[Haskell-cafe] ANNOUNCE fmlist
sebf at informatik.uni-kiel.de
Thu Jun 18 05:28:02 EDT 2009
On Jun 18, 2009, at 9:57 AM, Sjoerd Visscher wrote:
> I am pleased to announce the first release of Data.FMList, lists
> represented by their foldMap function: [...]
Just for fun: a derivation translating between different formulations
of monadic bind.
m >>= g
= flatten (fmap g m)
= FM $ \f -> unFM (fmap g m) (foldMap f)
= FM $ \f -> unFM (FM $ \f' -> unFM m (f' . g)) (foldMap f)
= FM $ \f -> (\f' -> unFM m (f' . g)) (foldMap f)
= FM $ \f -> unFM m (folfMap f . g) -- your definition
= FM $ \f -> unFM m (flip unFM f . g)
= FM $ \f -> unFM m (\x -> flip unFM f (g x))
= FM $ \f -> unFM m (\x -> unFM (g x) f) -- like
Underestimating the novelty of the future is a time-honored tradition.
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 163 bytes
Desc: This is a digitally signed message part
Url : http://www.haskell.org/pipermail/haskell-cafe/attachments/20090618/24a592d5/PGP.bin
More information about the Haskell-Cafe