Expressing L-systems in Rust

Just sent a couple of pull requests to make this run on stable Rust 1.0.0 (using swaps instead of the unstable drain feature), and to clarify that production rules shouldn't be able to mutate their environment (they should be pure functions). Great library, and a good introduction to how Rust's typing can make algorithm implementations a pleasure to read in code!

EDIT: Links for the curious: https://github.com/atheriel/lsystem/pull/2 https://github.com/atheriel/lsystem/pull/3

> I didn’t really want to write any graphics code, so here’s a way to cheat:

I wanted to try out Rust maybe a year ago, was thinking of writing a simple terminal app and found out that there was no way to do simple 2D graphics in Rust. Has the situation changed?

Very cool, L-systems are fascinating.

As an apropos, there was actually released a Rust implementation of Turtle graphics recently:

https://github.com/Kingdread/Rurtle