Move _unpack_models to widget.js and widget serialization to widget.py

IPython/html/static/widgets/js/widget.js

@@ -1,780 +1,806
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define(["widgets/js/manager",
         "underscore",
         "backbone",
         "jquery",
         "base/js/utils",
         "base/js/namespace",
 ], function(widgetmanager, _, Backbone, $, utils, IPython){
     "use strict";
 
+    var unpack_models = function unpack_models(value, model) {
+        /**
+         * Replace model ids with models recursively.
+         */
+        var unpacked;
+        if ($.isArray(value)) {
+            unpacked = [];
+            _.each(value, function(sub_value, key) {
+                unpacked.push(unpack_models(sub_value, model));
+            });
+            return Promise.all(unpacked);
+        } else if (value instanceof Object) {
+            unpacked = {};
+            _.each(value, function(sub_value, key) {
+                unpacked[key] = unpack_models(sub_value, model);
+            });
+            return utils.resolve_promises_dict(unpacked);
+        } else if (typeof value === 'string' && value.slice(0,10) === "IPY_MODEL_") {
+            // get_model returns a promise already
+            return model.widget_manager.get_model(value.slice(10, value.length));
+        } else {
+            return Promise.resolve(value);
+        }
+    };
+
     var WidgetModel = Backbone.Model.extend({
         constructor: function (widget_manager, model_id, comm) {
             /**
              * Constructor
              *
              * Creates a WidgetModel instance.
              *
              * Parameters
              * ----------
              * widget_manager : WidgetManager instance
              * model_id : string
              *      An ID unique to this model.
              * comm : Comm instance (optional)
              */
             this.widget_manager = widget_manager;
             this.state_change = Promise.resolve();
             this._buffered_state_diff = {};
             this.pending_msgs = 0;
             this.msg_buffer = null;
             this.state_lock = null;
             this.id = model_id;
             this.views = {};
             this._resolve_received_state = {};
 
             if (comm !== undefined) {
                 // Remember comm associated with the model.
                 this.comm = comm;
                 comm.model = this;
 
                 // Hook comm messages up to model.
                 comm.on_close($.proxy(this._handle_comm_closed, this));
                 comm.on_msg($.proxy(this._handle_comm_msg, this));
 
                 // Assume the comm is alive.
                 this.set_comm_live(true);
             } else {
                 this.set_comm_live(false);
             }
 
             // Listen for the events that lead to the websocket being terminated.
             var that = this;
             var died = function() {
                 that.set_comm_live(false);
             };
             widget_manager.notebook.events.on('kernel_disconnected.Kernel', died);
             widget_manager.notebook.events.on('kernel_killed.Kernel', died);
             widget_manager.notebook.events.on('kernel_restarting.Kernel', died);
             widget_manager.notebook.events.on('kernel_dead.Kernel', died);
 
             return Backbone.Model.apply(this);
         },
 
         send: function (content, callbacks, buffers) {
             /**
              * Send a custom msg over the comm.
              */
             if (this.comm !== undefined) {
                 var data = {method: 'custom', content: content};
                 this.comm.send(data, callbacks, {}, buffers);
                 this.pending_msgs++;
             }
         },
 
         request_state: function(callbacks) {
             /** 
              * Request a state push from the back-end.
              */
             if (!this.comm) {
                 console.error("Could not request_state because comm doesn't exist!");
                 return;
             }
 
             var msg_id = this.comm.send({method: 'request_state'}, callbacks || this.widget_manager.callbacks());
 
             // Promise that is resolved when a state is received
             // from the back-end.
             var that = this;
             var received_state = new Promise(function(resolve) {
                 that._resolve_received_state[msg_id] = resolve;
             });
             return received_state;
         },
 
         set_comm_live: function(live) {
             /** 
              * Change the comm_live state of the model.
              */
             if (this.comm_live === undefined || this.comm_live != live) {
                 this.comm_live = live;
                 this.trigger(live ? 'comm:live' : 'comm:dead', {model: this});
             }
         },
 
         close: function(comm_closed) {
             /**
              * Close model
              */
             if (this.comm && !comm_closed) {
                 this.comm.close();
             }
             this.stopListening();
             this.trigger('destroy', this);
             delete this.comm.model; // Delete ref so GC will collect widget model.
             delete this.comm;
             delete this.model_id; // Delete id from model so widget manager cleans up.
             _.each(this.views, function(v, id, views) {
                 v.then(function(view) {
                     view.remove();
                     delete views[id];
                 });
             });
         },
 
         _handle_comm_closed: function (msg) {
             /** 
              * Handle when a widget is closed.
              */
             this.trigger('comm:close');
             this.close(true);
         },
 
         _handle_comm_msg: function (msg) {
             /**
              * Handle incoming comm msg.
              */
             var method = msg.content.data.method;
             
             var that = this;
             switch (method) {
                 case 'update':
                     this.state_change = this.state_change
                         .then(function() {
                             var state = msg.content.data.state || {};
                             var buffer_keys = msg.content.data.buffers || [];
                             var buffers = msg.buffers || [];
                             for (var i=0; i<buffer_keys.length; i++) {
                                 state[buffer_keys[i]] = buffers[i];
                             }
 
                             // deserialize fields that have custom deserializers
                             var serializers = that.constructor.serializers;
                             if (serializers) {
                                 for (var k in state) {
                                     if (serializers[k] && serializers[k].deserialize) {
                                         state[k] = (serializers[k].deserialize)(state[k], that);
                                     }
                                 }
                             }
                             return utils.resolve_promises_dict(state);
                         }).then(function(state) {
                             return that.set_state(state);
                         }).catch(utils.reject("Couldn't process update msg for model id '" + String(that.id) + "'", true))
                         .then(function() {
                             var parent_id = msg.parent_header.msg_id;
                             if (that._resolve_received_state[parent_id] !== undefined) {
                                 that._resolve_received_state[parent_id].call();
                                 delete that._resolve_received_state[parent_id];
                             }
                         }).catch(utils.reject("Couldn't resolve state request promise", true));
                     break;
                 case 'custom':
                     this.trigger('msg:custom', msg.content.data.content, msg.buffers);
                     break;
                 case 'display':
                     this.state_change = this.state_change.then(function() {
                         that.widget_manager.display_view(msg, that);
                     }).catch(utils.reject('Could not process display view msg', true));
                     break;
             }
         },
 
         set_state: function (state) {
             var that = this;
             // Handle when a widget is updated via the python side.
             return new Promise(function(resolve, reject) {
                 that.state_lock = state;
                 try {
                     WidgetModel.__super__.set.call(that, state);
                 } finally {
                     that.state_lock = null;
                 }
                 resolve();
             }).catch(utils.reject("Couldn't set model state", true));
         },
 
         get_state: function() {
             // Get the serializable state of the model.
             // Equivalent to Backbone.Model.toJSON()
             return _.clone(this.attributes);
         },
         
