[Haskell] debuggers

[Jared Updike]

> Debug.Trace, such as (trace (show foo) a)
> and
> System.IO.Unsafe, such as (unsafePerformIO ( print foo >> return a))

Or see this recent post, a trace that prints line and column numbers:

http://www.haskell.org//pipermail/haskell-cafe/2006-February/014723.html

  Jared.