printf-debugging

coming from the Ocaml community, I'm trying to learn a bit of Haskell. The transition goes quite well but I'm a bit confused with debugging. I used to put (lots of) "printf" in my ocaml code, to inspect some intermediate values, or as flag to see where the computation exactly failed. Since printf is an IO action, do I have to lift all my haskell code inside the IO monad to be able to this kind of debugging ? Or is there a better way to do this (I really don't want to do it by hand if it can be avoided) I also find the trace function : http://www.haskell.org/haskellwiki/Debugging#Printf_and

There are many ways of doing debugging, using a debugger is one, but the simple one for the humble, lazy, programmer is to just add a bunch of print statements to your code. i.e. def foo(x): print 'Hey wow, we got to foo!', x ... print 'foo is returning:', bar return bar Is there a proper name for this style of debugging? Yes - it's known as printf() debugging , named after the ubiquitous C function: Used to describe debugging work done by inserting commands that output more or less carefully chosen status information at key points in the program flow, observing that information and deducing