[Haskell-cafe] Re: [Haskell] specification of sum

[ajb at spamcop.net]

(Moving this to the cafe.)

G'day all.

Quoting Cale Gibbard <cgibbard at gmail.com>:

> We already do rely on them in most cases. Of course, not every
> property can be proved by the compiler, but many pieces of code are
> going to assume quite a lot.

Agreed.

> I think that the assumption that (+) and (*) in Num define something
> like a ring on the given type is a sensible one.

I'm not so certain.  Octonian multiplication, to pick one example, is
not associative, but I'd like to be able to use (*) nonetheless.

Cheers,
Andrew Bromage