On 9/13/05, Dhaemon
Hello, I'm quite interested in haskell, but there is something I don't understand(intuitively). I've been crawling the web for an answer, but nothing talks to me... So I was hoping I could find some help here: "How is evaluating an expression different from performing action?" I'm puzzled... Doesn't it amount to the same thing? Maybe I have a wrong definition of "evaluating"(determine the value of an expression)? Examples would be appreciated. Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were "do"s everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html)
Well, most of the code is still "functional" in nature, only some of it is "imperative". And even if you're writing a very IO heavy program writing IO in Haskell is still much nicer than in traditional imperative languages since all actions are first class citizens etc. It's better to have a nice clean way of doing IO that's completely separated away from pure code than to have everything be done in a less clean imperative style always. In Haskell you have it both ways. When a functional approach is cleaner, use it, when stuff should be evaluated in sequence (not just IO, but other monads like Maybe and State as well) you do that. It all works out in a sane and clean way. /S -- Sebastian Sylvan +46(0)736-818655 UIN: 44640862