Pager is not activated if the pager text is empty.

* Things like asdf.*? used to open the pager even though there
  was nothing to show.

IPython/frontend/html/notebook/static/js/notebook.js

@@ -1,813 +1,815 b''
 
 //============================================================================
 // Notebook
 //============================================================================
 
 var IPython = (function (IPython) {
 
     var utils = IPython.utils;
 
     var Notebook = function (selector) {
         this.element = $(selector);
         this.element.scroll();
         this.element.data("notebook", this);
         this.next_prompt_number = 1;
         this.kernel = null;
         this.dirty = false;
         this.msg_cell_map = {};
         this.style();
         this.create_elements();
         this.bind_events();
     };
 
 
     Notebook.prototype.style = function () {
         $('div#notebook').addClass('border-box-sizing');
     };
 
 
     Notebook.prototype.create_elements = function () {
         // We add this end_space div to the end of the notebook div to:
         // i) provide a margin between the last cell and the end of the notebook
         // ii) to prevent the div from scrolling up when the last cell is being
         // edited, but is too low on the page, which browsers will do automatically.
         this.element.append($('<div class="end_space"></div>').height(150));
         $('div#notebook').addClass('border-box-sizing');
     };
 
 
     Notebook.prototype.bind_events = function () {
         var that = this;
         $(document).keydown(function (event) {
             // console.log(event);
             if (event.which === 38) {
                 var cell = that.selected_cell();
                 if (cell.at_top()) {
                     event.preventDefault();
                     that.select_prev();
                 };
             } else if (event.which === 40) {
                 var cell = that.selected_cell();
                 if (cell.at_bottom()) {
                     event.preventDefault();
                     that.select_next();
                 };
             } else if (event.which === 13 && event.shiftKey) {
                 that.execute_selected_cell();
                 return false;
             } else if (event.which === 13 && event.ctrlKey) {
                 that.execute_selected_cell({terminal:true});
                 return false;
             };
         });
 
         this.element.bind('collapse_pager', function () {
             var app_height = $('div#main_app').height(); // content height
             var splitter_height = $('div#pager_splitter').outerHeight(true);
             var new_height = app_height - splitter_height;
             that.element.animate({height : new_height + 'px'}, 'fast');
         });
 
         this.element.bind('expand_pager', function () {
             var app_height = $('div#main_app').height(); // content height
             var splitter_height = $('div#pager_splitter').outerHeight(true);
             var pager_height = $('div#pager').outerHeight(true);
             var new_height = app_height - pager_height - splitter_height; 
             that.element.animate({height : new_height + 'px'}, 'fast');
         });
 
         this.element.bind('collapse_left_panel', function () {
             var splitter_width = $('div#left_panel_splitter').outerWidth(true);
             var new_margin = splitter_width;
             $('div#notebook_panel').animate({marginLeft : new_margin + 'px'}, 'fast');
         });
 
         this.element.bind('expand_left_panel', function () {
             var splitter_width = $('div#left_panel_splitter').outerWidth(true);
             var left_panel_width = IPython.left_panel.width;
             var new_margin = splitter_width + left_panel_width;
             $('div#notebook_panel').animate({marginLeft : new_margin + 'px'}, 'fast');
         });
 
         $(window).bind('beforeunload', function () {
             var kill_kernel = $('#kill_kernel').prop('checked');                
             if (kill_kernel) {
                 that.kernel.kill();
             }
             if (that.dirty) {
                 return "You have unsaved changes that will be lost if you leave this page.";
             };
         });
     };
 
 
     Notebook.prototype.scroll_to_bottom = function () {
         this.element.animate({scrollTop:this.element.get(0).scrollHeight}, 0);
     };
 
 
     Notebook.prototype.scroll_to_top = function () {
         this.element.animate({scrollTop:0}, 0);
     };
 
 
     // Cell indexing, retrieval, etc.
 
