9 Jun
2003
9 Jun
'03
4:52 a.m.
On Fri, Jun 06, 2003 at 10:19:40AM +0100, Ross Paterson wrote:
On Fri, Jun 06, 2003 at 09:14:18AM +0100, Simon Peyton-Jones wrote:
That is, deriving works for arbitrary classes for newtypes, just using the instance for the representation type. This greatly alleviates the pain you refer to. It's documented in the GHC user manual.
I recall that you came across a glitch with the specification of this feature -- is that all sorted out now?
There is of course the obvious glitch that "the instance for the representation type" is _not_ used as is when deriving Read or Show. An understandable special case, but still a bit ugly. Lauri Alanko la@iki.fi