         _handle_status: function (msg, callbacks) {
             /**
              * Handle status msgs.
              *
              * execution_state : ('busy', 'idle', 'starting')
              */
             if (this.comm !== undefined) {
                 if (msg.content.execution_state ==='idle') {
                     // Send buffer if this message caused another message to be
                     // throttled.
                     if (this.msg_buffer !== null &&
                         (this.get('msg_throttle') || 3) === this.pending_msgs) {
                         var data = {method: 'backbone', sync_method: 'update', sync_data: this.msg_buffer};
                         this.comm.send(data, callbacks);
                         this.msg_buffer = null;
                     } else {
                         --this.pending_msgs;
                     }
                 }
             }
         },
 
         callbacks: function(view) {
             /**
              * Create msg callbacks for a comm msg.
              */
             var callbacks = this.widget_manager.callbacks(view);
 
             if (callbacks.iopub === undefined) {
                 callbacks.iopub = {};
             }
 
             var that = this;
             callbacks.iopub.status = function (msg) {
                 that._handle_status(msg, callbacks);
             };
             return callbacks;
         },
 
         set: function(key, val, options) {
             /**
              * Set a value.
              */
             var return_value = WidgetModel.__super__.set.apply(this, arguments);
 
             // Backbone only remembers the diff of the most recent set()
             // operation.  Calling set multiple times in a row results in a 
             // loss of diff information.  Here we keep our own running diff.
             this._buffered_state_diff = $.extend(this._buffered_state_diff, this.changedAttributes() || {});
             return return_value;
         },
 
         sync: function (method, model, options) {
             /**
              * Handle sync to the back-end.  Called when a model.save() is called.
              *
              * Make sure a comm exists.
 
              * Parameters
              * ----------
              * method : create, update, patch, delete, read
              *   create/update always send the full attribute set
              *   patch - only send attributes listed in options.attrs, and if we are queuing
              *     up messages, combine with previous messages that have not been sent yet
              * model : the model we are syncing
              *   will normally be the same as `this`
              * options : dict
              *   the `attrs` key, if it exists, gives an {attr: value} dict that should be synced,
              *   otherwise, sync all attributes
              * 
              */
             var error = options.error || function() {
                 console.error('Backbone sync error:', arguments);
             };
             if (this.comm === undefined) {
                 error();
                 return false;
             }
 
             var attrs = (method === 'patch') ? options.attrs : model.get_state(options);
 
             // the state_lock lists attributes that are currently be changed right now from a kernel message
             // we don't want to send these non-changes back to the kernel, so we delete them out of attrs
             // (but we only delete them if the value hasn't changed from the value stored in the state_lock
             if (this.state_lock !== null) {
                 var keys = Object.keys(this.state_lock);
                 for (var i=0; i<keys.length; i++) {
                     var key = keys[i];
                     if (attrs[key] === this.state_lock[key]) {
                         delete attrs[key];
                     }
                 }
             }
             
             if (_.size(attrs) > 0) {
 
                 // If this message was sent via backbone itself, it will not
                 // have any callbacks.  It's important that we create callbacks
                 // so we can listen for status messages, etc...
                 var callbacks = options.callbacks || this.callbacks();
 
                 // Check throttle.
                 if (this.pending_msgs >= (this.get('msg_throttle') || 3)) {
                     // The throttle has been exceeded, buffer the current msg so
                     // it can be sent once the kernel has finished processing 
                     // some of the existing messages.
                     
                     // Combine updates if it is a 'patch' sync, otherwise replace updates
                     switch (method) {
                         case 'patch':
                             this.msg_buffer = $.extend(this.msg_buffer || {}, attrs);
                             break;
                         case 'update':
                         case 'create':
                             this.msg_buffer = attrs;
                             break;
                         default:
                             error();
                             return false;
                     }
                     this.msg_buffer_callbacks = callbacks;
 
                 } else {
                     // We haven't exceeded the throttle, send the message like 
                     // normal.
                     this.send_sync_message(attrs, callbacks);
                     this.pending_msgs++;
                 }
             }
             // Since the comm is a one-way communication, assume the message 
             // arrived.  Don't call success since we don't have a model back from the server
             // this means we miss out on the 'sync' event.
             this._buffered_state_diff = {};
         },
 
 
         send_sync_message: function(attrs, callbacks) {
             // prepare and send a comm message syncing attrs
             var that = this;
             // first, build a state dictionary with key=the attribute and the value
             // being the value or the promise of the serialized value
             var serializers = this.constructor.serializers;
             if (serializers) {
                 for (k in attrs) {
                     if (serializers[k] && serializers[k].serialize) {
                         attrs[k] = (serializers[k].serialize)(attrs[k], this);
                     }
                 }
             }
             utils.resolve_promises_dict(attrs).then(function(state) {
                 // get binary values, then send
                 var keys = Object.keys(state);
                 var buffers = [];
                 var buffer_keys = [];
                 for (var i=0; i<keys.length; i++) {
                     var key = keys[i];
                     var value = state[key];
                     if (value.buffer instanceof ArrayBuffer
                         || value instanceof ArrayBuffer) {
                         buffers.push(value);
                         buffer_keys.push(key);
                         delete state[key];
                     }
                 }
                 that.comm.send({method: 'backbone', sync_data: state, buffer_keys: buffer_keys}, callbacks, {}, buffers);
             }).catch(function(error) {
                 that.pending_msgs--;
                 return (utils.reject("Couldn't send widget sync message", true))(error);
             });
         },
         
         save_changes: function(callbacks) {
             /**
              * Push this model's state to the back-end
              *
              * This invokes a Backbone.Sync.
              */
             this.save(this._buffered_state_diff, {patch: true, callbacks: callbacks});
         },
 
         on_some_change: function(keys, callback, context) {
             /**
              * on_some_change(["key1", "key2"], foo, context) differs from
              * on("change:key1 change:key2", foo, context).
              * If the widget attributes key1 and key2 are both modified, 
              * the second form will result in foo being called twice
              * while the first will call foo only once.
              */
             this.on('change', function() {
                 if (keys.some(this.hasChanged, this)) {
                     callback.apply(context);
                 }
             }, this);
 
         },
 
         toJSON: function(options) {
             /**
              * Serialize the model.  See the types.js deserialization function
              * and the kernel-side serializer/deserializer
              */
             return "IPY_MODEL_"+this.id;
         }
     });
     widgetmanager.WidgetManager.register_widget_model('WidgetModel', WidgetModel);
 
 
     var WidgetView = Backbone.View.extend({
         initialize: function(parameters) {
             /**
              * Public constructor.
              */
             this.model.on('change',this.update,this);
 
             // Bubble the comm live events.
             this.model.on('comm:live', function() {
                 this.trigger('comm:live', this);
             }, this);
             this.model.on('comm:dead', function() {
                 this.trigger('comm:dead', this);
             }, this);
 
             this.options = parameters.options;
             this.on('displayed', function() { 
                 this.is_displayed = true; 
             }, this);
         },
 
         update: function(){
             /**
              * Triggered on model change.
              *
              * Update view to be consistent with this.model
              */
         },
 
         create_child_view: function(child_model, options) {
             /**
              * Create and promise that resolves to a child view of a given model
              */
             var that = this;
             options = $.extend({ parent: this }, options || {});
             return this.model.widget_manager.create_view(child_model, options).catch(utils.reject("Couldn't create child view", true));
         },
 
         callbacks: function(){
             /**
              * Create msg callbacks for a comm msg.
              */
             return this.model.callbacks(this);
         },
 
         render: function(){
             /**
              * Render the view.
              *
              * By default, this is only called the first time the view is created
              */
         },
 
         send: function (content, buffers) {
             /**
              * Send a custom msg associated with this view.
              */
             this.model.send(content, this.callbacks(), buffers);
         },
 
         touch: function () {
             this.model.save_changes(this.callbacks());
         },
 
         after_displayed: function (callback, context) {
             /**
              * Calls the callback right away is the view is already displayed
              * otherwise, register the callback to the 'displayed' event.
              */
             if (this.is_displayed) {
                 callback.apply(context);
             } else {
                 this.on('displayed', callback, context);
             }
         },
 
         remove: function () {
             // Raise a remove event when the view is removed.
             WidgetView.__super__.remove.apply(this, arguments);
             this.trigger('remove');
         }
     });
 
 
     var DOMWidgetView = WidgetView.extend({
         initialize: function (parameters) {
             /**
              * Public constructor
              */
             DOMWidgetView.__super__.initialize.apply(this, [parameters]);
             this.model.on('change:visible', this.update_visible, this);
             this.model.on('change:_css', this.update_css, this);
 
             this.model.on('change:_dom_classes', function(model, new_classes) {
                 var old_classes = model.previous('_dom_classes');
                 this.update_classes(old_classes, new_classes);
             }, this);
 
             this.model.on('change:color', function (model, value) { 
                 this.update_attr('color', value); }, this);
 
             this.model.on('change:background_color', function (model, value) { 
                 this.update_attr('background', value); }, this);
 
             this.model.on('change:width', function (model, value) { 
                 this.update_attr('width', value); }, this);
 
             this.model.on('change:height', function (model, value) { 
                 this.update_attr('height', value); }, this);
 
             this.model.on('change:border_color', function (model, value) { 
                 this.update_attr('border-color', value); }, this);
 
             this.model.on('change:border_width', function (model, value) { 
                 this.update_attr('border-width', value); }, this);
 
             this.model.on('change:border_style', function (model, value) { 
                 this.update_attr('border-style', value); }, this);
 
             this.model.on('change:font_style', function (model, value) { 
                 this.update_attr('font-style', value); }, this);
 
             this.model.on('change:font_weight', function (model, value) { 
                 this.update_attr('font-weight', value); }, this);
 
             this.model.on('change:font_size', function (model, value) { 
                 this.update_attr('font-size', this._default_px(value)); }, this);
 
             this.model.on('change:font_family', function (model, value) { 
                 this.update_attr('font-family', value); }, this);
 
             this.model.on('change:padding', function (model, value) { 
                 this.update_attr('padding', value); }, this);
 
             this.model.on('change:margin', function (model, value) { 
                 this.update_attr('margin', this._default_px(value)); }, this);
 
             this.model.on('change:border_radius', function (model, value) { 
                 this.update_attr('border-radius', this._default_px(value)); }, this);
 
             this.after_displayed(function() {
                 this.update_visible(this.model, this.model.get("visible"));
                 this.update_classes([], this.model.get('_dom_classes'));
                 
                 this.update_attr('color', this.model.get('color'));
                 this.update_attr('background', this.model.get('background_color'));
                 this.update_attr('width', this.model.get('width'));
                 this.update_attr('height', this.model.get('height'));
                 this.update_attr('border-color', this.model.get('border_color'));
                 this.update_attr('border-width', this.model.get('border_width'));
                 this.update_attr('border-style', this.model.get('border_style'));
                 this.update_attr('font-style', this.model.get('font_style'));
                 this.update_attr('font-weight', this.model.get('font_weight'));
                 this.update_attr('font-size', this._default_px(this.model.get('font_size')));
                 this.update_attr('font-family', this.model.get('font_family'));
                 this.update_attr('padding', this.model.get('padding'));
                 this.update_attr('margin', this._default_px(this.model.get('margin')));
                 this.update_attr('border-radius', this._default_px(this.model.get('border_radius')));
 
                 this.update_css(this.model, this.model.get("_css"));
             }, this);
         },
 
         _default_px: function(value) {
             /**
              * Makes browser interpret a numerical string as a pixel value.
              */
             if (value && /^\d+\.?(\d+)?$/.test(value.trim())) {
                 return value.trim() + 'px';
             }
             return value;
         },
 
         update_attr: function(name, value) {
             /**
              * Set a css attr of the widget view.
              */
             this.$el.css(name, value);
         },
 
         update_visible: function(model, value) {
             /**
              * Update visibility
              */
             switch(value) {
                 case null: // python None
                     this.$el.show().css('visibility', 'hidden'); break;
                 case false:
                     this.$el.hide(); break;
                 case true:
                     this.$el.show().css('visibility', ''); break;
             }
          },
 
         update_css: function (model, css) {
             /**
              * Update the css styling of this view.
              */
             if (css === undefined) {return;}
             for (var i = 0; i < css.length; i++) {
                 // Apply the css traits to all elements that match the selector.
                 var selector = css[i][0];
                 var elements = this._get_selector_element(selector);
                 if (elements.length > 0) {
                     var trait_key = css[i][1];
                     var trait_value = css[i][2];
                     elements.css(trait_key ,trait_value);
                 }
             }
         },
 
         update_classes: function (old_classes, new_classes, $el) {
             /**
              * Update the DOM classes applied to an element, default to this.$el.
              */
             if ($el===undefined) {
                 $el = this.$el;
             }
             _.difference(old_classes, new_classes).map(function(c) {$el.removeClass(c);})
             _.difference(new_classes, old_classes).map(function(c) {$el.addClass(c);})
         },
 
         update_mapped_classes: function(class_map, trait_name, previous_trait_value, $el) {
             /**
              * Update the DOM classes applied to the widget based on a single
              * trait's value.
              *
              * Given a trait value classes map, this function automatically
              * handles applying the appropriate classes to the widget element
              * and removing classes that are no longer valid.
              *
              * Parameters
              * ----------
              * class_map: dictionary
              *  Dictionary of trait values to class lists.
              *  Example:
              *      {
              *          success: ['alert', 'alert-success'],
              *          info: ['alert', 'alert-info'],
              *          warning: ['alert', 'alert-warning'],
              *          danger: ['alert', 'alert-danger']
              *      };
              * trait_name: string
              *  Name of the trait to check the value of.
              * previous_trait_value: optional string, default ''
              *  Last trait value
              * $el: optional jQuery element handle, defaults to this.$el
              *  Element that the classes are applied to.
              */
             var key = previous_trait_value;
             if (key === undefined) {
                 key = this.model.previous(trait_name);
             }
             var old_classes = class_map[key] ? class_map[key] : [];
             key = this.model.get(trait_name);
             var new_classes = class_map[key] ? class_map[key] : [];
 
             this.update_classes(old_classes, new_classes, $el || this.$el);
         },
         
         _get_selector_element: function (selector) {
             /**
              * Get the elements via the css selector.
              */
             var elements;
             if (!selector) {
                 elements = this.$el;
             } else {
                 elements = this.$el.find(selector).addBack(selector);
             }
             return elements;
         },
 
         typeset: function(element, text){
             utils.typeset.apply(null, arguments);
         },
     });
 
 
     var ViewList = function(create_view, remove_view, context) {
         /**
          * - create_view and remove_view are default functions called when adding or removing views
          * - create_view takes a model and returns a view or a promise for a view for that model
          * - remove_view takes a view and destroys it (including calling `view.remove()`)
          * - each time the update() function is called with a new list, the create and remove
          *   callbacks will be called in an order so that if you append the views created in the
          *   create callback and remove the views in the remove callback, you will duplicate 
          *   the order of the list.
          * - the remove callback defaults to just removing the view (e.g., pass in null for the second parameter)
          * - the context defaults to the created ViewList.  If you pass another context, the create and remove
          *   will be called in that context.
          */
 
         this.initialize.apply(this, arguments);
     };
 
     _.extend(ViewList.prototype, {
         initialize: function(create_view, remove_view, context) {
             this._handler_context = context || this;
             this._models = [];
             this.views = []; // list of promises for views
             this._create_view = create_view;
             this._remove_view = remove_view || function(view) {view.remove();};
         },
 
         update: function(new_models, create_view, remove_view, context) {
             /**
              * the create_view, remove_view, and context arguments override the defaults
              * specified when the list is created.
              * after this function, the .views attribute is a list of promises for views
              * if you want to perform some action on the list of views, do something like
              * `Promise.all(myviewlist.views).then(function(views) {...});`
              */
             var remove = remove_view || this._remove_view;
             var create = create_view || this._create_view;
             context = context || this._handler_context;
             var i = 0;
             // first, skip past the beginning of the lists if they are identical
             for (; i < new_models.length; i++) {
                 if (i >= this._models.length || new_models[i] !== this._models[i]) {
                     break;
                 }
             }
             
             var first_removed = i;
             // Remove the non-matching items from the old list.
             var removed = this.views.splice(first_removed, this.views.length-first_removed);
             for (var j = 0; j < removed.length; j++) {
                 removed[j].then(function(view) {
                     remove.call(context, view)
                 });
             }
 
             // Add the rest of the new list items.
             for (; i < new_models.length; i++) {
                 this.views.push(Promise.resolve(create.call(context, new_models[i])));
             }
             // make a copy of the input array
             this._models = new_models.slice();
         },
 
         remove: function() {
             /**
              * removes every view in the list; convenience function for `.update([])`
              * that should be faster
              * returns a promise that resolves after this removal is done
              */
             var that = this;
             return Promise.all(this.views).then(function(views) {
                 for (var i = 0; i < that.views.length; i++) {
                     that._remove_view.call(that._handler_context, views[i]);
                 }
                 that.views = [];
                 that._models = [];
             });
         },
     });
 
     var widget = {
+        'unpack_models': unpack_models,
         'WidgetModel': WidgetModel,
         'WidgetView': WidgetView,
         'DOMWidgetView': DOMWidgetView,
         'ViewList': ViewList,
     };
 
     // For backwards compatability.
     $.extend(IPython, widget);
 
     return widget;
 });

IPython/html/static/widgets/js/widget_box.js

@@ -1,187 +1,162
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define([
     "widgets/js/widget",
     "jqueryui",
     "underscore",
     "base/js/utils",
     "bootstrap",
 ], function(widget, $, _, utils){
     "use strict";
-    var unpack_models = function unpack_models(value, model) {
-        /**
-         * Replace model ids with models recursively.
-         */
-        var unpacked;
-        if ($.isArray(value)) {
-            unpacked = [];
-            _.each(value, function(sub_value, key) {
-                unpacked.push(unpack_models(sub_value, model));
-            });
-            return Promise.all(unpacked);
-        } else if (value instanceof Object) {
-            unpacked = {};
-            _.each(value, function(sub_value, key) {
-                unpacked[key] = unpack_models(sub_value, model);
-            });
-            return utils.resolve_promises_dict(unpacked);
-        } else if (typeof value === 'string' && value.slice(0,10) === "IPY_MODEL_") {
-            // get_model returns a promise already
-            return model.widget_manager.get_model(value.slice(10, value.length));
-        } else {
-            return Promise.resolve(value);
-        }
-    };
 
     var BoxModel = widget.WidgetModel.extend({}, {
         serializers: _.extend({
-            children: {deserialize: unpack_models}
+            children: {deserialize: widget.unpack_models}
         }, widget.WidgetModel.serializers)
     });
 
     var BoxView = widget.DOMWidgetView.extend({
         initialize: function(){
             /**
              * Public constructor
              */
             BoxView.__super__.initialize.apply(this, arguments);
             this.children_views = new widget.ViewList(this.add_child_model, null, this);
             this.listenTo(this.model, 'change:children', function(model, value) {
                 this.children_views.update(value);
             }, this);
             this.listenTo(this.model, 'change:overflow_x', function(model, value) {
                 this.update_overflow_x();
             }, this);
             this.listenTo(this.model, 'change:overflow_y', function(model, value) {
                 this.update_overflow_y();
             }, this);
             this.listenTo(this.model, 'change:box_style', function(model, value) {
                 this.update_box_style();
             }, this);
         },
 
         update_attr: function(name, value) {
             /**
              * Set a css attr of the widget view.
              */
             this.$box.css(name, value);
         },
 
         render: function(){
             /**
              * Called when view is rendered.
              */
             this.$box = this.$el;
             this.$box.addClass('widget-box');
             this.children_views.update(this.model.get('children'));
             this.update_overflow_x();
             this.update_overflow_y();
             this.update_box_style('');
         },
 
         update_overflow_x: function() {
             /**
              * Called when the x-axis overflow setting is changed.
              */
             this.$box.css('overflow-x', this.model.get('overflow_x'));
         },
 
         update_overflow_y: function() {
             /**
              * Called when the y-axis overflow setting is changed.
              */
             this.$box.css('overflow-y', this.model.get('overflow_y'));
         },
 
         update_box_style: function(previous_trait_value) {
             var class_map = {
                 success: ['alert', 'alert-success'],
                 info: ['alert', 'alert-info'],
                 warning: ['alert', 'alert-warning'],
                 danger: ['alert', 'alert-danger']
             };
             this.update_mapped_classes(class_map, 'box_style', previous_trait_value, this.$box);
         },
         
         add_child_model: function(model) {
             /**
              * Called when a model is added to the children list.
              */
             var that = this;
             var dummy = $('<div/>');
             that.$box.append(dummy);
             return this.create_child_view(model).then(function(view) {
                 dummy.replaceWith(view.el);
 
                 // Trigger the displayed event of the child view.
                 that.after_displayed(function() {
                     view.trigger('displayed');
                 });
                 return view;
             }).catch(utils.reject("Couldn't add child view to box", true));
         },
         
         remove: function() {
             /**
              * We remove this widget before removing the children as an optimization
              * we want to remove the entire container from the DOM first before
              * removing each individual child separately.
              */
             BoxView.__super__.remove.apply(this, arguments);
             this.children_views.remove();
         },
     });
 
 
     var FlexBoxView = BoxView.extend({
         render: function(){
             FlexBoxView.__super__.render.apply(this);
             this.listenTo(this.model, 'change:orientation', this.update_orientation, this);
             this.listenTo(this.model, 'change:flex', this._flex_changed, this);
             this.listenTo(this.model, 'change:pack', this._pack_changed, this);
             this.listenTo(this.model, 'change:align', this._align_changed, this);
             this._flex_changed();
             this._pack_changed();
             this._align_changed();
             this.update_orientation();
         },
 
         update_orientation: function(){
             var orientation = this.model.get("orientation");
             if (orientation == "vertical") {
                 this.$box.removeClass("hbox").addClass("vbox");
             } else {
                 this.$box.removeClass("vbox").addClass("hbox");
             }
         },
 
         _flex_changed: function(){
             if (this.model.previous('flex')) {
                 this.$box.removeClass('box-flex' + this.model.previous('flex'));
             }
             this.$box.addClass('box-flex' + this.model.get('flex'));
         },
 
         _pack_changed: function(){
             if (this.model.previous('pack')) {
                 this.$box.removeClass(this.model.previous('pack'));
             }
             this.$box.addClass(this.model.get('pack'));
         },
 
         _align_changed: function(){
             if (this.model.previous('align')) {
                 this.$box.removeClass('align-' + this.model.previous('align'));
             }
             this.$box.addClass('align-' + this.model.get('align'));
         },
     });
 
     return {
-        'unpack_models': unpack_models,
         'BoxModel': BoxModel,
         'BoxView': BoxView,
         'FlexBoxView': FlexBoxView,
     };
 });

IPython/html/widgets/__init__.py

@@ -1,40 +1,40
-from .widget import Widget, DOMWidget, CallbackDispatcher, register
+from .widget import Widget, DOMWidget, CallbackDispatcher, register, widget_serialization
 
 from .trait_types import Color
 
 from .widget_bool import Checkbox, ToggleButton, Valid
 from .widget_button import Button
 from .widget_box import Box, FlexBox, HBox, VBox
 from .widget_float import FloatText, BoundedFloatText, FloatSlider, FloatProgress, FloatRangeSlider
 from .widget_image import Image
 from .widget_int import IntText, BoundedIntText, IntSlider, IntProgress, IntRangeSlider
 from .widget_output import Output
 from .widget_selection import RadioButtons, ToggleButtons, Dropdown, Select, SelectMultiple
 from .widget_selectioncontainer import Tab, Accordion
 from .widget_string import HTML, Latex, Text, Textarea
 from .interaction import interact, interactive, fixed, interact_manual
 from .widget_link import jslink, jsdlink
 
 # Deprecated classes
 from .widget_bool import CheckboxWidget, ToggleButtonWidget
 from .widget_button import ButtonWidget
 from .widget_box import ContainerWidget
 from .widget_float import FloatTextWidget, BoundedFloatTextWidget, FloatSliderWidget, FloatProgressWidget
 from .widget_image import ImageWidget
 from .widget_int import IntTextWidget, BoundedIntTextWidget, IntSliderWidget, IntProgressWidget
 from .widget_selection import RadioButtonsWidget, ToggleButtonsWidget, DropdownWidget, SelectWidget
 from .widget_selectioncontainer import TabWidget, AccordionWidget
 from .widget_string import HTMLWidget, LatexWidget, TextWidget, TextareaWidget
 
 # We use warn_explicit so we have very brief messages without file or line numbers.
 # The concern is that file or line numbers will confuse the interactive user.
 # To ignore this warning, do:
 #
 #     from warnings import filterwarnings
 #     filterwarnings('ignore', module='IPython.html.widgets')
 
 from warnings import warn_explicit
 __warningregistry__ = {}
 warn_explicit("IPython widgets are experimental and may change in the future.",
               FutureWarning, '', 0, module = 'IPython.html.widgets',
               registry = __warningregistry__, module_globals = globals)

IPython/html/widgets/widget.py

@@ -1,497 +1,524
 """Base Widget class.  Allows user to create widgets in the back-end that render
 in the IPython notebook front-end.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from contextlib import contextmanager
 import collections
 
 from IPython.core.getipython import get_ipython
 from IPython.kernel.comm import Comm
 from IPython.config import LoggingConfigurable
 from IPython.utils.importstring import import_item
 from IPython.utils.traitlets import Unicode, Dict, Instance, Bool, List, \
     CaselessStrEnum, Tuple, CUnicode, Int, Set
 from IPython.utils.py3compat import string_types
 from .trait_types import Color
 