 
     Notebook.prototype.cell_elements = function () {
         return this.element.children("div.cell");
     }
 
 
     Notebook.prototype.ncells = function (cell) {
         return this.cell_elements().length;
     }
 
 
     // TODO: we are often calling cells as cells()[i], which we should optimize
     // to cells(i) or a new method.
     Notebook.prototype.cells = function () {
         return this.cell_elements().toArray().map(function (e) {
             return $(e).data("cell");
         });
     }
 
 
     Notebook.prototype.find_cell_index = function (cell) {
         var result = null;
         this.cell_elements().filter(function (index) {
             if ($(this).data("cell") === cell) {
                 result = index;
             };
         });
         return result;
     };
 
 
     Notebook.prototype.index_or_selected = function (index) {
         return index || this.selected_index() || 0;
     }
 
 
     Notebook.prototype.select = function (index) {
         if (index !== undefined && index >= 0 && index < this.ncells()) {
             if (this.selected_index() !== null) {
                 this.selected_cell().unselect();
             };
             this.cells()[index].select();
             if (index === (this.ncells()-1)) {
                 this.scroll_to_bottom();
             };
         };
         return this;
     };
 
 
     Notebook.prototype.select_next = function () {
         var index = this.selected_index();
         if (index !== null && index >= 0 && (index+1) < this.ncells()) {
             this.select(index+1);
         };
         return this;
     };
 
 
     Notebook.prototype.select_prev = function () {
         var index = this.selected_index();
         if (index !== null && index >= 0 && (index-1) < this.ncells()) {
             this.select(index-1);
         };
         return this;
     };
 
 
     Notebook.prototype.selected_index = function () {
         var result = null;
         this.cell_elements().filter(function (index) {
             if ($(this).data("cell").selected === true) {
                 result = index;
             };
         });
         return result;
     };
 
 
     Notebook.prototype.cell_for_msg = function (msg_id) {
         var cell_id = this.msg_cell_map[msg_id];
         var result = null;
         this.cell_elements().filter(function (index) {
             cell = $(this).data("cell");
             if (cell.cell_id === cell_id) {
                 result = cell;
             };
         });
         return result;
     };
 
 
     Notebook.prototype.selected_cell = function () {
         return this.cell_elements().eq(this.selected_index()).data("cell");
     }
 
 
     // Cell insertion, deletion and moving.
 
 
     Notebook.prototype.delete_cell = function (index) {
         var i = index || this.selected_index();
         if (i !== null && i >= 0 && i < this.ncells()) {
             this.cell_elements().eq(i).remove();
             if (i === (this.ncells())) {
                 this.select(i-1);
             } else {
                 this.select(i);
             };
         };
         this.dirty = true;
         return this;
     };
 
 
     Notebook.prototype.append_cell = function (cell) {
         this.element.find('div.end_space').before(cell.element);
         this.dirty = true;
         return this;
     };
 
 
     Notebook.prototype.insert_cell_after = function (cell, index) {
         var ncells = this.ncells();
         if (ncells === 0) {
             this.append_cell(cell);
             return this;
         };
         if (index >= 0 && index < ncells) {
             this.cell_elements().eq(index).after(cell.element);
         };
         this.dirty = true;
         return this
     };
 
 
     Notebook.prototype.insert_cell_before = function (cell, index) {
         var ncells = this.ncells();
         if (ncells === 0) {
             this.append_cell(cell);
             return this;
         };
         if (index >= 0 && index < ncells) {
             this.cell_elements().eq(index).before(cell.element);
         };
         this.dirty = true;
         return this;
     };
 
 
     Notebook.prototype.move_cell_up = function (index) {
         var i = index || this.selected_index();
         if (i !== null && i < this.ncells() && i > 0) {
             var pivot = this.cell_elements().eq(i-1);
             var tomove = this.cell_elements().eq(i);
             if (pivot !== null && tomove !== null) {
                 tomove.detach();
                 pivot.before(tomove);
                 this.select(i-1);
             };
         };
         this.dirty = true;
         return this;
     }
 
