It is unsafe because, in general, lazy IO is a bad idea. In particular: foo f x = do h <- openFile x ReadMode t <- hGetContents h v <- f t hClose h return t
will do substantially different things depending on the strictness of 'f'. For instance, if 'f' is 'return . head', you might get a 'head:: empty list' error, while if 'f' is 'evaluate . head', you won't. -- Hal Daume III | [EMAIL PROTECTED] "Arrest this man, he talks in maths." | www.isi.edu/~hdaume On Sat, 18 Oct 2003, Ben Escoto wrote: > On Sun, 19 Oct 2003 02:03:58 +0200 Nick Name <[EMAIL PROTECTED]> wrote: > > You have to use unsafeInterleaveIO, wich lazily defers the IO action > > passed as an argument. Look for this function in your documentation, > > both hugs and ghc have it. > > Got it, thanks. Do you know in what sense it is "unsafe" though? Are > there some pitfalls I should be aware of? > > > -- > Ben Escoto > _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
