That must have been the vibe I was getting. My haskell-spider senses were tingling, I just overshot RT and went for the Halting Problem. /Joe Brandon S. Allbery KF8NH wrote:
On May 8, 2009, at 01:33 , Joe Fredette wrote:
That strikes me as being bad in a "I'm violating the Halting Problem" sort of way- but I'm not sure how. Is there some contradictory construction that could be built from such a function?
I don't think it is; surely the Haskell runtime knows which thunks it has evaluated. It just explicitly violates referential transparency, and therefore must be in IO. You may be thinking that it would return a result for _|_, but as described if you fed it _|_ it could only produce False (if the _|_ has been evaluated you would not be able to reach the test).