+
+def _widget_to_json(x):
+    if isinstance(x, dict):
+        return {k: _widget_to_json(v) for k, v in x.items()}
+    elif isinstance(x, (list, tuple)):
+        return [_widget_to_json(v) for v in x]
+    elif isinstance(x, Widget):
+        return "IPY_MODEL_" + x.model_id
+    else:
+        return x
+
+def _json_to_widget(x):
+    if isinstance(x, dict):
+        return {k: _json_to_widget(v) for k, v in x.items()}
+    elif isinstance(x, (list, tuple)):
+        return [_json_to_widget(v) for v in x]
+    elif isinstance(x, string_types) and x.startswith('IPY_MODEL_') and x[10:] in Widget.widgets:
+        return Widget.widgets[x[10:]]
+    else:
+        return x
+
+widget_serialization = {
+    'from_json': _json_to_widget,
+    'to_json': _widget_to_json
+}
+
+
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 class CallbackDispatcher(LoggingConfigurable):
     """A structure for registering and running callbacks"""
     callbacks = List()
     
     def __call__(self, *args, **kwargs):
         """Call all of the registered callbacks."""
         value = None
         for callback in self.callbacks:
             try:
                 local_value = callback(*args, **kwargs)
             except Exception as e:
                 ip = get_ipython()
                 if ip is None:
                     self.log.warn("Exception in callback %s: %s", callback, e, exc_info=True)
                 else:
                     ip.showtraceback()
             else:
                 value = local_value if local_value is not None else value
         return value
 
     def register_callback(self, callback, remove=False):
         """(Un)Register a callback
 
         Parameters
         ----------
         callback: method handle
             Method to be registered or unregistered.
         remove=False: bool
             Whether to unregister the callback."""
         
         # (Un)Register the callback.
         if remove and callback in self.callbacks:
             self.callbacks.remove(callback)
         elif not remove and callback not in self.callbacks:
             self.callbacks.append(callback)
 
 def _show_traceback(method):
     """decorator for showing tracebacks in IPython"""
     def m(self, *args, **kwargs):
         try:
             return(method(self, *args, **kwargs))
         except Exception as e:
             ip = get_ipython()
             if ip is None:
                 self.log.warn("Exception in widget method %s: %s", method, e, exc_info=True)
             else:
                 ip.showtraceback()
     return m
 
 
 def register(key=None):
     """Returns a decorator registering a widget class in the widget registry. 
     If no key is provided, the class name is used as a key. A key is
     provided for each core IPython widget so that the frontend can use
     this key regardless of the language of the kernel"""
     def wrap(widget):
         l = key if key is not None else widget.__module__ + widget.__name__
         Widget.widget_types[l] = widget
         return widget
     return wrap
 
 
 class Widget(LoggingConfigurable):
     #-------------------------------------------------------------------------
     # Class attributes
     #-------------------------------------------------------------------------
     _widget_construction_callback = None
     widgets = {}
     widget_types = {}
 
     @staticmethod
     def on_widget_constructed(callback):
         """Registers a callback to be called when a widget is constructed.
 
         The callback must have the following signature:
         callback(widget)"""
         Widget._widget_construction_callback = callback
 
     @staticmethod
     def _call_widget_constructed(widget):
         """Static method, called when a widget is constructed."""
         if Widget._widget_construction_callback is not None and callable(Widget._widget_construction_callback):
             Widget._widget_construction_callback(widget)
 
     @staticmethod
     def handle_comm_opened(comm, msg):
         """Static method, called when a widget is constructed."""
         widget_class = import_item(msg['content']['data']['widget_class'])
         widget = widget_class(comm=comm)
 
 
     #-------------------------------------------------------------------------
     # Traits
     #-------------------------------------------------------------------------
     _model_module = Unicode(None, allow_none=True, help="""A requirejs module name
         in which to find _model_name. If empty, look in the global registry.""")
     _model_name = Unicode('WidgetModel', help="""Name of the backbone model 
         registered in the front-end to create and sync this widget with.""")
     _view_module = Unicode(help="""A requirejs module in which to find _view_name.
         If empty, look in the global registry.""", sync=True)
     _view_name = Unicode(None, allow_none=True, help="""Default view registered in the front-end
         to use to represent the widget.""", sync=True)
     comm = Instance('IPython.kernel.comm.Comm', allow_none=True)
     
     msg_throttle = Int(3, sync=True, help="""Maximum number of msgs the 
         front-end can send before receiving an idle msg from the back-end.""")
     
     version = Int(0, sync=True, help="""Widget's version""")
     keys = List()
     def _keys_default(self):
         return [name for name in self.traits(sync=True)]
     
     _property_lock = Tuple((None, None))
     _send_state_lock = Int(0)
     _states_to_send = Set()
     _display_callbacks = Instance(CallbackDispatcher, ())
     _msg_callbacks = Instance(CallbackDispatcher, ())
     
     #-------------------------------------------------------------------------
     # (Con/de)structor
     #-------------------------------------------------------------------------
     def __init__(self, **kwargs):
         """Public constructor"""
         self._model_id = kwargs.pop('model_id', None)
         super(Widget, self).__init__(**kwargs)
 
         Widget._call_widget_constructed(self)
         self.open()
 
     def __del__(self):
         """Object disposal"""
         self.close()
 
     #-------------------------------------------------------------------------
     # Properties
     #-------------------------------------------------------------------------
 
     def open(self):
         """Open a comm to the frontend if one isn't already open."""
         if self.comm is None:
             args = dict(target_name='ipython.widget',
                         data={'model_name': self._model_name,
                               'model_module': self._model_module})
             if self._model_id is not None:
                 args['comm_id'] = self._model_id
             self.comm = Comm(**args)
 
     def _comm_changed(self, name, new):
         """Called when the comm is changed."""
         if new is None:
             return
         self._model_id = self.model_id
         
         self.comm.on_msg(self._handle_msg)
         Widget.widgets[self.model_id] = self
         
         # first update
         self.send_state()
 
     @property
     def model_id(self):
         """Gets the model id of this widget.
 
         If a Comm doesn't exist yet, a Comm will be created automagically."""
         return self.comm.comm_id
 
     #-------------------------------------------------------------------------
     # Methods
     #-------------------------------------------------------------------------
 
     def close(self):
         """Close method.
 