 
     Notebook.prototype.move_cell_down = function (index) {
         var i = index || this.selected_index();
         if (i !== null && i < (this.ncells()-1) && i >= 0) {
             var pivot = this.cell_elements().eq(i+1)
             var tomove = this.cell_elements().eq(i)
             if (pivot !== null && tomove !== null) {
                 tomove.detach();
                 pivot.after(tomove);
                 this.select(i+1);
             };
         };
         this.dirty = true;
         return this;
     }
 
 
     Notebook.prototype.sort_cells = function () {
         var ncells = this.ncells();
         var sindex = this.selected_index();
         var swapped;
         do {
             swapped = false
             for (var i=1; i<ncells; i++) {
                 current = this.cell_elements().eq(i).data("cell");
                 previous = this.cell_elements().eq(i-1).data("cell");
                 if (previous.input_prompt_number > current.input_prompt_number) {
                     this.move_cell_up(i);
                     swapped = true;
                 };
             };
         } while (swapped);
         this.select(sindex);
         return this;
     };
 
 
     Notebook.prototype.insert_code_cell_before = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var cell = new IPython.CodeCell(this);
         cell.set_input_prompt();
         this.insert_cell_before(cell, i);
         this.select(this.find_cell_index(cell));
         return cell;
     }
 
 
     Notebook.prototype.insert_code_cell_after = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var cell = new IPython.CodeCell(this);
         cell.set_input_prompt();
         this.insert_cell_after(cell, i);
         this.select(this.find_cell_index(cell));
         return cell;
     }
 
 
     Notebook.prototype.insert_html_cell_before = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var cell = new IPython.HTMLCell(this);
         cell.config_mathjax();
         this.insert_cell_before(cell, i);
         this.select(this.find_cell_index(cell));
         return cell;
     }
 
 
     Notebook.prototype.insert_html_cell_after = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var cell = new IPython.HTMLCell(this);
         cell.config_mathjax();
         this.insert_cell_after(cell, i);
         this.select(this.find_cell_index(cell));
         return cell;
     }
 
 
     Notebook.prototype.insert_markdown_cell_before = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var cell = new IPython.MarkdownCell(this);
         cell.config_mathjax();
         this.insert_cell_before(cell, i);
         this.select(this.find_cell_index(cell));
         return cell;
     }
 
 
     Notebook.prototype.insert_markdown_cell_after = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var cell = new IPython.MarkdownCell(this);
         cell.config_mathjax();
         this.insert_cell_after(cell, i);
         this.select(this.find_cell_index(cell));
         return cell;
     }
 
 
     Notebook.prototype.to_code = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var source_element = this.cell_elements().eq(i);
         var source_cell = source_element.data("cell");
         if (source_cell instanceof IPython.HTMLCell || 
             source_cell instanceof IPython.MarkdownCell) {
             this.insert_code_cell_after(i);
             var target_cell = this.cells()[i+1];
             target_cell.set_code(source_cell.get_source());
             source_element.remove();
             target_cell.select();
         };
         this.dirty = true;
     };
 
 
     Notebook.prototype.to_markdown = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var source_element = this.cell_elements().eq(i);
         var source_cell = source_element.data("cell");
         var target_cell = null;
         if (source_cell instanceof IPython.CodeCell) {
             this.insert_markdown_cell_after(i);
             var target_cell = this.cells()[i+1];
             var text = source_cell.get_code();
         } else if (source_cell instanceof IPython.HTMLCell) {
             this.insert_markdown_cell_after(i);
             var target_cell = this.cells()[i+1];
             var text = source_cell.get_source();
             if (text === source_cell.placeholder) {
                 text = target_cell.placeholder;
             }
         }
         if (target_cell !== null) {
             if (text === "") {text = target_cell.placeholder;};
             target_cell.set_source(text);
             source_element.remove();
             target_cell.edit();
         }
         this.dirty = true;
     };
 
