[m-dev.] taking the address of field access functions

[Ralph Becket]

Ian MacLarty, Friday, 30 June 2006:
> Is there some fundamental reason we don't allow passing field access
> functions as higher order terms?  I saw some comments in the compiler
> saying it wasn't allowed, but non saying *why* it wasn't allowd.  I have
> some cases where this would be useful.  Of course I can just define a
> wrapper function that calls the field access function, but I don't see
> why I shouldn't be able to pass the field access function itself.

The problem is twofold:
(1) we don't currently support "taking the address" of multi-moded
functions;
(2) field access functions are constructed on demand in order to get the
modes right regardless of context.

I would support a change to the language allowing the user to optionally
specify the usable modes for field access functions without having to
provide implementations.

I suspect that if we had parametric modes working properly (and found
some way of handling uniqueness) then this problem could be made to go
away.

-- Ralph
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