Hi,
All Haskell functions are lazy, hence there is no need to "write a
lazy version" of your print_list function. I think the function you
probably want is:
putStr (unlines xs)
This uses the bulid in unlines function, which is similar in spirit to
join (you get more quotes, which I guess you don't want)
The equivalent in monad'y programming is:
mapM putStrLn xs
The first one has fewer monads, so I prefer it, but take your pick :)
Thanks
Neil
On 1/3/06, Daniel Carrera
Hello,
I've been studying more Haskell and I've improved a lot. But I just hit a small problem. I want to print all the elements of a linst (putStr). I'd like to write something like this:
print_list [] = do putStr "" print_list (x:xs) = (do putStr x) && print_list xs
I know this is wrong, but I hope you can see what I'm trying to do.
I know of other ways I could print a list. For example:
print_list xs = do putStr(join xs) where join [] = "" join (x:xs) = (show x) ++ "\n" ++ join xs
But the thing is, I want to write a lazy version of this function. It's not that I need such a function, I'm just trying to learn Haskell.
Any suggestions?
Question: What do you call a function that has side-effects? (like putStr) I know that "function" is the wrong term.
Cheers, Daniel. -- /\/`) http://oooauthors.org /\/_/ http://opendocumentfellowship.org /\/_/ \/_/ I am not over-weight, I am under-tall. / _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe