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). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH