[youerbt]

Thanks. This does sound like a state machine, though, but the devil is probably in the details. Yes, here Haskell is probably a bad choice, and something where direct memory manipulation is bread and butter should do better. Which is completely fine; Haskell is a high level language.

But in your example, PHP is also a bad choice, and alas, it dwarfs Haskell in popularity. I can't really think of where PHP is a great fit, but Haskell isn't.