[Haskell-cafe] Composing functions with runST
ndmitchell at gmail.com
Wed Jan 3 15:14:14 EST 2007
> On the contrary, I think it's an excellent way of learning Haskell.
> I'm writing a lot of useful Haskell code with only one IO action
> (interact). I don't think I could reasonably construct an
> introductory problem that couldn't be solved with it, and I haven't
> yet found an application for which I've needed more.
I think interact is a bit ugly. Most introductory problems are "take a
small amount of data, do something". In that case using Hugs/GHCi with
:main arguments to give in the arguments, getArgs to read them and
putStrLn to show the results is a very beautiful and does about all
that you need. Very few programs are actually interactive - if they
are they should usually get a GUI.
As for beginner issues with rank-2 types, I've been learning Haskell
for years now, and have never felt the need for a rank-2 type. If the
interface for some feature requires rank-2 types I'd call that an
abstraction leak in most cases. It certainly means that you can't
properly Hoogle for it, can't compile it with Yhc, can't do full type
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