13 Mar
2009
13 Mar
'09
11:08 a.m.
On 13 Mar 2009, at 14:32, Ross Paterson wrote:
On Fri, Mar 13, 2009 at 03:18:15PM +0100, Martijn van Steenbergen wrote:
Are there any functors f for which no point/pure/return :: a -> f a exists?
No. Choose an arbitrary element shape :: f () and define
point x = fmap (const x) shape
Correspondingly, consider the functor Const Void. Cheers Conor