I think the only time they're not potentially contradictory is when you're
dealing with singletons, and that's a pretty special case.
On Wed, Oct 27, 2021, 11:15 AM Carter Schonwald
not necessarily ... there could be contradictory sets of methods! :)
like the minimal sets for Field type class, the xor would be for defining '/' in terms of reciprocal and times or vice versa (/ vs recip) and likewise (negate vs minus) etc etc
On Wed, Oct 27, 2021 at 6:38 AM Henning Thielemann < lemming@henning-thielemann.de> wrote:
On Mon, 25 Oct 2021, Carter Schonwald wrote:
i agree with Tom and Hecate,more strongly:
https://github.com/ghc/ghc/blob/98aa29d3fe447cce3407e6864b015892244bb475/lib...
the current definition DOES NOT require defining both.
as it currently stands, you only need to define one of '==' XOR '/='
this actually suggests an interesting and DIFFERENT ecosystem improvement, (ignoring IEEE non-signalling NANs), namely we add support for XOR to minimal pragma syntax and issue a warning
perhaps something like adding (XOR "reason String" clauseExpr1 clauseexpr2) ?
The problem of implementing two methods in a contradictory way arises for any OR in MINIMAL pragma, right?
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