[Haskell-cafe] Where do you use Haskell?

[Daniel Carrera]

Hi all,

Again, I'm the new guy slowly learning this "fuctional programming" 
thing. :-)

I've been reading, and I'm really liking the elgance of Haskell, and FP 
as a whole. But I wonder about the range of applicability. You see, one 
of the things about FP is that there are no side-effects and the same 
function on the same parameters always returns the same value. But any 
program that interacts with the real world cannot meet those properties.

The function ask_user_name() will not return the same value each time. 
If write a chess program, the function get_user_move() will be different 
each time. And every time you update the screen, you're having a 
side-effect.

So, I figure that to do these tasks you heed that "do ... <-" work 
around. But that kills the whole point of using FP in the first place, 
right?

So, I'm tempted to conclude that FP is only applicable to situations 
where user interaction is a small part of the program. For example, for 
simulations.

Now, I'm sure I'm not the first person to have this train of thought. 
And I'm sure there is a good answer why I'm wrong. :-) I'm eager to hear 
what that might be.

Cheers,
Daniel.