Re: [Haskell-cafe] How to locate a <<loop>>?

Jørgen Hermanrud Fjeld writes:

I have a generated Haskell program that emits a "Fail: <<loop>>" at runtime. Are there some tools or standard manner for identifying the lines that participate in the loop?

Provided your program does not use too many GHC extensions or fancy libraries, you could try using the Hat tracer http://haskell.org/hat which now comes with two tools called 'hat-nonterm' and 'black-hat', specially designed for finding the cycle that leads to a black hole or non-termination. Regards, Malcolm