On Thu, Jul 28, 2005 at 08:01:17PM +0200, Diego y tal wrote: > I understand that this is caused by the lazyness,
No, it is caused by mixing laziness with side-effects, which happens when you use getContents/readFile. > that doesn't evaluate the expression "x <- readFile fEntrada" until > it's necessary, "x <- readFile fEntrada" is not an expression. > but.. is it normal that we have to think about this "problem" when > programming? You just have to know, which functions mix laziness and side-effects by using unsafeInterleaveIO (readFile, getContents, hGetContents). > I find this a great disadvantage as oppose of the imperative paradigm, I wouldn't say this is a great disadvantage of Haskell, because: a) the imperative paradigm is available in Haskell b) readFile is a bit of hack, because it uses laziness where the order of execution matters (it uses unsafeInterleaveIO). It is generally known that readFile should be used only for the simplest I/O tasks. c) there are other ways to complete the task (however, some of them are non-standard) Best regards Tomasz _______________________________________________ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
