Why overriding a method if the new one is exactly the same of the one

in the base class?

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

@@ -1,463 +1,458
 //----------------------------------------------------------------------------
 //  Copyright (C) 2008-2012  The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // TextCell
 //============================================================================
 
 
 
 /**
     A module that allow to create different type of Text Cell
     @module IPython
     @namespace IPython
  */
 var IPython = (function (IPython) {
     "use strict";
 
     // TextCell base class
     var keycodes = IPython.keyboard.keycodes;
     var security = IPython.security;
 
     /**
      * Construct a new TextCell, codemirror mode is by default 'htmlmixed', and cell type is 'text'
      * cell start as not redered.
      *
      * @class TextCell
      * @constructor TextCell
      * @extend IPython.Cell
      * @param {object|undefined} [options]
      *      @param [options.cm_config] {object} config to pass to CodeMirror, will extend/overwrite default config
      *      @param [options.placeholder] {string} default string to use when souce in empty for rendering (only use in some TextCell subclass)
      */
     var TextCell = function (options) {
         // in all TextCell/Cell subclasses
         // do not assign most of members here, just pass it down
         // in the options dict potentially overwriting what you wish.
         // they will be assigned in the base class.
 
         // we cannot put this as a class key as it has handle to "this".
         var cm_overwrite_options  = {
             onKeyEvent: $.proxy(this.handle_keyevent,this)
         };
 
         options = this.mergeopt(TextCell,options,{cm_config:cm_overwrite_options});
 
         this.cell_type = this.cell_type || 'text';
 
         IPython.Cell.apply(this, [options]);
 
         this.rendered = false;
     };
 
     TextCell.prototype = new IPython.Cell();
 
     TextCell.options_default = {
         cm_config : {
             extraKeys: {"Tab": "indentMore","Shift-Tab" : "indentLess"},
             mode: 'htmlmixed',
             lineWrapping : true,
         }
     };
 
 
     /**
      * Create the DOM element of the TextCell
      * @method create_element
      * @private
      */
     TextCell.prototype.create_element = function () {
         IPython.Cell.prototype.create_element.apply(this, arguments);
 
         var cell = $("<div>").addClass('cell text_cell border-box-sizing');
         cell.attr('tabindex','2');
 
         var prompt = $('<div/>').addClass('prompt input_prompt');
         cell.append(prompt);
         var inner_cell = $('<div/>').addClass('inner_cell');
         this.celltoolbar = new IPython.CellToolbar(this);
         inner_cell.append(this.celltoolbar.element);
         var input_area = $('<div/>').addClass('input_area');
         this.code_mirror = new CodeMirror(input_area.get(0), this.cm_config);
         // The tabindex=-1 makes this div focusable.
         var render_area = $('<div/>').addClass('text_cell_render border-box-sizing').
             addClass('rendered_html').attr('tabindex','-1');
         inner_cell.append(input_area).append(render_area);
         cell.append(inner_cell);
         this.element = cell;
     };
 
 
     /**
      * Bind the DOM evet to cell actions
      * Need to be called after TextCell.create_element
      * @private
      * @method bind_event
      */
     TextCell.prototype.bind_events = function () {
         IPython.Cell.prototype.bind_events.apply(this);
         var that = this;
 
         this.element.dblclick(function () {
             if (that.selected === false) {
                 $([IPython.events]).trigger('select.Cell', {'cell':that});
             }
             var cont = that.unrender();
             if (cont) {
                 that.focus_editor();
             }
         });
     };
 
     // Cell level actions
     
     TextCell.prototype.select = function () {
         var cont = IPython.Cell.prototype.select.apply(this);
         if (cont) {
             if (this.mode === 'edit') {
                 this.code_mirror.refresh();
             }
         }
         return cont;
     };
 
     TextCell.prototype.unrender = function () {
         if (this.read_only) return;
         var cont = IPython.Cell.prototype.unrender.apply(this);
         if (cont) {
             var text_cell = this.element;
             var output = text_cell.find("div.text_cell_render");
             output.hide();
             text_cell.find('div.input_area').show();
             if (this.get_text() === this.placeholder) {
                 this.set_text('');
             }
             this.refresh();
         }
         if (this.celltoolbar.ui_controls_list.length) {
             this.celltoolbar.show();
         }
         return cont;
     };
 
