memoisation function

[Klemens Hemm]

> > memoise :: (Ix a) => (a,a) -> (a -> b) -> a -> b
> > memoise bds f = (!) arr
> >   where arr = array bds [ (t,f t) | t <- range bds ]
>

when using the the memoisation function for caching functions
the cache is very forgetful.

But making the cache array a CAF brings memoisation to work.

Is this really necesarry ?

Klemens