First class modules
Thu, 9 Nov 2000 03:04:33 +1100
On 07-Nov-2000, Tom Pledger <Tom.Pledger@peace.com> wrote:
> Supposing that (some version of) Haskell had first class modules, and
> type variables could be universally quantified at the module level,
> would rule 2 of the monomorphism restriction go away?
| Rule 2. Any monomorphic type variables that remain when type
| inference for an entire module is complete, are considered
| ambiguous, and are resolved to particular types using the
| defaulting rules (Section 4.3.4).
Although this rule refers to the "entire module", its typical for
the ambiguity to arise within a single function:
foo = show (read "whatever")
This expression is fundamentally ambiguous unless you somehow
disambiguate what type it is that you are trying to read.
I don't see how first class modules could solve that.
Fergus Henderson <firstname.lastname@example.org> | "I have always known that the pursuit
| of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.