     TextCell.prototype.execute = function () {
         this.render();
     };
 
     /**
      * setter: {{#crossLink "TextCell/set_text"}}{{/crossLink}}
      * @method get_text
      * @retrun {string} CodeMirror current text value
      */
     TextCell.prototype.get_text = function() {
         return this.code_mirror.getValue();
     };
 
     /**
      * @param {string} text - Codemiror text value
      * @see TextCell#get_text
      * @method set_text
      * */
     TextCell.prototype.set_text = function(text) {
         this.code_mirror.setValue(text);
         this.code_mirror.refresh();
     };
 
     /**
      * setter :{{#crossLink "TextCell/set_rendered"}}{{/crossLink}}
      * @method get_rendered
      * @return {html} html of rendered element
      * */
     TextCell.prototype.get_rendered = function() {
         return this.element.find('div.text_cell_render').html();
     };
 
     /**
      * @method set_rendered
      */
     TextCell.prototype.set_rendered = function(text) {
         this.element.find('div.text_cell_render').html(text);
         this.celltoolbar.hide();
     };
 
 
     /**
      * Create Text cell from JSON
      * @param {json} data - JSON serialized text-cell
      * @method fromJSON
      */
     TextCell.prototype.fromJSON = function (data) {
         IPython.Cell.prototype.fromJSON.apply(this, arguments);
         if (data.cell_type === this.cell_type) {
             if (data.source !== undefined) {
                 this.set_text(data.source);
                 // make this value the starting point, so that we can only undo
                 // to this state, instead of a blank cell
                 this.code_mirror.clearHistory();
                 // TODO: This HTML needs to be treated as potentially dangerous
                 // user input and should be handled before set_rendered.         
                 this.set_rendered(data.rendered || '');
                 this.rendered = false;
                 this.render();
             }
         }
     };
 
     /** Generate JSON from cell
      * @return {object} cell data serialised to json
      */
     TextCell.prototype.toJSON = function () {
         var data = IPython.Cell.prototype.toJSON.apply(this);
         data.source = this.get_text();
         if (data.source == this.placeholder) {
             data.source = "";
         }
         return data;
     };
 
 
     /**
      * @class MarkdownCell
      * @constructor MarkdownCell
      * @extends IPython.HTMLCell
      */
     var MarkdownCell = function (options) {
         options = this.mergeopt(MarkdownCell, options);
 
         this.cell_type = 'markdown';
         TextCell.apply(this, [options]);
     };
 
     MarkdownCell.options_default = {
         cm_config: {
             mode: 'gfm'
         },
         placeholder: "Type *Markdown* and LaTeX: $\\alpha^2$"
     };
 
     MarkdownCell.prototype = new TextCell();
 
     /**
      * @method render
      */
     MarkdownCell.prototype.render = function () {
         var cont = IPython.TextCell.prototype.render.apply(this);
         if (cont) {
             var text = this.get_text();
             var math = null;
             if (text === "") { text = this.placeholder; }
             var text_and_math = IPython.mathjaxutils.remove_math(text);
             text = text_and_math[0];
             math = text_and_math[1];
             var html = marked.parser(marked.lexer(text));
             html = IPython.mathjaxutils.replace_math(html, math);
             html = security.sanitize_html(html);
             html = $(html);
             // links in markdown cells should open in new tabs
             html.find("a[href]").not('[href^="#"]').attr("target", "_blank");
             this.set_rendered(html);
             this.element.find('div.input_area').hide();
             this.element.find("div.text_cell_render").show();
             this.typeset();
         }
         return cont;
     };
 
 
     // RawCell
 
     /**
      * @class RawCell
      * @constructor RawCell
      * @extends IPython.TextCell
      */
     var RawCell = function (options) {
 
         options = this.mergeopt(RawCell,options);
         TextCell.apply(this, [options]);
         this.cell_type = 'raw';
         // RawCell should always hide its rendered div
         this.element.find('div.text_cell_render').hide();
     };
 
     RawCell.options_default = {
         placeholder : "Write raw LaTeX or other formats here, for use with nbconvert. " +
             "It will not be rendered in the notebook. " + 
             "When passing through nbconvert, a Raw Cell's content is added to the output unmodified."
     };
 
     RawCell.prototype = new TextCell();
 
