Wednesday, January 31, 2007

Lightning talk?

Living in a small village in Nova Scotia, 300 km from the nearest city (Halifax, pop.: 380,000), the opportunities to discuss face to face with other pythonistas are non-existent. This is one reason I've been really looking forward to going to my first Pycon. In addition to my scheduled talk, I have been thinking about giving a lightning talk of a different kind, but still touching upon a subject dear to me, that is the promotion of Python and its use as a teaching language. While lightning talks are so short that they normally touch upon only one topic, I was thinking of actually covering three topics, under the common theme of "interactive tutorials". These three topics are, from the more serious to the semi-frivolous:

1. The fate of input() and raw_input() in Python.
2. Using a distinctive logo for promoting interactive tutorials using Python.
3. Creating an interactive tutorial repository.

According to this, both input() and raw_input() are supposed to disappear in Python 3.0. After thinking about it for quite some time, I posted a message on edu-sig about the proposed change last September, expressing my "opposition" to the proposed change, and seeking the opinion of others on this topic. After a while, a near-consensus emerged, supporting the idea of keeping at least something like raw_input() in Python 3.0. I then wrote a pre-PEP, which generated more positive comments and encouragements but otherwise no further action from other edu-sig subscribers more involved in the Python community than I am. Unfortunately, due to my work, I had to drop all my Python-related activities for a few months and was not able to follow up until late December. With the end of the year approaching, I found the time to incorporate the comments received on edu-sig and offered a revised pre-PEP to the Python 3000 list on December 22nd. This was a single posting from me as I don't subscribe to that list. A bit of discussion ensued after which Guido stated that he like the proposal better than any of the other alternatives mentioned and, later, suggested that someone should "clean up and check in the proto-PEP and start working on an implementation or patch."

Unfortunately, and perhaps because this happened just before the holidays, nothing further was done. So, I'm thinking about raising the issue again at Pycon. Having something like raw_input() is, I believe, nearly essential for using interactive tutorials of the kinds produced by crunchy in a teaching environment aimed at beginners.

Further on the topic of interactive tutorials, I have been thinking of an easy means to identify them. For those that have tried crunchy, you will have noticed that an interactive tutorial viewed through a regular browser without using crunchy appears to be nothing else than your average (W3C compliant) html document. Since such tutorials could be included on any web site, I was thinking it might be useful to give a visual clue to crunchy users. There already exist a Python logo to identify applications, namely:
I've been thinking of asking the Python software foundation for the permission to modify this logo, replacing the word "powered" by "interactive", and adding a small change to crunchy so that every tutorial created with it would automatically have the logo added at the top. I'm debating whether I should do this prior to Pycon, or wait until I get the chance to lobby for it in person.

Finally, if enough people start writing interactive tutorials using crunchy, I thought it might be useful to have a central repository somewhere. Moving away from the Monty Python references, I thought that the Snake PIT (for Python Interactive Tutorials) might be a catchy name.

So, for you, patient reader that has made it this far, does it sound like a worthwhile for a Lightning talk, especially if it is supplemented by a one-minute demo of an interactive tutorial? I'm pretty sure I could cover all three topics above in less than the scheduled 5 minutes for a lightning talk, as I would not have to go into much detail about the history; just the facts...

Saturday, January 27, 2007

Crunchy 0.8 is out

Version 0.8 of Crunchy has been released. It is available at its new home on

Crunchy, the Interactive Python Tutorial Maker, is an application that
transforms an ordinary html-based Python tutorial into an interactive
session within a web browser. Currently, only Firefox is supported.
Crunchy is developed and tested on Windows XP and Ubuntu Dapper Drake,
but should work on any suitable windows or UNIX system.

Three major improvements have been made since version 0.7 had been released.

1. New editor

Instead of a simple html textarea, Crunchy now gives the option of
using a "real" editor, namely EditArea. EditArea support syntax coloring
and allows loading and saving local Python files among other features.
Within Crunchy, it is set up so that the tab key is translated into 4

2. Language support

Crunchy now supports English and French, through the use of ".po"
files. When running Python code, some error messages have been
adapted/translated. EditArea itself support more languages
(currently: Danish, Dutch, English, French, German, Italian, Japanese,
Polish, Portuguese).

