'deriving Tree (Eq,Ord)'

[Benjamin Franksen]

On Tuesday 04 April 2006 14:55, Ross Paterson wrote:
> On Tue, Apr 04, 2006 at 11:06:59AM +0400, Bulat Ziganshin wrote:
> > how about this old proposal?
> >
> > http://www.cse.unsw.edu.au/~dons/haskell-1990-2000/msg00727.html
>
> (Making 'deriving' a separate declaration instead of a clause)
>
> Orphan instances are discouraged in the GHC libraries, so there might
> not be much support for adding a feature designed to permit orphan
> derived instances.

However, it would help programmers a lot, specialy library users. And it 
would lift some of the burden that is currently on the library writer 
to never forget to derive all possibly useful instances for public data 
types.

Ben