On Sun, 8 Aug 2010 23:47:20 +0200, bluestorm wrote:
> 
> >> > > Is there a better approach to polymorphic equality floating around?
> >> >
> >> > Besides type classes?  I'm not sure.  It's probably possible to remove
> >> > this feature from the language, with a little bit of syntactic
> >> > overhead to pass around a matching comparison function.
> >>
> >> Yes for instance the very concise local opening notation comes in handy
> >> here:
> >>
> >> if Int.(x = 42) then ... else ...
> >
> > That's very nice.  I don't think type classes are conservative enough for
> > this project, but this comes very close indeed.
> > I haven't really had a chance to explore OCaml 3.12 yet, as it came out
> > while I was working on this, but I will give this serious consideration.
> 
> This approach is very nice indeed, but to make it practical you have
> to have one of the two following features :
> - a more restricted form of "open" statement that does not blindly
> import *all* the module values

This is possible to do with Delimited Overloading (pa_do):
http://pa-do.forge.ocamlcore.org/

> - nested modules
> 
> The other way to solve the problem is to put the dangerous infix
> operators into a submodule, eg. Infix or Ops. You have a Int module
> with int-specific functions that are not likely to silently conflict
> with values of other modules, and an Int.Infix module meant to be used
> in that "local open" form : Int.Infix(x + 1 = 2).

This is possible to "import" the overloaded functions form a submodule
but has to be done by hand for the moment because there is no
consensus on what the name of the submodule should be.

My 0.02¤,
C.