The 90 Minute Scheme to C compiler

90 minute video presentation from Marc Feeley, along with accompanying PowerPoint slides and source code, for a Scheme to C compiler. Good discussion of continuations and closures, as well as some dipping into the area of compiler construction.

I didn’t work through this but it looks like it might be a fun project to undertake (I’ll add it to the list).
(via LtU)

Advice on writing teachpacks

Here is some advice on writing teachpacks for PLT’s DrScheme.
About teachpacks:

Teaching languages are small subsets of a full programming language. While such restrictions simplify error diagnosis and the construction of tools, they also make it impossible (or at least difficult) to write some interesting programs. To circumvent this restriction, it is possible to import teachpacks into programs written in a teaching language.
In principle, a teachpack is just a library written in the full language, not the teaching subset. Like any other library, it may export values, functions, etc. In contrast to an ordinary library, however, a teachpack must enforce the contracts of the “lowest” teaching language into which it is imported and signal errors in a way with which students are familiar at that level.

XO Critical Configuration 1

Until a recent trip, I hadn’t used the XO very hard, or configured it at all. Before heading out, I read Bill’s article and found some real gems that, along with my own preferences, make using the XO a much more pleasurable experience. They follow:

OLPC XO OS build 703 changes

OLPC XO OS build 703 has at least two significant changes:
The first is that it automatically suspend when closed, with this caveat:

the system can’t suspend when the USB bus is in use by an external device (unless it’s a USB mass storage device and has been fully allowed to write any cached info and quiesce itself).

This might not seem like a big deal, but folks have been wanting it for a long time.
The second is that activities no longer come pre-installed in the OS image.