Rur-ple 1.0rc

Rur-ple 1.0 is finally out ... sort of. Actually, it's a Release Candidate version. For the next little while, any free time I'll have is going to be spent on preparing my Pycon presentation (and working on Crunchy as needed to improve it before Pycon 2007). Since I had three more localizations available (German, Turkish and Welsh) than there was on sourceforge, I decided that it was better to release early. In the meantime, someone is working on an Italian localization (and possible lessons translation) which should be included in the final 1.0 version.

Pycon 2007: it's Crunch time

Yesterday I got some good news from the Pycon organizers: my proposed talk entitled Easy creation of interactive tutorials has been accepted. In this talk, I'll demonstrate how Crunchy can be used to create interactive Python tutorials. I've been thinking about how to organize my talk for about two months now but have not written a line yet. One thing I can say for sure at this time: this is not going to be your typical PowerPoint-type presentation. My current plan is to use Firefox for the presentation: one tab will display a fake html-based Python tutorial, the second tab will make use of codetch so that I can edit the same tutorial "live", and the third tab will display the resulting interactive tutorial as processed by Crunchy.

Rur-ple: double the number of languages

While I haven't had time to do programming in the past few months, some Rur-ple users have been busy and submitted new material. The upcoming 1.0 release of Rur-ple will include 3 new languages [Turkish (including a translation of most lessons), German and Welsh] as well as previously included languages [English (with all lessons), French and Spanish].

Inspired by the user contributions, I spent a few hours today re-writing the localization code. To add a new language now only requires the following:

1. Adding one line in a Python file (translation.py), that specify the language and language code, as well as the name of the .po file.
   
2. Creating a .po file containing the string translations.
3. Creating an html file (rur.htm) used as a Welcome Page in that language.

The new version will also save the last language selected and will use it upon re-starting Rur-ple.

Securing Crunchy

Following my last post, some alert readers pointed out that Crunchy could be a security risk for its users. Crunchy acts as a web server, fetching html-based Python tutorials and displaying them in your browser with controls allowing to execute the Python code. This is meant as a good thing... but it might not be if the code is allowed to run automatically when the page is loaded. In fact, this might have occurred with previous (<0.7) Johannes and I changed the way that Crunchy works so as to remove any security worries - at least, we hope so. Anyone interested can obviously look at the code; for others, here's what we do:

• Each time Crunchy starts, it generates a random session number (10 digit long).
• The javascript code used to communicate between Crunchy and the browser is fetched from a static file and modified to include the unique session number as part of each command; a new javascript file, with a filename that incorporates the session number is generated.
  
• When Crunchy fetches an html page, it processes it to remove unwanted code. This means removing all (java-)scripts and only allowing html tags that are on a "whitelist". This whitelist excludes any of the usual "onload", "oninit", etc., automatic execution.
  
• Next, Crunchy interactive elements (Python interpreter, code editor, button for Python code execution, etc.) are inserted with the javascript calls, each call given a unique identifier for that session.
• Finally, the processed page is displayed in the browser, with the server waiting for user-generated interactions.
• This procedure is repeated for any page that is loaded during that session.
  
• At the end of a session, when Crunchy is terminated, the javascript file that was generated and used in that session is deleted.

The latest version (0.7) includes this security features and many new additions [a complete list of the changes from version 0.6 is appended at the end of this message]. Currently, Johannes is working on adapting How to think like a computer scientist to use with Crunchy, as well adding new interactive features. For my part, I have been working on internationalisation issues (adding a French interface) and other configuration choices. Due to end-of-summer holidays, work on Crunchy will likely slow down for a few weeks at least but we should be able to reach version 1.0 early in the Fall.

After that, I will be ready to start implementing rur-ple inside the Crunchy environment; if there is enough interest, I might implement a turtle graphics module as well.

===== Changes from 0.6 to 0.7 ================
0. Name change
To prevent confusion with an existing program named CrunchyFrog, "Crunchy Frog" has been renamed as "Crunchy", short for "Crunchy, the Interactive Python Tutorial Maker".

1. *Security fix*
The previous versions of Crunchy allowed tutorials containing arbitrary (and hidden) javascript code to be loaded within a browser window. The new version removes any existing javascript code prior to processing for display within a browser.

Feel free to try and break this - and please report any findings back to us.

2. New functionality.

• It is possible to run external programs from within the browser; sample demos include GUI programs with 1. Tkinter, 2. pyGtk, 3. wxPython, 4. Pygame
• Automatic syntax colouring of (static) Python code, including (as an option) line numbering.
• New plotting canvas with simple to use api to draw mathematical functions
• Drawing & plotting canvas can be set to arbitrary size.
• Multiple canvas can now appear on same page.
• New addition and simplification to the sound api.
• Simplification of error message (tracebacks) more suitable for beginners.

• New plotting canvas with simple to use api to draw mathematical functions
• Drawing & plotting canvas can be set to arbitrary size.
• Multiple canvas can now appear on same page.
• New addition and simplification to the sound api.
• Simplification of error message (tracebacks) more suitable for beginners.

