                                        if (attr.indexOf(DOT) !== -1) {
                                                            path = attr.split(DOT);
                                                            attr = path.shift();
                                                        }

                                                        aggAttr = aggAttrs[attr];

                                                        if (path && aggAttr && aggAttr.value) {

                                                            subAttrsHash = aggAttrs._subAttrs;

                                                            if (!subAttrsHash) {
                                                                subAttrsHash = aggAttrs._subAttrs = {};
                                                            }

                                                            if (!subAttrsHash[attr]) {
                                                                subAttrsHash[attr] = {};
                                                            }

                                                            subAttrsHash[attr][path.join(DOT)] = {
                                                                value: cfg.value,
                                                                path : path
                                                            };

                                                        } else if (!path) {

                                                            if (!aggAttr) {
                                                                aggAttrs[attr] = cfg;
                                                            } else {
                                                                if (aggAttr.valueFn && VALUE in cfg) {
                                                                    aggAttr.valueFn = null;
                                                                }

                                                                // Mix into existing config.
                                                                _wlmix(aggAttr, cfg, cfgPropsHash);
                                                            }
                                                        }
                                                    }
                                                }
                                            }
                                        }

                                        return aggAttrs;
                                    },

                                    /**
                                     * Initializes the class hierarchy for the instance, which includes
                                     * initializing attributes for each class defined in the class's
                                     * static <a href="#property_BaseCore.ATTRS">ATTRS</a> property and
                                     * invoking the initializer method on the prototype of each class in the hierarchy.
                                     *
                                     * @method _initHierarchy
                                     * @param {Object} userVals Object with configuration property name/value pairs
                                     * @private
                                     */
                                    _initHierarchy : function(userVals) {

                                        var lazy = this._lazyAddAttrs,
                                            constr,
                                            constrProto,
                                            i,
                                            l,
                                            ci,
                                            ei,
                                            el,
                                            ext,
                                            extProto,
                                            exts,
                                            instanceAttrs,
                                            initializers = [],
                                            classes = this._getClasses(),
                                            attrCfgs = this._getAttrCfgs(),
                                            cl = classes.length - 1;

                                        // Constructors
                                        for (ci = cl; ci >= 0; ci--) {

                                            constr = classes[ci];
                                            constrProto = constr.prototype;
                                            exts = constr._yuibuild && constr._yuibuild.exts;

                                            // Using INITIALIZER in hasOwnProperty check, for performance reasons (helps IE6 avoid GC thresholds when
                                            // referencing string literals). Not using it in apply, again, for performance "." is faster.

                                            if (constrProto.hasOwnProperty(INITIALIZER)) {
                                                // Store initializer while we're here and looping
                                                initializers[initializers.length] = constrProto.initializer;
                                            }

                                            if (exts) {
                                                for (ei = 0, el = exts.length; ei < el; ei++) {

                                                    ext = exts[ei];

                                                    // Ext Constructor
                                                    ext.apply(this, arguments);

                                                    extProto = ext.prototype;
                                                    if (extProto.hasOwnProperty(INITIALIZER)) {
                                                        // Store initializer while we're here and looping
                                                        initializers[initializers.length] = extProto.initializer;
                                                    }
                                                }
                                            }
                                        }

                                        // ATTRS
                                        instanceAttrs = this._getInstanceAttrCfgs(attrCfgs);

                                        if (this._preAddAttrs) {
                                            this._preAddAttrs(instanceAttrs, userVals, lazy);
                                        }

                                        if (this._allowAdHocAttrs) {
                                            this.addAttrs(this._filterAdHocAttrs(attrCfgs, userVals), userVals, lazy);
                                        }

                                        this.addAttrs(instanceAttrs, userVals, lazy);

                                        // Initializers
                                        for (i = 0, l = initializers.length; i < l; i++) {
                                            initializers[i].apply(this, arguments);
                                        }
                                    },

                                    /**
                                     * Destroys the class hierarchy for this instance by invoking
                                     * the destructor method on the prototype of each class in the hierarchy.
                                     *
                                     * @method _destroyHierarchy
                                     * @private
                                     */
                                    _destroyHierarchy : function() {
                                        var constr,
                                            constrProto,
                                            ci, cl, ei, el, exts, extProto,
                                            classes = this._getClasses();

                                        for (ci = 0, cl = classes.length; ci < cl; ci++) {
                                            constr = classes[ci];
                                            constrProto = constr.prototype;
                                            exts = constr._yuibuild && constr._yuibuild.exts;

                                            if (exts) {
                                                for (ei = 0, el = exts.length; ei < el; ei++) {
                                                    extProto = exts[ei].prototype;
                                                    if (extProto.hasOwnProperty(DESTRUCTOR)) {
                                                        extProto.destructor.apply(this, arguments);
                                                    }
                                                }
                                            }

                                            if (constrProto.hasOwnProperty(DESTRUCTOR)) {
                                                constrProto.destructor.apply(this, arguments);
                                            }
                                        }
                                    },

                                    /**
                                     * Default toString implementation. Provides the constructor NAME
                                     * and the instance guid, if set.
                                     *
                                     * @method toString
                                     * @return {String} String representation for this object
                                     */
                                    toString: function() {
                                        return this.name + "[" + Y.stamp(this, true) + "]";
                                    }
                                };

                                // Straightup augment, no wrapper functions
                                Y.mix(BaseCore, AttributeCore, false, null, 1);

                                // Fix constructor
                                BaseCore.prototype.constructor = BaseCore;

                                Y.BaseCore = BaseCore;