3. Graphical tutorial converter.

Crunchy uses some supplementary markup to transform html files into
interactive tutorials. Whereas previous versions required a tutorial
maker to edit an html file "by hand", version 0.8 includes a tutorial
editor: with a few clicks, you can easily add to an html file the
chosen interactive elements and options for Crunchy.

In addition to the above major improvements, the code has been
refactored significantly and a number of small bug fixes have been
made. Crunchy will be demonstrated at the upcoming Pycon 2007.

The next release will likely have a new, simplified API for tutorial writers, but with more powerful features, thanks to the work of Johannes Woolard. Unfortunately, it is unlikely to be ready in time for Pycon. Anyone planning to go to Pycon, and who is interested in Crunchy should feel free to contact me with any questions/suggestions they may want to have me address during my presentation.

Wednesday, January 10, 2007

Pycon 2007: it's Crunch time - take 2

Well, it's done: I've registered for Pycon, booked a hotel room and bought plane tickets. Since November 1, when I first heard that my talk had been accepted, crunchy has changed quite a bit and my planned presentation will have to change. One demo I had planned to do, using codetch, and which I thought would take about 5 minutes will now be doable in less than 30 seconds without having to use anything else than the "new and improved" crunchy. Unfortunately, there has been so much changed since the last release that the documentation has to be re-organized significantly - this means that I can't really do a new release right now as it would likely be too confusing. So, I'm racing against the clock to put everything together to do a new release before Pycon. However, if some of you are interested in having a preview, drop me an email and I'll let you know where you can get the code from and give a quick description of how to use the new features.
Looking at the official statistics, I find the relatively small numbers of attendees compared with last year somewhat disappointing. Given that more talks are going to be presented this year, with a much larger rejection rate, I find this rather puzzling. I imagine the organizers are rather disappointed.

Wednesday, January 03, 2007

Unicode headaches ... and a solution

Work on Crunchy has restarted by both Johannes and I over the holidays, after a few months long hiatus. Hopefully, we'll be in a position to do a new release soon (just a few more features...). Among the changes, Crunchy now has a proper embedded editor, EditArea. See this example to get an idea of what EditArea can do. Actually, the Python support has since been improved by Christophe Dolivet, the creator of EditArea, prompted by a few suggestions of my own, but the new version has not been made publicly available yet. It is however already used in the development version of Crunchy, and, with a few additions of my own, will definitively be showcased during my Pycon presentation.

Other Crunchy changes include a proper handling of English and French translations. Now, since EditArea's tooltips are available in many more language, I thought I should use a more complete encoding (like utf-8) rather than the one I normally use (latin-1). After all, if rur-ple has been found useful enough to be adapted to 6 languages (with Italian and Chinese in the pipeline), I figured that Crunchy is likely to eventually see the same kind of adaptation.

However, I soon encountered a most puzzling bug. All strings translated were properly rendered by Firefox except for those coming out of an interpretor session (some tracebacks have been customized and translated in French as well as being available in English). When French was selected as the default language, whenever an accented letter, like à, was supposed to appear as a result of a Python output, a ? instead was displayed.

After trying all kind of encoding/decoding tricks over the course of a few hours, I remembered that I had set the default sytem encoding on my computer to latin-1. I decided to change it to utf-8 and, sure enough, everything was working as expected. Success at last!

However, this was only the beginning of my problems. My favourite editor, SPE, stopped working. I also tried to run rur-ple which failed miserably. [Idle, on the other hand, which I use very rarely, was still working perfectly.] Clearly, changing the site default encoding was not an appropriate solution: I could certainly not depend on having a crunchy user set his or her site customization to utf-8. A different approach was needed.

After reverting back to latin-1 as my default python site encoding (so that paths that included my name, André, were properly read by SPE) and poring over the code, I finally figured out a more general solution.

Whenever Crunchy executes some Python code written by a user (or provided by a tutorial writer), it starts a Python interpreter in a separate thread. This Python interpreter uses the default system encoding for all its computation. When the result needs to be sent back by the Crunchy server to Firefox, it needs to have its encoding changed as

result = result.decode(sys.getdefaultencoding()).encode('utf-8')

Of course, in retrospect, it all makes sense but it did stump me for quite a few hours; perhaps the information included here will save a few minutes or hours to someone else.