[Haskell-cafe] Plain lambda inside banana brackets in the arrow notation

[Ertugrul Söylemez]

Ross Paterson <ross at soi.city.ac.uk> wrote:

> Though one possibility that might get us most of the way there would
> be to refactor the Arrow class as
>
>   class PreArrow a where
>     premap :: (b -> b') -> a b' c -> a b c

Note that you are reinventing the 'profunctors' package here.  Every
arrow forms a profunctor with the following identities:

    lmap = flip (<<^)
    rmap = fmap

or alternatively:

    rmap = (^<<)


Greets,
Ertugrul

-- 
Not to be or to be and (not to be or to be and (not to be or to be and
(not to be or to be and ... that is the list monad.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: not available
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20120715/b4ca70e6/attachment.pgp>