The topic that kept me busy most in this cycle was Python gobject-introspection, and porting pygtk2 apps to PyGI (see my initial steps and my report from the PyGI hackfest.)

To spread the love, there will be two talks about this next week: On Monday 17:00 UTC the very Tomeu Vizoso himself will explain what gobject-introspection (“GI”) is, why we need it, and how library developers use it to ship a good and useful GI binding (“typelib”) for application developers. I will then follow up on Tuesday 16:00 UTC about the app developer side, in particular how to use the GI typelibs in Python, and how to port PyGTK2 applications to PyGI.

For the most part these sessions are distribution neutral (we don’t have any special sauce for this in Debian/Ubuntu, it all happened right upstream ); only a very small fraction of it (where I explain package names, etc.) will be specific to Debian/Ubuntu, but shouldn’t be hard to apply to other distributions as well.

So please feel invited to join, and bombard us with questions!

I wondered how to present this. The commands and features I wanted to show are quite complex, and typing all of them during the presentation is too cumbersome. Besides, I’m just a lousy typer when someone else is watching. On the other hand, pasting them into classical slides is too static; I find it much easier to understand something that reveals itself step by step.

So what I needed is to prepare the chain of commands in advance, and then send them through an interactive “step by step” interpreter. A quick apt-cache search did not reveal any readymade solution, thus I hacked together a small script “shellpresent” which does exactly that:

• a line with a command gets echoed, then it waits for a keypress, then runs the command and waits for another keypress (so that you can explain the output)
• a comment line starting with # is printed in green, and doesn’t wait for a keypress
• a blank line clears the screen
• commands are prepended by a red “$” sign to indicate a command prompt

It now does exactly what I want. Perhaps it is useful for someone else out there as well.