Category Archives: Programming

Roadmap For Gonzales 0.02

For version 0.02 I have the following features in mind:

  1. A simple help system, that shows you the most important features in a consistent way
  2. A snippet system like the ones from Textmate and Scribes. Probably I will steal most of the code from Scribes. Mysteelef’s snippet system is just awesome.
  3. Auto – Indentation hast to be build, especially for Python programming. I think IDLE is working quite fine with Python 🙂 The other languages will become a simpler auto-indentation system.
  4. A way to load a file via command line in one instance of the editor.
  5. Right now the status messages in the status bar are only dummies. I will have to find a way of refresh the state of the status bar.
  6. I want some kind of recent files dialog. Simular to the recent files dialog of Emacs. I think wxPython doesn’t provide any facilities for that, so I have to write it by my self.
  7. Intelligent logging of events and properties. That point needs a lot of thought, what do I want to track, maybe the size of the window, etc.
  8. Auto braces. Here again I will borrow a lot from Scribes. The way the braces work in Scribes is just gorgeous.
  9. Better highlighting. Gonzales needs more highlighting files for languages different from Python
  10. Develop ideas for shortcuts – I have to think about the best use of shortcuts. This is a crucial part of the user experience. A lot of nice ideas can be found on

That’s it for version 0.02. It is a awful lot of work 🙂 But I think after version 0.02 is finished Gonzales could be usable for simple programming tasks.

Gonzales 0.01 Is Out

I played around with the idea of programming my own editor.

I finished my first iteration which I call version 0.01. It is of course more a kind of a prototype than a complete editor. But like every iteration/version it includes 10 new features. (Ergo version 0.1 will include 100 features.)


Now lets introduce the features with screen shots and explanation:

1. Basic Design Ideas (Opera, web2.0 style [rtm, gmail])

Gonzales Main Window + File Switcher

Gonzales Main Window + File Switcher

Gonzales got an reduced window without menu and icons to save screen space and lead the user to the use of shortcuts. The file switcher works like the one from Opera. If you use <Ctrl>+<Tab>, Gonzales show you the last used file. Colors will probably change until version 0.1

2. Autosave (no save as…)

Gonzales saves your file every time it looses focus. There is no such thing like “save” or “save as …”. Every time you create a new file you will be asked for a name and you have to stick to it. If you want to change names you have to use a file manager or something similar.

3. Spaces Instead Of Tabs

All Tabs will be converted to spaces at the moment. Like most features it can easily changed in the configuration files.

4. Tab Width 4 Spaces

This one is closely related to feature 3. Tabwidth is set to 4 spaces.

5. Show Dot For Space

Gonzales shows a dot for every space. This is especially useful for programming python. It can be easily changed in the configuration file.

6. Loading Of File Via Command Line

You can load files via command line. I know this is nothing special, but it was an important feature for me. Right now there is no server to open a new file in a running instance of Gonzales. This will be implemented soon.

7. Set The Right Working Directory

A quite complex algorithm determines which is the current working directory of Gonzales. Usually it is the one of the active file.

8. Simple Open Dialog

Simple Open File Dialog

A Simple Open File Dialog

Gonzales has a rather simple open dialog, it will get pimped later, but I needed a solution for opening files for testing purposes. If you enter an absolute path this path will be used. If you enter a relative path it is relative to the current working dir.

9. Gonzales Closes If Last Tab Is Closed.

Some of you might know this feature from a Firefox plugin. If you close the last tab,
you close the whole app.

10. Basic Syntax-Highlighting

Python Syntax-Highlighting

Python Syntax-Highlighting

Gonzales has syntax highlighting for Python implemented. Highlighting for other languages can now be easily added trough configuration files.


If you want to download Gonzales and play around with it:

The code is GPL3. Tell me what you think.

Sketch Number 3

The last sketch shows the same window again, but with a bigger bottom pane. Again this idea is stolen from Emacs. The bottom pane opens like a canvas for a projector to show the results of a some certain operation.

Programming Editor Sketch 3

Sketch with big bottom pane

This is how it work in Emacs for the “occur” command:


The bottom pane of Emacs when the occur command is used.

This way it is possible to make the find and editing experience as smooth as possible.

Next time I will show the first screens of the user-interface.

Sketch Number 2

Sketch # 2 show an entry field at the bottom. This entry field shall be used for most user entries. This idea is of course stolen from Emacs. The idea is that you can run a lot of commands from there, even if you don’t know the shortcut for the command.

Programming Editor Sketch 2

Sketch 2 - See the entry field at the bottom

I probably will use the classic “Alt-x” or better “M-x” shortcut for the entry field. This is meant as a homage to Emacs.

This little field seams not very significant, but I think it helps a lot to

  • give the user a lot of power and
  • streamlining the editing experience

at the same time.

