[Haskell-cafe] Categories in base

[David Menendez]

On 10/14/07, Jean-Philippe Bernardy <jeanphilippe.bernardy at gmail.com> wrote:
> instance Arrow a => Functor (a r) where  -- (not defined as such in base, but
> ad-hoc)
>     f <$> g = pure f . g

Similarly:

instance Arrow a => Applicative (a r) where
    return a = pure (const a)
    a <*> b = pure (\(f,x) -> f x) . a &&& b

-- 
Dave Menendez <dave at zednenem.com>
<http://www.eyrie.org/~zednenem/>