First attempt at multi-cell selection

It works, but I'm not quite happy with how it works

notebook/static/notebook/js/actions.js

@@ -100,6 +100,28 @@ define(function(require){
                 }
             }
         },
+        'extend-selection-previous' : {
+            help: 'extend selection above',
+            help_index : 'dc',
+            handler : function (env) {
+                var index = env.notebook.get_selected_index();
+                if (index !== (env.notebook.ncells()-1) && index !== null) {
+                    env.notebook.select_prev(true);
+                    env.notebook.focus_cell();
+                }
+            }
+        },
+        'extend-selection-next' : {
+            help: 'extend selection below',
+            help_index : 'dd',
+            handler : function (env) {
+                var index = env.notebook.get_selected_index();
+                if (index !== (env.notebook.ncells()-1) && index !== null) {
+                    env.notebook.select_next(true);
+                    env.notebook.focus_cell();
+                }
+            }
+        },
         'cut-selected-cell' : {
             icon: 'fa-cut',
             help_index : 'ee',

notebook/static/notebook/js/cell.js

@@ -55,6 +55,7 @@ define([
         
         this.placeholder = config.placeholder || '';
         this.selected = false;
+        this.in_selection = false;
         this.rendered = false;
         this.mode = 'command';
 
@@ -142,7 +143,7 @@ define([
          * Call after this.element exists to initialize the css classes
          * related to selected, rendered and mode.
          */
-        if (this.selected) {
+        if (this.in_selection) {
             this.element.addClass('selected');
         } else {
             this.element.addClass('unselected');
@@ -254,6 +255,7 @@ define([
             this.element.addClass('selected');
             this.element.removeClass('unselected');
             this.selected = true;
+            this.in_selection = true;
             return true;
         } else {
             return false;
@@ -261,19 +263,20 @@ define([
     };
 
     /**
-     * handle cell level logic when a cell is unselected
+     * handle cell level logic when the cursor moves away from a cell
      * @method unselect
+     * @param {bool} leave_selected - true to move cursor away and extend selection
      * @return is the action being taken
      */
-    Cell.prototype.unselect = function () {
-        if (this.selected) {
+    Cell.prototype.unselect = function (leave_selected) {
+        var was_selected_cell = this.selected;
+        this.selected = false;
+        if ((!leave_selected) && this.in_selection) {
+            this.in_selection = false;
             this.element.addClass('unselected');
             this.element.removeClass('selected');
-            this.selected = false;
-            return true;
-        } else {
-            return false;
         }
+        return was_selected_cell;
     };
 
     /**

notebook/static/notebook/js/codecell.js

@@ -535,14 +535,14 @@ define([
     };
 
     /**
-     * handle cell level logic when a cell is unselected
+     * handle cell level logic when the cursor moves away from a cell
      * @method unselect
      * @return is the action being taken
      */
-    CodeCell.prototype.unselect = function () {
-        var cont = Cell.prototype.unselect.apply(this);
+    CodeCell.prototype.unselect = function (leave_selected) {
+        var cont = Cell.prototype.unselect.apply(this, [leave_selected]);
         if (cont) {
-            // When a code cell is usnelected, make sure that the corresponding
+            // When a code cell is unselected, make sure that the corresponding
             // tooltip and completer to that cell is closed.
             this.tooltip.remove_and_cancel_tooltip(true);
             if (this.completer !== null) {

notebook/static/notebook/js/keyboardmanager.js

@@ -98,6 +98,8 @@ define([
             'up' : 'ipython.select-previous-cell',
             'k' : 'ipython.select-previous-cell',
             'j' : 'ipython.select-next-cell',
+            'shift-k': 'ipython.extend-selection-previous',
+            'shift-j': 'ipython.extend-selection-next',
             'x' : 'ipython.cut-selected-cell',
             'c' : 'ipython.copy-selected-cell',
             'v' : 'ipython.paste-cell-after',

notebook/static/notebook/js/notebook.js

@@ -600,6 +600,17 @@ define(function (require) {
         return result;
     };
 
+    /**
+     * Get an array of the cells in the currently selected range
+     *
+     * @return {Array} The selected cells
+     */
+    Notebook.prototype.get_selected_cells = function () {
+        return this.get_cells().filter(function(cell) {
+            return cell.in_selection;
+        });
+    };
+
 
     // Cell selection.
 
@@ -607,9 +618,10 @@ define(function (require) {
      * Programmatically select a cell.
      * 
      * @param {integer} index - A cell's index
+     * @param {bool} add_to_selection - whether to add to the current selection
      * @return {Notebook} This notebook
      */
-    Notebook.prototype.select = function (index) {
+    Notebook.prototype.select = function (index, add_to_selection) {
         if (this.is_valid_cell_index(index)) {
             var sindex = this.get_selected_index();
             if (sindex !== null && index !== sindex) {
@@ -618,8 +630,12 @@ define(function (require) {
                 if (this.mode !== 'command') {
                     this.command_mode();
                 }
-                this.get_cell(sindex).unselect();
             }
+            var current_selection = this.get_selected_cells();
+            for (var i=0; i<current_selection.length; i++) {
+                current_selection[i].unselect(add_to_selection)
+            }
+
             var cell = this.get_cell(index);
             cell.select();
             if (cell.cell_type === 'heading') {
@@ -638,22 +654,40 @@ define(function (require) {
     /**
      * Programmatically select the next cell.
      *
+     * @param {bool} extend_selection - whether to add to the current selection
      * @return {Notebook} This notebook
      */
-    Notebook.prototype.select_next = function () {
+    Notebook.prototype.select_next = function (extend_selection) {
         var index = this.get_selected_index();
-        this.select(index+1);
+        // XXX: If we're extending the range selection to an already-selected
+        // cell, the cursor is moving back into the selected range, and we
+        // actually want to contract the selection by unselecting the cell at
+        // the previous cursor position. Not entirely happy with this, but it's
+        // the best idea I have for now.
+        if (extend_selection && this.get_cell(index+1).in_selection) {
+            this.get_cell(index).unselect();
+        }
+        this.select(index+1, extend_selection);
         return this;
     };
 
     /**
      * Programmatically select the previous cell.
      *
+     * @param {bool} extend_selection - whether to add to the current selection
      * @return {Notebook} This notebook
      */
-    Notebook.prototype.select_prev = function () {
+    Notebook.prototype.select_prev = function (extend_selection) {
         var index = this.get_selected_index();
-        this.select(index-1);
+        // XXX: If we're extending the range selection to an already-selected
+        // cell, the cursor is moving back into the selected range, and we
+        // actually want to contract the selection by unselecting the cell at
+        // the previous cursor position. Not entirely happy with this, but it's
+        // the best idea I have for now.
+        if (extend_selection && this.get_cell(index-1).in_selection) {
+            this.get_cell(index).unselect();
+        }
+        this.select(index-1, extend_selection);
         return this;
     };