27 Jan
2006
27 Jan
'06
4:54 p.m.
On Fri, Jan 27, 2006 at 08:20:07PM +0100, Sven Biedermann wrote:
I have a problem with a function taken from class Arrow.
arr :: (b -> c) -> a b c
To build my own arrow, i need to distinguish between different kinds of b or c. For instance, if b has the form (d,e), i want to construct something different as when having form (d,e,f).
If you want a different instance in each case, then you'll need a different class: arr is polymorphic in b and c. But perhaps there's another way to do what you want. Can you give more details?