True, but using seq you can define deepSeq/rnf (depening on which camp you're from), which isn't misleading in this way.
-- Hal Daume III "Computer science is no more about computers | [EMAIL PROTECTED] than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume On Tue, 14 May 2002, Iavor S. Diatchki wrote: > hello, > > this is misleading. seq only evaluates to whnf, i.e. > the outermost lazy constructor (or lambda) and that only if the > "seq ..." expression is actually evaluated, which is often tricky to > ensure. furthermore, for non-functions one can get the same behaviour, > by using a case with a pattern. > > here is why i think the example does not illustrate what is seq good for: > > >>main::IO() > >>main=do > >> time1 <- getCPUTime > >> w <- return $! map undefined [1..] > >> time2 <- getCPUTime > > .... > > the above computation does not take very long. > > bye > iavor > > > Jorge Adriano wrote: > >>One may ask the question: what is seq useful for not in conjunction with > >>unsafePerformIO, other than efficiency. That, I don't know the answer to. > > > > > > Here is an example. > > > > > >>main::IO() > >>main=do > >> time1 <- getCPUTime > >> w <- return $! calcSomething > >> time2 <- getCPUTime > > > > ... > > > > J.A. > > > > _______________________________________________ > > Haskell mailing list > > [EMAIL PROTECTED] > > http://www.haskell.org/mailman/listinfo/haskell > > > > > > -- > ================================================== > | Iavor S. Diatchki, Ph.D. student | > | Department of Computer Science and Engineering | > | School of OGI at OHSU | > | http://www.cse.ogi.edu/~diatchki | > ================================================== > > _______________________________________________ > Haskell mailing list > [EMAIL PROTECTED] > http://www.haskell.org/mailman/listinfo/haskell > _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