 
     Notebook.prototype.to_html = function (index) {
         // TODO: Bounds check for i
         var i = this.index_or_selected(index);
         var source_element = this.cell_elements().eq(i);
         var source_cell = source_element.data("cell");
         var target_cell = null;
         if (source_cell instanceof IPython.CodeCell) {
             this.insert_html_cell_after(i);
             var target_cell = this.cells()[i+1];
             var text = source_cell.get_code();
         } else if (source_cell instanceof IPython.MarkdownCell) {
             this.insert_html_cell_after(i);
             var target_cell = this.cells()[i+1];
             var text = source_cell.get_source();
             if (text === source_cell.placeholder) {
                 text = target_cell.placeholder;
             }
         }
         if (target_cell !== null) {
             if (text === "") {text = target_cell.placeholder;};
             target_cell.set_source(text);
             source_element.remove();
             target_cell.edit();
         }
         this.dirty = true;
     };
 
 
     // Cell collapsing and output clearing
 
     Notebook.prototype.collapse = function (index) {
         var i = this.index_or_selected(index);
         this.cells()[i].collapse();
         this.dirty = true;
     };
 
 
     Notebook.prototype.expand = function (index) {
         var i = this.index_or_selected(index);
         this.cells()[i].expand();
         this.dirty = true;
     };
 
 
     Notebook.prototype.set_autoindent = function (state) {
         var cells = this.cells();
         len = cells.length;
         for (var i=0; i<len; i++) {
             cells[i].set_autoindent(state)
         };
     };
 
 
     Notebook.prototype.clear_all_output = function () {
         var ncells = this.ncells();
         var cells = this.cells();
         for (var i=0; i<ncells; i++) {
             if (cells[i] instanceof IPython.CodeCell) {
                 cells[i].clear_output();
             }
         };
         this.dirty = true;
     };
 
 
     // Kernel related things
 
     Notebook.prototype.start_kernel = function () {
         this.kernel = new IPython.Kernel();
         var notebook_id = IPython.save_widget.get_notebook_id();
         this.kernel.start(notebook_id, $.proxy(this.kernel_started, this));
     };
 
 
     Notebook.prototype.restart_kernel = function () {
         var notebook_id = IPython.save_widget.get_notebook_id();
         this.kernel.restart($.proxy(this.kernel_started, this));
     };
 
 
     Notebook.prototype.kernel_started = function () {
         console.log("Kernel started: ", this.kernel.kernel_id);
         this.kernel.shell_channel.onmessage = $.proxy(this.handle_shell_reply,this);
         this.kernel.iopub_channel.onmessage = $.proxy(this.handle_iopub_reply,this);
     };
 
 
     Notebook.prototype.handle_shell_reply = function (e) {
         reply = $.parseJSON(e.data);
         var header = reply.header;
         var content = reply.content;
         var msg_type = header.msg_type;
         // console.log(reply);
         var cell = this.cell_for_msg(reply.parent_header.msg_id);
         if (msg_type === "execute_reply") {
             cell.set_input_prompt(content.execution_count);
             this.dirty = true;
         } else if (msg_type === "complete_reply") {
             cell.finish_completing(content.matched_text, content.matches);
         };
         var payload = content.payload || [];
         this.handle_payload(cell, payload);
     };
 
 
     Notebook.prototype.handle_payload = function (cell, payload) {
         var l = payload.length;
         for (var i=0; i<l; i++) {
             if (payload[i].source === 'IPython.zmq.page.page') {
-                IPython.pager.clear();
-                IPython.pager.expand();
-                IPython.pager.append_text(payload[i].text);
+                if (payload[i].text.trim() !== '') {
+                    IPython.pager.clear();
+                    IPython.pager.expand();
+                    IPython.pager.append_text(payload[i].text);
+                }
             } else if (payload[i].source === 'IPython.zmq.zmqshell.ZMQInteractiveShell.set_next_input') {
                 var index = this.find_cell_index(cell);
                 var new_cell = this.insert_code_cell_after(index);
                 new_cell.set_code(payload[i].text);
                 this.dirty = true;
             }
         };
     };
 
