Updating cell logic.

* Added placeholder to the base Cell class.
* Removed the \u0000 char at the beginning of the TextCell
  placeholder that was there for a CodeMirror bug workaround.
* Other refactoring of Cell related Notebook methods.

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

@@ -14,6 +14,7 b' var IPython = (function (IPython) {'
     var utils = IPython.utils;
 
     var Cell = function (notebook) {
+        this.placeholder = this.placeholder || '';
         this.notebook = notebook;
         this.read_only = false;
         if (notebook){

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

@@ -93,6 +93,24 b' var IPython = (function (IPython) {'
             var cursor = editor.getCursor();
             var pre_cursor = editor.getRange({line:cursor.line,ch:0},cursor).trim()+'(';
             that.request_tooltip_after_time(pre_cursor,tooltip_wait_time);
+        } else if (event.which === 38) {
+            // If we are not at the top, let CM handle the up arrow and
+            // prevent the global keydown handler from handling it.
+            if (!that.at_top()) {
+                event.stop();
+                return false;
+            } else {
+                return true; 
+            };
+        } else if (event.which === 40) {
+            // If we are not at the bottom, let CM handle the down arrow and
+            // prevent the global keydown handler from handling it.
+            if (!that.at_bottom()) {
+                event.stop();
+                return false;
+            } else {
+                return true; 
+            };
         } else if (event.keyCode === 9 && event.type == 'keydown') {
             // Tab completion.
             var cur = editor.getCursor();

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

@@ -512,8 +512,7 b' var IPython = (function (IPython) {'
         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) {
+        if (!(source_cell instanceof IPython.CodeCell)) {
             this.insert_code_cell_below(i);
             var target_cell = this.cells()[i+1];
             var text = source_cell.get_text();
@@ -534,27 +533,23 b' var IPython = (function (IPython) {'
         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_below(i);
-            target_cell = this.cells()[i+1];
-            var text = source_cell.get_text();
-        } else if (source_cell instanceof IPython.HTMLCell) {
+        if (!(source_cell instanceof IPython.MarkdownCell)) {
             this.insert_markdown_cell_below(i);
             target_cell = this.cells()[i+1];
             var text = source_cell.get_text();
             if (text === source_cell.placeholder) {
                 text = target_cell.placeholder;
+            };
+            if (target_cell !== null) {
+                if (text === "") {text = target_cell.placeholder;};
+                // The edit must come before the set_text.
+                target_cell.edit();
+                target_cell.set_text(text);
+                source_element.remove();
+                target_cell.select();
             }
-        }
-        if (target_cell !== null) {
-            if (text === "") {text = target_cell.placeholder;};
-            // The edit must come before the set_text.
-            target_cell.edit();
-            target_cell.set_text(text);
-            source_element.remove();
-            target_cell.select();
-        }
-        this.dirty = true;
+            this.dirty = true;
+        };
     };
 
 
@@ -564,25 +559,23 b' var IPython = (function (IPython) {'
         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_below(i);
-            target_cell = this.cells()[i+1];
-            var text = source_cell.get_text();
-        } else if (source_cell instanceof IPython.MarkdownCell) {
+        if (!(source_cell instanceof IPython.HTMLCell)) {
             this.insert_html_cell_below(i);
             target_cell = this.cells()[i+1];
             var text = source_cell.get_text();
             if (text === source_cell.placeholder) {
                 text = target_cell.placeholder;
+            };
+            if (target_cell !== null) {
+                if (text === "") {text = target_cell.placeholder;};
+                // The edit must come before the set_text.
+                target_cell.edit();
+                target_cell.set_text(text);
+                source_element.remove();
+                target_cell.select();
             }
-        }
-        if (target_cell !== null) {
-            if (text === "") {text = target_cell.placeholder;};
-            target_cell.set_text(text);
-            source_element.remove();
-            target_cell.edit();
-        }
-        this.dirty = true;
+            this.dirty = true;
+        };
     };
 
 
@@ -629,14 +622,12 b' var IPython = (function (IPython) {'
             var cell_data = this.clipboard;
             if (cell_data.cell_type == 'code') {
                 new_cell = this.insert_code_cell_above();
-                new_cell.fromJSON(cell_data);
             } else if (cell_data.cell_type === 'html') {
                 new_cell = this.insert_html_cell_above();
-                new_cell.fromJSON(cell_data);
             } else if (cell_data.cell_type === 'markdown') {
                 new_cell = this.insert_markdown_cell_above();
-                new_cell.fromJSON(cell_data);
             };
+            new_cell.fromJSON(cell_data);
             this.select_next();
             this.delete_cell();
         };
@@ -648,14 +639,12 b' var IPython = (function (IPython) {'
             var cell_data = this.clipboard;
             if (cell_data.cell_type == 'code') {
                 new_cell = this.insert_code_cell_above();
-                new_cell.fromJSON(cell_data);
             } else if (cell_data.cell_type === 'html') {
                 new_cell = this.insert_html_cell_above();
-                new_cell.fromJSON(cell_data);
             } else if (cell_data.cell_type === 'markdown') {
                 new_cell = this.insert_markdown_cell_above();
-                new_cell.fromJSON(cell_data);
             };
+            new_cell.fromJSON(cell_data);
         };
     };
 
@@ -665,14 +654,12 b' var IPython = (function (IPython) {'
             var cell_data = this.clipboard;
             if (cell_data.cell_type == 'code') {
                 new_cell = this.insert_code_cell_below();
-                new_cell.fromJSON(cell_data);
             } else if (cell_data.cell_type === 'html') {
                 new_cell = this.insert_html_cell_below();
-                new_cell.fromJSON(cell_data);
             } else if (cell_data.cell_type === 'markdown') {
                 new_cell = this.insert_markdown_cell_below();
-                new_cell.fromJSON(cell_data);
             };
+            new_cell.fromJSON(cell_data);
         };
     };
 

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

@@ -15,7 +15,6 b' var IPython = (function (IPython) {'
 
     var TextCell = function (notebook) {
         this.code_mirror_mode = this.code_mirror_mode || 'htmlmixed';
-        this.placeholder = this.placeholder || '\u0000';
         IPython.Cell.apply(this, arguments);
         this.rendered = false;
         this.cell_type = this.cell_type || 'text';
@@ -182,7 +181,7 b' var IPython = (function (IPython) {'
     // HTMLCell
 
     var HTMLCell = function (notebook) {
-        this.placeholder = "\u0000Type <strong>HTML</strong> and LaTeX: $\\alpha^2$";
+        this.placeholder = "Type <strong>HTML</strong> and LaTeX: $\\alpha^2$";
         IPython.TextCell.apply(this, arguments);
         this.cell_type = 'html';
     };
@@ -207,7 +206,7 b' var IPython = (function (IPython) {'
     // MarkdownCell
 
     var MarkdownCell = function (notebook) {
-        this.placeholder = "\u0000Type *Markdown* and LaTeX: $\\alpha^2$";
+        this.placeholder = "Type *Markdown* and LaTeX: $\\alpha^2$";
         IPython.TextCell.apply(this, arguments);
         this.cell_type = 'markdown';
     };
@@ -245,7 +244,7 b' var IPython = (function (IPython) {'
     // RSTCell
 
     var RSTCell = function (notebook) {
-        this.placeholder = "\u0000Type *ReStructured Text* and LaTeX: $\\alpha^2$";
+        this.placeholder = "Type *ReStructured Text* and LaTeX: $\\alpha^2$";
         IPython.TextCell.apply(this, arguments);
         this.cell_type = 'rst';
     };