     /** @method bind_events **/
     RawCell.prototype.bind_events = function () {
         TextCell.prototype.bind_events.apply(this);
         var that = this;
         this.element.focusout(function() {
             that.auto_highlight();
             that.render();
         });
 
         this.code_mirror.on('focus', function() { that.unrender(); });
     };
 
     /**
      * Trigger autodetection of highlight scheme for current cell
      * @method auto_highlight
      */
     RawCell.prototype.auto_highlight = function () {
         this._auto_highlight(IPython.config.raw_cell_highlight);
     };
 
     /** @method render **/
     RawCell.prototype.render = function () {
         var cont = IPython.TextCell.prototype.render.apply(this);
         if (cont){
             var text = this.get_text();
             if (text === "") { text = this.placeholder; }
             this.set_text(text);
             this.element.removeClass('rendered');
         }
         return cont;
     };
 
 
     /**
      * @class HeadingCell
      * @extends IPython.TextCell
      */
 
     /**
      * @constructor HeadingCell
      * @extends IPython.TextCell
      */
     var HeadingCell = function (options) {
         options = this.mergeopt(HeadingCell, options);
 
         this.level = 1;
         this.cell_type = 'heading';
         TextCell.apply(this, [options]);
 
         /**
          * heading level of the cell, use getter and setter to access
          * @property level
          */
     };
 
     HeadingCell.options_default = {
         placeholder: "Type Heading Here"
     };
 
     HeadingCell.prototype = new TextCell();
 
     /** @method fromJSON */
     HeadingCell.prototype.fromJSON = function (data) {
         if (data.level !== undefined){
             this.level = data.level;
         }
         TextCell.prototype.fromJSON.apply(this, arguments);
     };
 
 
     /** @method toJSON */
     HeadingCell.prototype.toJSON = function () {
         var data = TextCell.prototype.toJSON.apply(this);
         data.level = this.get_level();
         return data;
     };
 
     /**
      * can the cell be split into two cells
      * @method is_splittable
      **/
     HeadingCell.prototype.is_splittable = function () {
         return false;
     };
 
 
     /**
      * can the cell be merged with other cells
      * @method is_mergeable
      **/
     HeadingCell.prototype.is_mergeable = function () {
         return false;
     };
 
     /**
      * Change heading level of cell, and re-render
      * @method set_level
      */
     HeadingCell.prototype.set_level = function (level) {
         this.level = level;
         if (this.rendered) {
             this.rendered = false;
             this.render();
         }
     };
 
     /** The depth of header cell, based on html (h1 to h6)
      * @method get_level
      * @return {integer} level - for 1 to 6
      */
     HeadingCell.prototype.get_level = function () {
         return this.level;
     };
 
 
-    HeadingCell.prototype.set_rendered = function (html) {
-        this.element.find("div.text_cell_render").html(html);
-    };
-
-
     HeadingCell.prototype.get_rendered = function () {
         var r = this.element.find("div.text_cell_render");
         return r.children().first().html();
     };
 
 
     HeadingCell.prototype.render = function () {
         var cont = IPython.TextCell.prototype.render.apply(this);
         if (cont) {
             var text = this.get_text();
             var math = null;
             // Markdown headings must be a single line
             text = text.replace(/\n/g, ' ');
             if (text === "") { text = this.placeholder; }
             text = Array(this.level + 1).join("#") + " " + text;
             var text_and_math = IPython.mathjaxutils.remove_math(text);
             text = text_and_math[0];
             math = text_and_math[1];
             var html = marked.parser(marked.lexer(text));
             html = IPython.mathjaxutils.replace_math(html, math);
             html = security.sanitize_html(html);
             var h = $(html);
             // add id and linkback anchor
             var hash = h.text().replace(/ /g, '-');
             h.attr('id', hash);
             h.append(
                 $('<a/>')
                     .addClass('anchor-link')
                     .attr('href', '#' + hash)
                     .text('¶')
             );
             this.set_rendered(h);
             this.element.find('div.input_area').hide();
             this.element.find("div.text_cell_render").show();
             this.typeset();
         }
         return cont;
     };
 
     IPython.TextCell = TextCell;
     IPython.MarkdownCell = MarkdownCell;
     IPython.RawCell = RawCell;
     IPython.HeadingCell = HeadingCell;
 
 
     return IPython;
 
 }(IPython));