Wednesday, April 22, 2009

Shed Skin 0.1.1

I have just released version 0.1.1 of Shed Skin, an experimental (restricted) Python-to-C++ compiler. It comes with 5 new example programs (for a total of 35 example programs, at over 10,000 lines) and several important improvements/bug fixes. See here for the full changelog.

The most interesting new example is minilight, an elegant raytracer (more precisely, a global illumination renderer) that utilizes triangle primitives and an octree spatial index. As shown on the minilight homepage, it becomes up to 100 times faster.

Other new examples are Peter Norvig's sudoku solver (which unfortunately doesn't become faster, but is a cool example anyway), yet another raytracer and a mastermind strategy evaluator by Raymond Hettinger.

The fifth new example, an interactive circle packing program, is especially nice, because it is, well, interactive, but also because it shows how easy it is to generate an extension module with Shed Skin and use this in a larger program (a Pygame application in this case).

The biggest improvement (if you can call it this) for this release was to drop support for generic types. This simply means that functions that can be called with different kinds of types of objects for a single argument are no longer supported (unless these types have a common base-class, of course). Similarly, generic datastructures are no longer supported. Dropping support for generic types made the compiler core a lot simpler (and 10% smaller!), and removed the need for the -i command-line option.

Seeing the compiler core shrink so much, I was inspired to further refactor several messy areas of the compiler for readability (most notably in This means the compiler core has also become a lot more readable/hackable with this release. I hope to continue this work of refactoring (and adding docstrings) with each release from now on, and invite anyone to help out here.

In general, I would really like to receive more help. For example, if someone could take over maintainership of the Windows version (and possible upgrade the MingW distribution that is packaged with it), that would be great. A suggestion on the coding side might be to add keyword support to generated extension modules (see, or to optimize some builtins (for example, string/list slicing, see lib/builtin.?pp). But I would also be happy to receive more interesting test cases (most come from a single person at the moment) and/or more bug reports (which I get far too few of.)