The earliest memory I have of ‘programming’ is in the early/mid 90s when my father brought home a computer from work. We could play games on it … so of course I took the spreadsheet program he used (LOTUS 123, did I date myself with that?) and tried to modify it to print out a helpful message for him. It … halfway worked? At least I could undo it so he could get back to work…

After that, I picked up programming for real in QBASIC (I still have a few of those programs lying around), got my own (junky) Linux desktop from my cousin, tried to learn VBasic (without a Windows machine), and eventually made it to high school… In college, I studied computer science and mathematics, mostly programming in Java/.NET, although with a bit of everything in the mix. A few of my oldest programming posts on this blog are from that time.

After that, on to grad school! Originally, I was going to study computational linguistics, but that fell through. Then programming languages (the school’s specialty). And finally I ended up studying censorship and computer security. That’s about where I am today!

But really, I still have a habit of doing a little bit of everything. Whatever seems interesting at the time!

Wombat IDE - New semester / bug fixes

2013-08-26

We’re about to start up the Fall semester, so it seems like a good time to be updating Wombat for the new semester. With that, a whole slew of bugs have been squashed:

'Tiny' Turing completeness without MMOV

2013-08-22

Something was bugging me about my proof from yesterday. If we take another tack on proving Turing completeness, all we would have to prove is that we can simulate SUBLEQ. Since SUBLEQ is Turing complete, that’s all we need–just convert each SUBLEQ into a SUB, JZ, and a JLS. So that means that Tiny as written should be Turing complete.

So how does that work?

A 'Tiny' virtual machine in Racket

2013-08-21

Today’s challenge at /r/dailyprogrammer asks to implement an assembler for a small virtual machine. It has only 16 mnemonics which in unique opcodes (each instruction can have multiple forms for if they’re accessing memory or literals), so it’s a simple virtual machine indeed. As a challenge, you’re supposed to write an interesting program (I actually wrote a virtual machine as well to test them). As an even better challenge, we’re supposed to prove that Tiny is Turing complete. Well, let’s get to it!

Adventures in Racket: gzip

2013-08-06

In my research, I work with a lot of rather large text files–on the order of gigabytes if not terabytes per file. Since they’re plain text, they’re generally rather compressible though, so it makes sense to gzip them while they’re on disk. The drawback though comes when you’re working with them. There are a few options though.

Authorship attribution: Part 3

2013-08-06

So far, we’ve had three different ideas for figuring out the author of an unknown paper (top n word ordering in Part 1 and stop word frequency / 4-grams in Part 2). Here’s something interesting though from the comments on the Programming Praxis post:

Globules said July 19, 2013 at 12:29 PM Patrick Juola has a guest post on Language Log describing the approach he took.

Authorship attribution: Part 2

2013-08-02

Last time, we used word rank to try to figure out who could possibly have written Cuckoo’s calling. It didn’t work out so well, but we at least have a nice framework in place. So perhaps we can try a few more ways of turning entire novels into a few numbers.

Authorship attribution: Part 1

2013-07-30

About two weeks ago, the new crime fiction novel Cuckoo’s Calling was revealed to have actually been written by J.K. Rowling under the pseudonym Robert Galbraith. What’s interesting is exactly how they came to that conclusion. Here’s a quote from Time magazine (via Programming Praxis):

Racket Roguelike: Post-mortem

2013-07-19

Almost four months ago, I started writing a series on how to write a roguelike in Racket. I believed then as I believe now that Racket is an excellent all around language and that I would like to see more done with it–particularly in games.

Racket Roguelike 10: Levels via automata!

2013-07-05

Last week we made mazes on a regular grid using the noise generators. That was pretty neat, but it got me thinking. What other ways do we have to procedurally generate interesting level patterns?

A programming puzzle: f(f(n)) = -n

2013-06-29

Two Programming Praxis puzzles in a week? Madness! Let’s do it!

This time, the puzzle at first seems rather minimal:

Write a function f so that f(f(n)) = -n for all integers n.

If you haven’t seen this problem before, take a moment to think though it. It’s a neat little problem–a close cousin to a lateral thinking puzzle.