Wadler space leak
jac at informatik.uni-kiel.de
Sun Nov 7 12:47:09 EST 2010
On 02.11.2010, at 10:20, Simon Marlow wrote:
> It's not really a question of priority, rather that we don't know of
> a good way to fix it!
I would not have guessed that there exists a Haskell related problem
that cannot immediately be fixed by the ghc headquarters ; )
If I understand correctly, the problem is to keep the selectors
recognizable while still performing optimizations that might "destroy"
the selector structure. In Bertram's example the resulting expression
looked as follows.
> l : case q of (_, ys) -> case ys of
>  -> 
> _:zs -> splitBy' p zs
Is it correct that the selector is not recognizable in this case
because the right hand side fo the outermost case expression is not a
simple variable but a case expression? It is probably quite naive to
assume that the problem can be solved by looking for a structure like
case q of
(_,ys) -> e
where ys is a free variable in e. There are probably cases where
further optimizations prevent this. Or do I miss the real problem in
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