I found the code at: http://www.cs.chalmers.se/~rjmh/QuickCheck/QuickCheckM.hs The only deconstructor there for PropertyM requires a "run" function of type m Property -> Property. For IO, run is unsafePerformIO. -m Malcolm Wallace writes:

Mike Gunter wrote:

...

I'd like to use QuickCheck on IO code. For instance, I'd like to check a property of type String -> IO Bool.

Barring that, I suspect it's possible modify QuickCheck to accommodate IO code (or perhaps, general monadic code). Has anyone done this?

Yes, the original authors have. See:

"Testing Monadic Code with QuickCheck" Koen Claessen and John Hughes Haskell Workshop 2002

Regards, Malcolm _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe