[Haskell-cafe] Curiose types

[Stefan O'Rear]

On Sun, May 27, 2007 at 02:10:40PM +0200, Stefan Holdermans wrote:
> Andrew,
> 
> >Which is beautifully symmetric. Alternatively, you can think about  
> >how you actually use it:
> >
> > map :: ((a -> b) -> [a]) -> [b]
> 
> I am not following here: what do you mean? Clearly, this is not a  
> valid typing for map. Moreover, modulo undefinedness, there are no  
> functions with this typing.

map _ = []

Stefan