On 15 October 2010 07:53, Mihai Maruseac
Hi,
Is there a way to determine the order in which thunks are created and expanded/evaluated in Haskell (GHC)? I'm looking mainly at some existing interface but if there is only something in the GHC source it will suffice.
You can use side effects to observe the order of evaluation, by wrapping observed expressions (thunks) with some IO computation inside unsafePerformIO. This is roughly what HOOD does, and it can be used to provide some clues about evaluation order, and maybe even GHood can help you visualise it. I've no idea if they work at the moment, but Hood and GHood are available on Hackage. You have to be careful of "observer effects" whereby the observation wrappers change the evaluation order of the observed code. Cheers, Bernie.