I'm still interested in comments composition operators at
http://haskell.org/haskellwiki/TypeComposition. Now I see that my ":.::"
is what [1] calls "StaticArrow".
Mainly, I'd like to hear thoughts on how to make an arrow out of a functor &
arrow, with the functor on the inside. My attempt is called "::.:" on the
wiki page.
newtype ((~>) ::.: f) a b = TT_T {runTT_T :: f a ~> f b}
As mentioned in the comments, my Arrow definition isn't really
satisfactory. Is there an arrow that corresponds to this sort of
composition?
Thanks, - Conal
On 3/8/07, Conal Elliott
I made a first pass at a module of type compositions with some instances at http://haskell.org/haskellwiki/TypeComposition and would love to get comments & suggestions.
Is there an existing process for library proposals & discussions?
Cheers, - Conal
On 2/21/07, Ross Paterson < ross@soi.city.ac.uk> wrote:
[redirecting to libraries] On Wed, Feb 21, 2007 at 04:23:50PM -0800, Conal Elliott wrote:
Is the composition instance of Control.Applicative defined somewhere? I see it in the McBride & Paterson paper [1], but not in the library docs [2]. I'd rather pull it in from a library than (re)define it myself.
[1] http://www.soi.city.ac.uk/~ross/papers/Applicative.pdfhttp://www.soi.city.ac.uk/%7Eross/papers/Applicative.pdf [2] http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Applicati...
It's not defined in the libraries. The type (and the identity functor) should probably go in the module that defines Functor (currently Control.Monad) with a Functor instance, and an Applicative instance in Control.Applicative.
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