On Wed, Jul 1, 2009 at 11:26 AM, Ross Paterson
On Wed, Jul 01, 2009 at 10:55:39AM -0700, Bryan O'Sullivan wrote:
Okay, here's a tentative plan that will help to figure out the answer. I'll build a fiddled base package that rewires the Monoid class to have (++) be the binary operator, and mappend as a synonym for it. I'll import the Monoid (++) into the Prelude. I'll see how much breaks. If that much builds smoothly, I'll see how much of the rest of Hackage builds, both with and without this custom base package. I'll follow up here with the results, along with a suggestion of how acceptable I think the observed level of breakage is.
Generalizing (++) will break some Haskell 98 code, e.g.
append = (++)
I think that's a show-stopper. _______________________________________________
Could we use some default rules to keep H98 code working? I don't know much about defaulting, but times = (*) works fine and defaults to type Integer. Could we not do the same thing with monoids, having monoids default to type []? Alex