First Sketch Of My New Editor

Last time I wrote about a new programming and text editing experience and how the interface of such an editor should behave.

The other night I could not sleep hence I used the time to wonder about the look of the editor’s interface.

I draw a simple sketch:

Programming Editor Sketch 1

Programming Editor Sketch 1

At first look the interface doesn’t seem so special. The most eye-catching differences are:

  • no menu bar
  • no toolbar

The Rest is pretty straight forward.

  • Tabs (that will probably work like Opera’s)
  • Status bar with Last Action, columns lines, etc.
  • Line numbers on the left

Just as a reminder. The goal of the interface is that is never in your way and that you never need the mouse. Nevertheless the interface should go conform with important common interface standards.

A New Text Editing Experience

I am unsatisfied of the state of programming editors. At the moment there is no editor that suits all my needs. Don’t get me wrong there are several great text editors out there:

  • Emacs – The most powerful text editing system ever created
  • Scribes – A simply and nevertheless powerful.
  • Peppy – A simpler Emacs in Python

but no one works perfect for me.
Emacs for example has different short cuts than most other software (Yeah, I know you can change that), Schribes only works on Linux, etc.

Designing A New Experience

After searching and experimenting for the perfect editor, I was thinking: “Why not writing a new one?”. After all there is a lot to learn. At first I was thinking about the widget toolkit and features. Then is struck me. Designing from scratch means thinking beyond technical details.

I want a new editing experience:

  1. I want to learn from web apps like Remember The Milk and GMail
  2. I want to streamline the experience, there should be nothing that gets in your way
  3. The interface should be gorgeous. I think that is not emphasized enough in most editors.
  4. The editor should speed you up. Think snippets, call tips, auto completion, etc.
  5. The editor shall be lean.

Then I started experimenting with code…

Pyjamas Tutorial Part 3

This tutorial series is based on the Getting Started tutorial for GWT.

Part 2: Building the User Interface

At this point, you’ve created all the elements of the interface. Like many user interface frameworks, Pyjamas is event-based. This means that the code executes in response to some event occurring. Most often, that event is triggered by the user, who uses the mouse or keyboard to interact with the application interface.

In this section, you’ll wire up your widgets to listen for and handle mouse and keyboard events.

  1. Review the functional requirements.
  2. Listen for events.
  3. Respond to events.
  4. Test event handling.

1. Reviewing the requirements for event handling

Let’s review the StockWatcher requirements to see what events occur.

Task UI Event (Trigger mechanism) Response
User enters a stock code. Clicks the Add button
or presses return in the input box.
  • Verify input.
  • Check to see if stock already exists.
  • Add a new row.
  • Create a delete button.
User deletes stock from the table. Presses the Remove button.
  • Remove row from table.

provides a number of different event handler interfaces. To handle click events on the Add and Remove buttons, you’ll use the build in ClickHandler class of the Button. To handle keyboard events in the input box, you’ll use the KeyPressHandler class.

2. Listening for events

Event Handler Classes

Events in Pyjamas use the event handler model similar to other user interface frameworks. To subscribe to an event, you pass a particular event handler interface to the appropriate widget. An event handler class defines one or more methods that the widget then calls to announce (publish) an event.

Handling Mouse Events

One way StockWatcher users can enter a stock code is by using their mouse to click on the Add button.

You’ll handle the Add button’s click event by just assigning a function to the button, which fires when the user clicks on the widget.

When the user clicks on the Add button, StockWatcher should respond by adding the stock to the stock table. So, to handle the click event, call the addStock method. You haven’t written the addStock method yet; you’ll create a stub and then code it in the next section.

  1. Add a function handler to the Add button so it can receive click events.
    In, in the onModuleLoad method, cut and paste the code commented “Listen for mouse events on the Add button.” that is highlighted below.
  2. In, create the stub for the addStock method.
    Just copy and paste from the code highlighted below.
    from pyjamas.ui.RootPanel import RootPanel
    from pyjamas.ui.VerticalPanel import VerticalPanel
    from pyjamas.ui.FlexTable import FlexTable
    from pyjamas.ui.HorizontalPanel import HorizontalPanel
    from pyjamas.ui.TextBox import TextBox
    from pyjamas.ui.Button import Button
    from pyjamas.ui.Label import Label
    from pyjamas import Window
    class Stockwatcher:
        # Entry point method.
        def __init__(self):
    #        declare interface widgets
            self.mainPanel = VerticalPanel()
            self.stocksFlexTable = FlexTable()
            self.addPanel = HorizontalPanel()
            self.newSymbolTextBox = TextBox()
            self.addStockButton = Button("Add", getattr(self, "addStock"))
            self.lastUpdatedLabel = Label()
        def addStock(self):
    # Add stock to FlexTable. Executed when the user clicks the
    # addStockButton or presses enter in the newSymbolTextBox.
        def onModuleLoad(self):
            # Create table for stock data.
            self.stocksFlexTable.setText(0, 0, "Symbol")
            self.stocksFlexTable.setText(0, 1, "Price")
            self.stocksFlexTable.setText(0, 2, "Change")
            self.stocksFlexTable.setText(0, 3, "Remove")
            # Assemble Add Stock panel.
            #Assemble Main panel.
            #Associate the Main panel with the HTML host page.
            # Move cursor focus to the input box.
    if __name__ == '__main__':
        app = Stockwatcher()

