using less stack

[Amanda Clare]

Thanks for all the advice. In the end, I couldn't make $! work for me 
(it always seems to be harder than I think it will be to use it, and $! 
and deepSeq makes my code run slowly). But a continuation passing style 
foldl worked wonderfully.

I now have:

 > cpsfold f a [] = a
 > cpsfold f a (x:xs) = f x a (\y -> cpsfold f y xs)

and f takes a continuation, Bob's my uncle, and I have a program that 
runs quickly in constant space!

Amanda

--
Amanda Clare  http://users.aber.ac.uk/ajc99/
Tel: +44 (0)1970 621787  Fax: +44 (0)1970 622455
Dept. of Computer Science, University of Wales, Aberystwyth, SY23 3DB