         Closes the underlying comm.
         When the comm is closed, all of the widget views are automatically
         removed from the front-end."""
         if self.comm is not None:
             Widget.widgets.pop(self.model_id, None)
             self.comm.close()
             self.comm = None
     
     def send_state(self, key=None):
         """Sends the widget state, or a piece of it, to the front-end.
 
         Parameters
         ----------
         key : unicode, or iterable (optional)
             A single property's name or iterable of property names to sync with the front-end.
         """
         state, buffer_keys, buffers = self.get_state(key=key)
         msg = {"method": "update", "state": state}
         if buffer_keys:
             msg['buffers'] = buffer_keys
         self._send(msg, buffers=buffers)
 
     def get_state(self, key=None):
         """Gets the widget state, or a piece of it.
 
         Parameters
         ----------
         key : unicode or iterable (optional)
             A single property's name or iterable of property names to get.
 
         Returns
         -------
         state : dict of states
         buffer_keys : list of strings
             the values that are stored in buffers
         buffers : list of binary memoryviews
             values to transmit in binary
         metadata : dict
             metadata for each field: {key: metadata}
         """
         if key is None:
             keys = self.keys
         elif isinstance(key, string_types):
             keys = [key]
         elif isinstance(key, collections.Iterable):
             keys = key
         else:
             raise ValueError("key must be a string, an iterable of keys, or None")
         state = {}
         buffers = []
         buffer_keys = []
         for k in keys:
             f = self.trait_metadata(k, 'to_json', self._trait_to_json)
             value = getattr(self, k)
             serialized = f(value)
             if isinstance(serialized, memoryview):
                 buffers.append(serialized)
                 buffer_keys.append(k)
             else:
                 state[k] = serialized
         return state, buffer_keys, buffers
 
     def set_state(self, sync_data):
         """Called when a state is received from the front-end."""
         for name in self.keys:
             if name in sync_data:
                 json_value = sync_data[name]
                 from_json = self.trait_metadata(name, 'from_json', self._trait_from_json)
                 with self._lock_property(name, json_value):
                     setattr(self, name, from_json(json_value))
     
     def send(self, content, buffers=None):
         """Sends a custom msg to the widget model in the front-end.
 
         Parameters
         ----------
         content : dict
             Content of the message to send.
         buffers : list of binary buffers
             Binary buffers to send with message
         """
         self._send({"method": "custom", "content": content}, buffers=buffers)
 
     def on_msg(self, callback, remove=False):
         """(Un)Register a custom msg receive callback.
 
         Parameters
         ----------
         callback: callable
             callback will be passed three arguments when a message arrives::
             
                 callback(widget, content, buffers)
             
         remove: bool
             True if the callback should be unregistered."""
         self._msg_callbacks.register_callback(callback, remove=remove)
 
     def on_displayed(self, callback, remove=False):
         """(Un)Register a widget displayed callback.
 
         Parameters
         ----------
         callback: method handler
             Must have a signature of::
             
                 callback(widget, **kwargs)
             
             kwargs from display are passed through without modification.
         remove: bool
             True if the callback should be unregistered."""
         self._display_callbacks.register_callback(callback, remove=remove)
 
     def add_trait(self, traitname, trait):
         """Dynamically add a trait attribute to the Widget."""
         super(Widget, self).add_trait(traitname, trait)
         if trait.get_metadata('sync'):
              self.keys.append(traitname)
              self.send_state(traitname)
 
     #-------------------------------------------------------------------------
     # Support methods
     #-------------------------------------------------------------------------
     @contextmanager
     def _lock_property(self, key, value):
         """Lock a property-value pair.
 
         The value should be the JSON state of the property.
 
         NOTE: This, in addition to the single lock for all state changes, is 
         flawed.  In the future we may want to look into buffering state changes 
         back to the front-end."""
         self._property_lock = (key, value)
         try:
             yield
         finally:
             self._property_lock = (None, None)
 
     @contextmanager
     def hold_sync(self):
         """Hold syncing any state until the context manager is released"""
         # We increment a value so that this can be nested.  Syncing will happen when
         # all levels have been released.
         self._send_state_lock += 1
         try:
             yield
         finally:
             self._send_state_lock -=1
             if self._send_state_lock == 0:
                 self.send_state(self._states_to_send)
                 self._states_to_send.clear()
 
     def _should_send_property(self, key, value):
         """Check the property lock (property_lock)"""
         to_json = self.trait_metadata(key, 'to_json', self._trait_to_json)
         if (key == self._property_lock[0]
             and to_json(value) == self._property_lock[1]):
             return False
         elif self._send_state_lock > 0:
             self._states_to_send.add(key)
             return False
         else:
             return True
     
     # Event handlers
     @_show_traceback
     def _handle_msg(self, msg):
         """Called when a msg is received from the front-end"""
         data = msg['content']['data']
         method = data['method']
 
         # Handle backbone sync methods CREATE, PATCH, and UPDATE all in one.
         if method == 'backbone':
             if 'sync_data' in data:
                 # get binary buffers too
                 sync_data = data['sync_data']
                 for i,k in enumerate(data.get('buffer_keys', [])):
                     sync_data[k] = msg['buffers'][i]
                 self.set_state(sync_data) # handles all methods
 
         # Handle a state request.
         elif method == 'request_state':
             self.send_state()
 
         # Handle a custom msg from the front-end.
         elif method == 'custom':
             if 'content' in data:
                 self._handle_custom_msg(data['content'], msg['buffers'])
 
         # Catch remainder.
         else:
             self.log.error('Unknown front-end to back-end widget msg with method "%s"' % method)
 
     def _handle_custom_msg(self, content, buffers):
         """Called when a custom msg is received."""
         self._msg_callbacks(self, content, buffers)
 
     def _notify_trait(self, name, old_value, new_value):
         """Called when a property has been changed."""
         # Trigger default traitlet callback machinery.  This allows any user
         # registered validation to be processed prior to allowing the widget
         # machinery to handle the state.
         LoggingConfigurable._notify_trait(self, name, old_value, new_value)
 
