[Haskell-cafe] Still stacking monad transformers
wren ng thornton
wren at freegeek.org
Sun Oct 12 16:54:09 EDT 2008
David Menendez wrote:
> On Sun, Oct 12, 2008 at 1:08 PM, Andrew Coppin
> <andrewcoppin at btinternet.com> wrote:
>> I am becoming extremely frustrated now. The task I want to perform is
>> simple, yet I simply cannot make Haskell do what I want.
>> I've given up hope of ever getting my program to handle infinite result sets.
> Did you miss this message?
And if you don't like that one, there's also LogicT
function you're looking for is called Control.Monad.Logic.interleave. I
know LogicT and fair disjunction were brought up earlier, though I seem
to have mislaid the post.
In case you don't like the efficient Logic or LogicT implementations of
MonadLogic, defining your own only requires that you can define msplit
:: m a -> m (Maybe (a, m a)) which pulls the first content out of your
monad without forcing the rest of it.
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