 
     Notebook.prototype.handle_iopub_reply = function (e) {
         reply = $.parseJSON(e.data);
         var content = reply.content;
         // console.log(reply);
         var msg_type = reply.header.msg_type;
         var cell = this.cell_for_msg(reply.parent_header.msg_id);
         var output_types = ['stream','display_data','pyout','pyerr'];
         if (output_types.indexOf(msg_type) >= 0) {
             this.handle_output(cell, msg_type, content);
         } else if (msg_type === 'status') {
             if (content.execution_state === 'busy') {
                 IPython.kernel_status_widget.status_busy();
             } else if (content.execution_state === 'idle') {
                 IPython.kernel_status_widget.status_idle();
             } else if (content.execution_state === 'dead') {
                 this.handle_status_dead();
             };
         }
     };
 
 
     Notebook.prototype.handle_status_dead = function () {
         var that = this;
         this.kernel.stop_channels();
         var dialog = $('<div/>');
         dialog.html('The kernel has died, would you like to restart it? If you do not restart the kernel, you will be able to save the notebook, but running code will not work until the notebook is reopened.');
         $(document).append(dialog);
         dialog.dialog({
             resizable: false,
             modal: true,
             title: "Dead kernel",
             buttons : {
                 "Yes": function () {
                     that.start_kernel();
                     $(this).dialog('close');
                 },
                 "No": function () {
                     $(this).dialog('close');
                 }
             }
         });
     };
 
 
     Notebook.prototype.handle_output = function (cell, msg_type, content) {
         var json = {};
         json.output_type = msg_type;
         if (msg_type === "stream") {
             json.text = utils.fixConsole(content.data + '\n');
         } else if (msg_type === "display_data") {
             json = this.convert_mime_types(json, content.data);
         } else if (msg_type === "pyout") {
             json.prompt_number = content.execution_count;
             json = this.convert_mime_types(json, content.data);
         } else if (msg_type === "pyerr") {
             json.ename = content.ename;
             json.evalue = content.evalue;
             var traceback = [];
             for (var i=0; i<content.traceback.length; i++) {
                 traceback.push(utils.fixConsole(content.traceback[i]));
             }
             json.traceback = traceback;
         };
         cell.append_output(json);
         this.dirty = true;
     };
 
 
     Notebook.prototype.convert_mime_types = function (json, data) {
         if (data['text/plain'] !== undefined) {
             json.text = utils.fixConsole(data['text/plain']);
         };
         if (data['text/html'] !== undefined) {
             json.html = data['text/html'];
         };
         if (data['image/svg+xml'] !== undefined) {
             json.svg = data['image/svg+xml'];
         };
         if (data['image/png'] !== undefined) {
             json.png = data['image/png'];
         };
         if (data['image/jpeg'] !== undefined) {
             json.jpeg = data['image/jpeg'];
         };
         if (data['text/latex'] !== undefined) {
             json.latex = data['text/latex'];
         };
         if (data['application/json'] !== undefined) {
             json.json = data['application/json'];
         };
         if (data['application/javascript'] !== undefined) {
             json.javascript = data['application/javascript'];
         }
         return json;    
     };
 
 
     Notebook.prototype.execute_selected_cell = function (options) {
         // add_new: should a new cell be added if we are at the end of the nb
         // terminal: execute in terminal mode, which stays in the current cell
         default_options = {terminal: false, add_new: true}
         $.extend(default_options, options)
         var that = this;
         var cell = that.selected_cell();
         var cell_index = that.find_cell_index(cell);
         if (cell instanceof IPython.CodeCell) {
             cell.clear_output();
             var code = cell.get_code();
             var msg_id = that.kernel.execute(cell.get_code());
             that.msg_cell_map[msg_id] = cell.cell_id;
         } else if (cell instanceof IPython.HTMLCell) {
             cell.render();
         }
         if (default_options.terminal) {
             cell.clear_input();
         } else {
             if ((cell_index === (that.ncells()-1)) && default_options.add_new) {
                 that.insert_code_cell_after();
                 // If we are adding a new cell at the end, scroll down to show it.
                 that.scroll_to_bottom();
             } else {
                 that.select(cell_index+1);
             };
         };
         this.dirty = true;
     };
 
 
     Notebook.prototype.execute_all_cells = function () {
         var ncells = this.ncells();
         for (var i=0; i<ncells; i++) {
             this.select(i);
             this.execute_selected_cell({add_new:false});
         };
         this.scroll_to_bottom();
     };
 
