Three questions

Richard Hamming’s three questions for new hires at Bell Labs:

  1. What are you working on?
  2. What’s the most important open problem in your area?
  3. Why aren’t they the same?

(from R. Hamming’s You and your research. Essential reading.)

Sven’s movies

Sven Van Caekenberghe is the author of some interesting Common Lisp hacks, including KPAX, a nice (web) application framework, and cl-prevalence, which is the one that drove me to his homepage. And there i found his Lisp Movies.

Bets are seasoned common lispers will be well aware of them (the screencasts are more than a year old), but new CL aficionados or anyone wanting to see the much touted dynamism of Lisp in action will find in this couple of movies a good example of how it feels programming web applications within a really powerful environment. Sven interacts in this two-episode series with LispWorks to create a simple HTTP server (and modify it on the fly) and to write a Reddit clone in 20 minutes and 100 lines. The latter uses KPAX, so, as a bonus, you’ll get a mini-tutorial on the framework.

But of course the nicest bit is seeing how one starts with an empty but running server and modifies or, rather, debugs the program until it behaves properly. All that keeping it alive and using the tools provided by the environment (inspectors, listener, debugger) to bend and evolve the code. Ah, the Joy of REPL once again.

Easter egg

After some years playing with other implementations, i’ve been using the PLT-Scheme suite assiduously during the last weeks (more on what for in future posts), and it’s becoming, slowly but surely, my default implementation. Eli Barzilay‘s extensions to make MzScheme play nice with Emacs were the trigger, but i must say that DrScheme’s macro stepper, debugger and syntax checker (all of which i had not seriously used before) are fine pieces of hackery. If you’re into scheme, you really should take a look at them. Another strong point of PLT scheme is its excellent documentation, which comes with a browser called HelpDesk. I use it all the time, and this morning it saluted me with an unexpected background:


Let me join the toast, and wish Shriram a happy birthday too! (and, while i’m at it, thanks also for your wonderful PLAI). It must be nice being a PLTer, mustn’t it?