[Haskell-cafe] How to "Show" an Operation?
Martin Drautzburg
Martin.Drautzburg at web.de
Wed Jun 9 14:33:06 EDT 2010
On Monday, 7. June 2010 23:28:08 Evan Laforge wrote:
> I just meant you could add instances:
>
> instance Functor (Named a) where fmap f named = named { val_of = f
> (val_of named) }
> instance Applicative (Named a) where ... likewise, but maybe not a
> great fit unless you have a "no name" for 'pure'
So far so good. However my "Named" things are all functions and I don't see I
ever want to map over any of them. But what I'd like to do is use them like
ordinary functions as in:
f::Named (Int->Int)
f x
Is there a way to do this, other than writing
apply::Named Int ->Int
apply n x = (val_of n) x
--
Martin
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