         # Send the state after the user registered callbacks for trait changes
         # have all fired (allows for user to validate values).
         if self.comm is not None and name in self.keys:
             # Make sure this isn't information that the front-end just sent us.
             if self._should_send_property(name, new_value):
                 # Send new state to front-end
                 self.send_state(key=name)
 
     def _handle_displayed(self, **kwargs):
         """Called when a view has been displayed for this widget instance"""
         self._display_callbacks(self, **kwargs)
 
     def _trait_to_json(self, x):
         """Convert a trait value to json."""
         return x
 
     def _trait_from_json(self, x):
         """Convert json values to objects."""
         return x
 
     def _ipython_display_(self, **kwargs):
         """Called when `IPython.display.display` is called on the widget."""
         # Show view.
         if self._view_name is not None:
             self._send({"method": "display"})
             self._handle_displayed(**kwargs)
 
     def _send(self, msg, buffers=None):
         """Sends a message to the model in the front-end."""
         self.comm.send(data=msg, buffers=buffers)
 
 
 class DOMWidget(Widget):
     visible = Bool(True, allow_none=True, help="Whether the widget is visible.  False collapses the empty space, while None preserves the empty space.", sync=True)
     _css = Tuple(sync=True, help="CSS property list: (selector, key, value)")
     _dom_classes = Tuple(sync=True, help="DOM classes applied to widget.$el.")
     
     width = CUnicode(sync=True)
     height = CUnicode(sync=True)
     # A default padding of 2.5 px makes the widgets look nice when displayed inline.
     padding = CUnicode(sync=True)
     margin = CUnicode(sync=True)
 
     color = Color(None, allow_none=True, sync=True)
     background_color = Color(None, allow_none=True, sync=True)
     border_color = Color(None, allow_none=True, sync=True)
 
     border_width = CUnicode(sync=True)
     border_radius = CUnicode(sync=True)
     border_style = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_border-style.asp
         'none', 
         'hidden', 
         'dotted', 
         'dashed', 
         'solid', 
         'double', 
         'groove', 
         'ridge', 
         'inset', 
         'outset', 
         'initial', 
         'inherit', ''],
         default_value='', sync=True)
 
     font_style = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_font_font-style.asp
         'normal', 
         'italic', 
         'oblique', 
         'initial', 
         'inherit', ''], 
         default_value='', sync=True)
     font_weight = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_font_weight.asp
         'normal', 
         'bold', 
         'bolder', 
         'lighter',
         'initial', 
         'inherit', ''] + list(map(str, range(100,1000,100))),
         default_value='', sync=True)
     font_size = CUnicode(sync=True)
     font_family = Unicode(sync=True)
 
     def __init__(self, *pargs, **kwargs):
         super(DOMWidget, self).__init__(*pargs, **kwargs)
 
         def _validate_border(name, old, new):
             if new is not None and new != '':
                 if name != 'border_width' and not self.border_width:
                     self.border_width = 1
                 if name != 'border_style' and self.border_style == '':
                     self.border_style = 'solid'
         self.on_trait_change(_validate_border, ['border_width', 'border_style', 'border_color'])

IPython/html/widgets/widget_box.py

@@ -1,107 +1,82
 """Box class.  
 
 Represents a container that can be used to group other widgets.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
-from .widget import DOMWidget, Widget, register
+from .widget import DOMWidget, Widget, register, widget_serialization
 from IPython.utils.traitlets import Unicode, Tuple, TraitError, Int, CaselessStrEnum
 from .deprecated import DeprecatedClass
 
-def _widget_to_json(x):
-    if isinstance(x, dict):
-        return {k: _widget_to_json(v) for k, v in x.items()}
-    elif isinstance(x, (list, tuple)):
-        return [_widget_to_json(v) for v in x]
-    elif isinstance(x, Widget):
-        return "IPY_MODEL_" + x.model_id
-    else:
-        return x
-
-def _json_to_widget(x):
-    if isinstance(x, dict):
-        return {k: _json_to_widget(v) for k, v in x.items()}
-    elif isinstance(x, (list, tuple)):
-        return [_json_to_widget(v) for v in x]
-    elif isinstance(x, string_types) and x.startswith('IPY_MODEL_') and x[10:] in Widget.widgets:
-        return Widget.widgets[x[10:]]
-    else:
-        return x
-
-widget_serialization = {
-    'from_json': _json_to_widget,
-    'to_json': _widget_to_json
-}
-
 
 @register('IPython.Box')
 class Box(DOMWidget):
     """Displays multiple widgets in a group."""
     _model_name = Unicode('BoxModel', sync=True)
     _view_name = Unicode('BoxView', sync=True)
 
     # Child widgets in the container.
     # Using a tuple here to force reassignment to update the list.
     # When a proper notifying-list trait exists, that is what should be used here.
     children = Tuple(sync=True, **widget_serialization)
     
     _overflow_values = ['visible', 'hidden', 'scroll', 'auto', 'initial', 'inherit', '']
     overflow_x = CaselessStrEnum(
         values=_overflow_values, 
         default_value='', sync=True, help="""Specifies what
         happens to content that is too large for the rendered region.""")
     overflow_y = CaselessStrEnum(
         values=_overflow_values, 
         default_value='', sync=True, help="""Specifies what
         happens to content that is too large for the rendered region.""")
 
     box_style = CaselessStrEnum(
         values=['success', 'info', 'warning', 'danger', ''], 
         default_value='', allow_none=True, sync=True, help="""Use a
         predefined styling for the box.""")
 
     def __init__(self, children = (), **kwargs):
         kwargs['children'] = children
         super(Box, self).__init__(**kwargs)
         self.on_displayed(Box._fire_children_displayed)
 
     def _fire_children_displayed(self):
         for child in self.children:
             child._handle_displayed()
 
 
 @register('IPython.FlexBox')
 class FlexBox(Box):
     """Displays multiple widgets using the flexible box model."""
     _view_name = Unicode('FlexBoxView', sync=True)
     orientation = CaselessStrEnum(values=['vertical', 'horizontal'], default_value='vertical', sync=True)
     flex = Int(0, sync=True, help="""Specify the flexible-ness of the model.""")
     def _flex_changed(self, name, old, new):
         new = min(max(0, new), 2)
         if self.flex != new:
             self.flex = new
 
     _locations = ['start', 'center', 'end', 'baseline', 'stretch']
     pack = CaselessStrEnum(
         values=_locations, 
         default_value='start', sync=True)
     align = CaselessStrEnum(
         values=_locations, 
         default_value='start', sync=True)
 
 
 def VBox(*pargs, **kwargs):
     """Displays multiple widgets vertically using the flexible box model."""
     kwargs['orientation'] = 'vertical'
     return FlexBox(*pargs, **kwargs)
 
 def HBox(*pargs, **kwargs):
     """Displays multiple widgets horizontally using the flexible box model."""
     kwargs['orientation'] = 'horizontal'
     return FlexBox(*pargs, **kwargs)
 
 
 # Remove in IPython 4.0
 ContainerWidget = DeprecatedClass(Box, 'ContainerWidget')