Handling Keyboard Events

In addition to using the Add button, StockWatcher users can enter a stock code without taking their hands from the keyboard by pressing return in the input box.

To subscribe to keyboard events, you can call the addKeyPressHandler(KeyPressHandler) method and pass it a KeyPressHandler.

    Hook up the keypress event handler for the input box, newSymbolTextBox.
    In the Stockwatcher class, cut and paste the code that is highlighted below.
        def onKeyDown(self, sender, keycode, modifiers):
        def onKeyUp(self, sender, keycode, modifiers):
        def onKeyPress(self, sender, keycode, modifiers):
            if sender == self.newSymbolTextBox and \
               keycode == KeyboardListener.KEY_ENTER:

The event handlers are now wired up and ready for an event. Your next step is to fill out the stub addStock method.

3. Responding to user events

At this point, StockWatcher should be listening for user input, a mouse or keyboard event that signals the user has entered a stock code. So next you’ll test whether or not the event handler interfaces are working by coding the response that StockWatcher should make when it detects an event: add the stock. StockWatcher responds on the client side without sending any requests back to server or reloading the HTML page.

Adding the stock to the stock table

In StockWatcher, users will enter the stock codes of the stocks they want to monitor one at a time into the input box. When they press Enter or click on the Add button, you want StockWatcher to respond as follows:

  1. Validate the input.
  2. Check for duplicates.
  3. Add the stock.
  4. Add a button for removing the stock from the list.

In this section, you’ll code the first response, validating the input, just to see if the event handler interfaces are working. In the next section, Coding Functionality on the Client, you’ll code the rest of the steps to add the stock.

You’ll implement this functionality in the addStock method.

Validating input in a text box

You want verify that the stock code entered is valid. Rather than verify whether the user input matches an actual stock code, for the purposes of this tutorial, you’ll just perform a simple character validity check.

First, extract the stock code. To retrieve the text in the TextBox widget use its getText method.

Next, ensure that the charcters are not within the set of illegal characters you specify. After you’ve converted the user input to a standard form, use a regular expression to check its format. Remember to use regular expressions.

If the input is valid, clear the text box so the user can add another stock code.

Finally, if the input is not valid, warn users via a dialog box.

  1. Validate user input of the stock code.
    In replace the stub addStock method with following code.
    def addStock(self):
    # Add stock to FlexTable. Executed when the user clicks the
    # addStockButton or presses enter in the newSymbolTextBox.
            symbol = self.newSymbolTextBox.getText()
            symbol = symbol.upper().strip()
            if not testRegEx(symbol):
                Window.alert("Please choose a different name than %s.\n\
                                    The Name should only contain number \
                                     and characters" % (symbol))
        # TODO Don't add the stock if it's already in the table.
        # TODO Add the stock to the table.
        # TODO Add a button to remove this stock from the table.
        # TODO Get the stock price.
  2. Test the regular expression in Javascript.
    I didn’t figured out how to test regular expression with pyjamas yet. So you have to define this function in your
    def testRegEx(string):
        """Test a regular expression"""
            var re = new RegExp("^[0-9a-zA-Z\s]{1,30}$");
            return re.test(string);

4. Testing event handling

At this point you should be able to enter text in the input box. If you use an illegal character, a dialog box should pop up and display a warning. Try it and see.

  1. Test event handling in hosted mode.
  2. Test that both event handler interfaces work.
    Enter stock codes in the input box. Enter using both methods, by pressing return and by using the mouse to click on the Add button.
    At this point, the stock is not added to the table. However, the input box should clear so that you can add another stock.
  3. Test the validity checking and error message.
    Make some typos that include illegal characters.

Validation Error Message

What’s Next

At this point you’ve implemented event handler interfaces for mouse and keyboard events that signal the user has entered a stock. Stockwatcher responds by validating the input.

From now on, you should be able to go on your own.

You could improve the client that it adds the stock to the table and provide a button to remove it. See the original Google tutorial for inspiration.

Portions of this page are modifications based on work created and shared by Google and used according to terms described in the Creative Commons 2.5 Attribution License.