Allow widget views to be loaded from require modules

This required refactoring things that create widget views to use
callbacks instead of return values.

IPython/html/static/widgets/js/manager.js

@@ -63,15 +63,17 b' define(['
             console.log("Could not determine where the display" + 
                 " message was from.  Widget will not be displayed");
         } else {
-            var view = this.create_view(model, {cell: cell});
-            if (view === null) {
-                console.error("View creation failed", model);
-            }
-            this._handle_display_view(view);
-            if (cell.widget_subarea) {
-                cell.widget_subarea.append(view.$el);
-            }
-            view.trigger('displayed');
+            var that = this;
+            this.create_view(model, {cell: cell, callback: function(view) {
+                if (view === null) {
+                    console.error("View creation failed", model);
+                }
+                that._handle_display_view(view);
+                if (cell.widget_subarea) {
+                    cell.widget_subarea.append(view.$el);
+                }
+                view.trigger('displayed');
+            }});
         }
     };
 
@@ -89,28 +91,38 b' define(['
         } 
         }
     };
+    
 
     WidgetManager.prototype.create_view = function(model, options, view) {
         // Creates a view for a particular model.
-        var view_name = model.get('_view_name');
-        var ViewType = WidgetManager._view_types[view_name];
-        if (ViewType) {
-
-            // If a view is passed into the method, use that view's cell as
-            // the cell for the view that is created.
-            options = options || {};
-            if (view !== undefined) {
-                options.cell = view.options.cell;
+        var instantiate_view = function(ViewType) {
+            if (ViewType) {
+                // If a view is passed into the method, use that view's cell as
+                // the cell for the view that is created.
+                options = options || {};
+                if (view !== undefined) {
+                    options.cell = view.options.cell;
+                }
+
+                // Create and render the view...
+                var parameters = {model: model, options: options};
+                view = new ViewType(parameters);
+                view.render();
+                model.on('destroy', view.remove, view);
+                options.callback(view);
             }
-
-            // Create and render the view...
-            var parameters = {model: model, options: options};
-            view = new ViewType(parameters);
-            view.render();
-            model.on('destroy', view.remove, view);
-            return view;
         }
-        return null;
+        
+        var view_name = model.get('_view_name');
+        var view_mod = model.get('_view_module');
+        if (view_mod !== '') {
+            console.log(view_mod);
+            require([view_mod], function(module) {
+                instantiate_view(module[view_name])
+            });
+        } else {
+            instantiate_view(WidgetManager._view_types[view_name]);
+        }
     };
 
     WidgetManager.prototype.get_msg_cell = function (msg_id) {

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

@@ -308,7 +308,7 b' define(["widgets/js/manager",'
             // Update view to be consistent with this.model
         },
 
-        create_child_view: function(child_model, options) {
+        create_child_view: function(child_model, callback, options) {
             // Create and return a child view.
             //
             // -given a model and (optionally) a view name if the view name is 
@@ -317,18 +317,20 b' define(["widgets/js/manager",'
             // TODO: this is hacky, and makes the view depend on this cell attribute and widget manager behavior
             // it would be great to have the widget manager add the cell metadata
             // to the subview without having to add it here.
-            options = $.extend({ parent: this }, options || {});
-            var child_view = this.model.widget_manager.create_view(child_model, options, this);
-            
-            // Associate the view id with the model id.
-            if (this.child_model_views[child_model.id] === undefined) {
-                this.child_model_views[child_model.id] = [];
-            }
-            this.child_model_views[child_model.id].push(child_view.id);
+            var that = this;
+            options = $.extend({ parent: this, callback: function(child_view) {
+                // Associate the view id with the model id.
+                if (that.child_model_views[child_model.id] === undefined) {
+                    that.child_model_views[child_model.id] = [];
+                }
+                that.child_model_views[child_model.id].push(child_view.id);
 
-            // Remember the view by id.
-            this.child_views[child_view.id] = child_view;
-            return child_view;
+                // Remember the view by id.
+                that.child_views[child_view.id] = child_view;
+                callback(child_view);
+             }}, options || {});
+            
+            this.model.widget_manager.create_view(child_model, options, this);
         },
 
         pop_child_view: function(child_model) {

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

@@ -74,12 +74,14 b' define(['
 
         add_child_model: function(model) {
             // Called when a model is added to the children list.
-            var view = this.create_child_view(model);
-            this.$box.append(view.$el);
+            var that = this;
+            this.create_child_view(model, function(view) {
+                that.$box.append(view.$el);
 
-            // Trigger the displayed event of the child view.
-            this.after_displayed(function() {
-                view.trigger('displayed');
+                // Trigger the displayed event of the child view.
+                that.after_displayed(function() {
+                    view.trigger('displayed');
+                });
             });
         },
     });

IPython/html/static/widgets/js/widget_selectioncontainer.js

@@ -81,7 +81,6 b' define(['
 
         add_child_model: function(model) {
             // Called when a child is added to children list.
-            var view = this.create_child_view(model);
             var index = this.containers.length;
             var uuid = utils.uuid();
             var accordion_group = $('<div />')
@@ -114,14 +113,17 b' define(['
             var container_index = this.containers.push(accordion_group) - 1;
             accordion_group.container_index = container_index;
             this.model_containers[model.id] = accordion_group;
-            accordion_inner.append(view.$el);
+            
+            this.create_child_view(model, function(view) {
+                accordion_inner.append(view.$el);
 
-            this.update();
-            this.update_titles();
+                that.update();
+                that.update_titles();
 
-            // Trigger the displayed event of the child view.
-            this.after_displayed(function() {
-                view.trigger('displayed');
+                // Trigger the displayed event of the child view.
+                that.after_displayed(function() {
+                    view.trigger('displayed');
+                });
             });
         },
     });
@@ -176,7 +178,6 b' define(['
 
         add_child_model: function(model) {
             // Called when a child is added to children list.
-            var view = this.create_child_view(model);
             var index = this.containers.length;
             var uuid = utils.uuid();
 
@@ -184,33 +185,36 b' define(['
             var tab = $('<li />')
                 .css('list-style-type', 'none')
                 .appendTo(this.$tabs);
-            view.parent_tab = tab;
-
-            var tab_text = $('<a />')
-                .attr('href', '#' + uuid)
-                .attr('data-toggle', 'tab') 
-                .text('Page ' + index)
-                .appendTo(tab)
-                .click(function (e) {
             
-                    // Calling model.set will trigger all of the other views of the 
-                    // model to update.
-                    that.model.set("selected_index", index, {updated_view: this});
-                    that.touch();
-                    that.select_page(index);
+            this.create_child_view(model, function(view) {
+                view.parent_tab = tab;
+
+                var tab_text = $('<a />')
+                    .attr('href', '#' + uuid)
+                    .attr('data-toggle', 'tab') 
+                    .text('Page ' + index)
+                    .appendTo(tab)
+                    .click(function (e) {
+                
+                        // Calling model.set will trigger all of the other views of the 
+                        // model to update.
+                        that.model.set("selected_index", index, {updated_view: that});
+                        that.touch();
+                        that.select_page(index);
+                    });
+                tab.tab_text_index = that.containers.push(tab_text) - 1;
+
+                var contents_div = $('<div />', {id: uuid})
+                    .addClass('tab-pane')
+                    .addClass('fade')
+                    .append(view.$el)
+                    .appendTo(that.$tab_contents);
+                view.parent_container = contents_div;
+
+                // Trigger the displayed event of the child view.
+                that.after_displayed(function() {
+                    view.trigger('displayed');
                 });
-            tab.tab_text_index = this.containers.push(tab_text) - 1;
-
-            var contents_div = $('<div />', {id: uuid})
-                .addClass('tab-pane')
-                .addClass('fade')
-                .append(view.$el)
-                .appendTo(this.$tab_contents);
-            view.parent_container = contents_div;
-
-            // Trigger the displayed event of the child view.
-            this.after_displayed(function() {
-                view.trigger('displayed');
             });
         },
 

IPython/html/widgets/widget.py

@@ -100,6 +100,8 b' class Widget(LoggingConfigurable):'
     #-------------------------------------------------------------------------
     _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')