22/07/2010
Computer science is a fascinating and maddening thing. Even the most seemingly-esoteric topics turn out to be fundamental. Go out to the fringes of CS and you find yourself smack in the middle of Philosophy. You try to understand a single point and you suddenly find yourself embracing everything.
So this post comes from that infinitely-recursive rabbit hole of wikipedia topics I’ve been falling down for the last few weeks, and you can probably expect a few more like this one; I’ll try to keep focused.
We begin (as do All Good Things) with the Untyped Lambda Calculus:
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20/05/2010
I’ve fixed a bug related to upgrading GHC to version 6.12 (thanks to Cale and the folks on haskell-cafe who helped me with the issue) and got my Befunge-93 interpreter up on hackage. The program is written in haskell (as usual). You should be able to get it soon with a:
$> cabal install Befunge93
If you want to read about how I designed it you can check out the source above, or take a look at my previous blog post.
Please report any bugs to me, and I’m also very interested in patches or suggestions for performance improvements if anyone ends up being interested in this program.
EDIT: Here is the package page: http://hackage.haskell.org/package/Befunge93
31/01/2010
I just finished an initial release of an interpreter for the befunge programming language, based on the ‘93 spec. The project was quite fun! My goal was to produce a well-designed program with performance that didn’t suck too bad. Here are some highlights:
Design
I found that writing the core functionality of the interpreter took almost no time, once I settled on the approach I would take. I used a monad transformer for the first time, StateT:
type REPL a = StateT ProgramState IO a
This let me pass around the state of the computation in the State monad while doing IO actions. This made some potentially-awkward befunge commands really easy to implement.
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