[Haskell-cafe] On to applicative

[michael rice]

Thanks, Brandon, but Ryan gave me what I was looking for.

Michael

--- On Tue, 8/31/10, Brandon S Allbery KF8NH <allbery at ece.cmu.edu> wrote:

From: Brandon S Allbery KF8NH <allbery at ece.cmu.edu>
Subject: Re: [Haskell-cafe] On to applicative
To: haskell-cafe at haskell.org
Date: Tuesday, August 31, 2010, 4:35 PM

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On 8/31/10 13:27 , michael rice wrote:
> So it's a type constructor, not a type? Could you please provide a simple
> example of its usage?

Assuming you don't mean the trivial use in defining functions, see
Control.Monad.Instances:

> instance Functor ((->) r) where
>         fmap = (.)
> 
> instance Monad ((->) r) where
>         return = const
>         f >>= k = \ r -> k (f r) r

(The above is the primitive reader functor/monad, see Control.Monad.Reader
for more information.)

- -- 
brandon s. allbery     [linux,solaris,freebsd,perl]      allbery at kf8nh.com
system administrator  [openafs,heimdal,too many hats]  allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university      KF8NH
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