> When I try to execute this:
>
> > result = foldl (+) 0 [1..100000]
> > main = putStr $show (result `mod` 10)
>
> Hugs gives: ERROR: Garbage collection fails to reclaim sufficient space
> GHC gives: Stack space overflow: current size 262152 bytes.
>
> Why would this have an error? The list should be constructed lazily as it
> is consumed by the sum. I assume I have a space leak but I can't figure
> out why.
`foldl' constructs the expression ... 3+(2+(1+0)) but does not evaluate
it. A common space leak with lazy evalution, see Paulson, ML for the
working programmer, p.47. Try this one
> strictFoldl :: (Eval b) => (b -> a -> b) -> b -> [a] -> b
> strictFoldl (*) = f
> where f e [] = e
> f e (a:x) = strict f (e * a) x
> result = strictFoldl (+) 0 [1..100000]
> main = putStr $ show (result `mod` 10)
Cheers, Ralf
