Ran into another interesting performance problem while converting a small test program over to Haskell. Let’s say that you want to walk through every line of a text file, collate character frequencies, and return anything that maps to a particular frequency. For purposes of explanation we’ll do something really silly like look for lines with [...]

I was trying to track down some issues with some text processing programs that I was writing in Haskell, and ran into an interesting problem. I made one small change and my program ended up being 5 times slower, and I had to backtrack to try and find out what it was. So, given a [...]

For comparison purposes, I was rewriting the silly little e-mail digest program in Haskell, using Python libraries for the IMAP interface (it’s available on Github). It’s hard to beat Python’s amazing collection of libraries. Cabal / hackage isn’t bad, but it doesn’t yet approach Python’s “batteries included” philosophy and ease of use. Anyway, I couldn’t [...]