[Haskell-cafe] Composing functions with runST

[Thomas Davie]

>
> It's true that this is the typical way of learning Haskell, but I for
> one think it's a bad way of learning Haskell.
> Very few real world programs get by without the "impure" stuff, so if
> you give the newbie the impression that it isn't there (by postponing
> it) there's a chance he'll run into a situation where he needs it
> before it's been even mentioned (queue newbie going "bah, academic
> language" and switching to C++).
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 it's  
destructive to teach people "we have a wonderful new paradigm of  
programming that solves all sorts of problems, but all we're going to  
use it for is doing what we did with C++ anyway".

That's just my 2¢ -- I like Haskell specifically because I don't have  
to do things in order and I don't have to do things in an imperative  
style, I would love for more people to be taught about this wonderful  
thing.

Bob