 
     Notebook.prototype.complete_cell = function (cell, line, cursor_pos) {
         var msg_id = this.kernel.complete(line, cursor_pos);
         this.msg_cell_map[msg_id] = cell.cell_id;
     };
 
     // Persistance and loading
 
 
     Notebook.prototype.fromJSON = function (data) {
         var ncells = this.ncells();
         for (var i=0; i<ncells; i++) {
             // Always delete cell 0 as they get renumbered as they are deleted.
             this.delete_cell(0);
         };
         // Only handle 1 worksheet for now.
         var worksheet = data.worksheets[0];
         if (worksheet !== undefined) {
             var new_cells = worksheet.cells;
             ncells = new_cells.length;
             var cell_data = null;
             var new_cell = null;
             for (var i=0; i<ncells; i++) {
                 cell_data = new_cells[i];
                 if (cell_data.cell_type == 'code') {
                     new_cell = this.insert_code_cell_after();
                     new_cell.fromJSON(cell_data);
                 } else if (cell_data.cell_type === 'html') {
                     new_cell = this.insert_html_cell_after();
                     new_cell.fromJSON(cell_data);
                 } else if (cell_data.cell_type === 'markdown') {
                     new_cell = this.insert_markdown_cell_after();
                     new_cell.fromJSON(cell_data);
                 };
             };          
         };
     };
 
 
     Notebook.prototype.toJSON = function () {
         var cells = this.cells();
         var ncells = cells.length;
         cell_array = new Array(ncells);
         for (var i=0; i<ncells; i++) {
             cell_array[i] = cells[i].toJSON();
         };
         data = {
             // Only handle 1 worksheet for now.
             worksheets : [{cells:cell_array}]
         }
         return data
     };
 
     Notebook.prototype.save_notebook = function () {
         if (IPython.save_widget.test_notebook_name()) {
             var notebook_id = IPython.save_widget.get_notebook_id();
             var nbname = IPython.save_widget.get_notebook_name();
             // We may want to move the name/id/nbformat logic inside toJSON?
             var data = this.toJSON();
             data.name = nbname;
             data.nbformat = 2;
             // We do the call with settings so we can set cache to false.
             var settings = {
                 processData : false,
                 cache : false,
                 type : "PUT",
                 data : JSON.stringify(data),
                 headers : {'Content-Type': 'application/json'},
                 success : $.proxy(this.notebook_saved,this)
             };
             IPython.save_widget.status_saving();
             $.ajax("/notebooks/" + notebook_id, settings);
         };
     };
 
 
     Notebook.prototype.notebook_saved = function (data, status, xhr) {
         this.dirty = false;
         setTimeout($.proxy(IPython.save_widget.status_save,IPython.save_widget),500);
     }
 
 
     Notebook.prototype.load_notebook = function (callback) {
         var that = this;
         var notebook_id = IPython.save_widget.get_notebook_id();
         // We do the call with settings so we can set cache to false.
         var settings = {
             processData : false,
             cache : false,
             type : "GET",
             dataType : "json",
             success : function (data, status, xhr) {
                 that.notebook_loaded(data, status, xhr);
                 if (callback !== undefined) {
                     callback();
                 };
             }
         };
         IPython.save_widget.status_loading();
         $.ajax("/notebooks/" + notebook_id, settings);
     }
 
 
     Notebook.prototype.notebook_loaded = function (data, status, xhr) {
         this.fromJSON(data);
         if (this.ncells() === 0) {
             this.insert_code_cell_after();
         };
         IPython.save_widget.status_save();
         IPython.save_widget.set_notebook_name(data.name);
         this.start_kernel();
         this.dirty = false;
         // fromJSON always selects the last cell inserted. We need to wait
         // until that is done before scrolling to the top.
         setTimeout(function () {
             IPython.notebook.select(0);
             IPython.notebook.scroll_to_top();
         }, 50);
     };
 
     IPython.Notebook = Notebook;
 
     return IPython;
 
 }(IPython));