3. New visual design:

• Integrated menu which can be styled through custom css
• Three sample css styles now included (selectable via the browser menu)

4. New content:

• First draft sound tutorial exploring concepts of frequency, beats, harmonics (Fourier series), etc.
• New addition to the basic "Crunchy user" tutorial
• Additions to all reference documentation (sound & graphics api, vlam options, etc.)

Exciting Crunchy News

While I knew all along it could be done, I've had a lot of fun during the last two days playing with the newest, and possibly most exciting feature of "The application formerly known as Crunchy Frog", or simply "Crunchy". It is now possible, from within a Firefox windows, to click a button and launch an external Python script. (I should mention that the bulk of this latest feature was implemented by Johannes Woolard - I just had to make a few minor changes to get it working on Windows.)

I'll provide more details later, but here's the short story. You write an html document in which you insert the Python script you want to execute inside a <pre> element with some minor markup (<pre title="external copycode">); actually, you can have as many scripts you want on any given page. Crunchy processes the page, displays the Python scripts in colour (!) and makes a copy of each available for further editing inside a <textarea>. You can then just click on a button and the script is launched.

This means that Crunchy can really transform *any* Python tutorial into an interactive experience. Crunchy can load html pages from the web (not only local ones) and perform its magic ;-)

So far, I've launched Tkinter windows, wxPython apps, Pygame programs, a terminal with a Python interpreter and, the latest, a gnuplot window that ran the gnuplot demo. You can actually have a number of independent external apps going at the same time, allowing for some interesting experiments (edit the code in the <textarea> and launch the new version).

Stay tuned for more news soon, and the announcement of the next release.

Crunchy news

It's now been a month since my last blog post and a lot has happened in the meantime. We (Johannes and I) have just released a new version of Crunchy Frog. We were planning to do a release (version 0.5) a bit earlier but we kept "fixing this", "adding that little bit", "changing this", etc., until I felt it was well beyond what had been planned for the next release. So, after discussing briefly about it (at Johannes's request), we set up a roadmap for Crunchy Frog as a whole (as oppposed to just for Johannes' project) with a date set for the 1.0 release that would coincide with the end of this Summer of Code project for Johannes.

The new public release (0.6) looks very different from the previous public one (0.4). Crunchy now has its own site. Previously, Johannes had set up an svn repository which has come extremely handy. This summer of code project is supposed to be a learning experience from the student (Johannes) under the direction of a more experienced mentor (that would be me). However, I can say that it has been a huge learning experience for me. So far, I had only worked on my own project, and only very recently had learned to use an svn repository on my own computer. Working as part of a team (supposedly as the team leader [I have the final say, if need be]; in reality, it's pretty much a team of equals, each of us having different strengths) has been an experience in itself.

While we have settled on a roadmap, I can already see some additional features, not mentioned so far, that I would like to implement before the end of the summer. For those interesed in Crunchy Frog: stay tuned, there could be some very nice new stuff added soon.

The 0.6 release got some attention outside of "regular channels" and I just found out that there exists another Python project named CrunchyFrog (no space between the two words). This, I think, is most unfortunate and I am in a bit of a quandry as to what to do about the name. Note that the developper behind CrunchyFrog, who brought its existence to my attention, not only has not complained about me choosing this name, but has actually set up a link to Crunchy Frog on his own website. [This is something we'll definitely have to reciprocate; Johannes is responsible for the website and is taking a well deserved break after the last minute rush to get everything organised for the 0.6 release.] Nonetheless, the possibility of changing the name of the project has to be considered ... even though Johannes has designed a nice graphical interface based on a Frog theme.

With all this attention devoted to Crunchy Frog, Rur-ple's development has been suspended. However, just a few days ago, Michel Weinachter sent me

• a "patch" so that the user-chosen language can be remembered from one session to the next;
• an exe version, produced by py2exe, so that Windows users don't need to install Python nor wxPython to use Rur-ple;
• some simple code to make use of a clipboard within rur-ple; I have not had time to see how to make this work though;
• just today, a link to a Firefox extension useful to users of Crunchy Frog. This extension enables the "normal" use of a tab key within an html <textarea>, which comes in handy when typing Python code.

Merci Michel!

So, all in all, a busy month with lots of long nights of coding after work. I have a great job, which does not and never will require me to do any programming [sometimes, much to my chagrin.] However, as a hobby, programming in Python has really been a fantastic one. It is my hope that the programs I create will be found useful by others.

Almost there: version 0.9.9 of RUR-PLE has been released

The title of this post pretty much says it all. I just need to write a few more lessons, read over once more all the existing lessons, do once more all the suggested exercises ... and, barring any surprises, I will be ready to release version 1.0 of RUR-PLE. Thus will end an adventure that started a little less than 2 years ago, as I decided to start a new hobby and learned about Python.