[racket-dev] [plt] Push #27395: master branch updated

I'll fix `generic-set?''s type to work with `Set's as hash sets.

Vincent


At Fri, 30 Aug 2013 17:40:18 -0700,
Eric Dobson wrote:
> 
> As it stands the Set type constructor is for hash sets. Changing that
> would break backwards compatibility and pr13989 is for the issue of
> changing the meaning/any change.
> 
> I think there is a bunch of existing code that assumes that Set is
> exactly hashsets, or at least covariant.
> 
> On Fri, Aug 30, 2013 at 5:37 PM, Vincent St-Amour <stamourv at ccs.neu.edu> wrote:
> > I was thinking of the `Set' type constructor as meaning generic set,
> > which is why I gave that type to `generic-set?'. This interpretation is
> > a problem because TR treats sets as covariant.
> >
> > If we make sets invariant, could TR support generic sets? [1] Or are
> > there other issues I'm missing?
> >
> > Vincent
> >
> >
> > [1] Better support would also include subtyping between lists and sets.
> >
> >
> > At Fri, 30 Aug 2013 16:38:11 -0700,
> > Eric Dobson wrote:
> >>
> >> Isn't the assymetric check the wrong way? If it returns true, we know
> >> nothing because it might not be a hash-set, but if it returns false
> >> then we know that it is not a hash set?
> >>
> >> On Fri, Aug 30, 2013 at 3:30 PM, Asumu Takikawa <asumu at ccs.neu.edu> wrote:
> >> > On 2013-08-30 16:15:23 -0400, Sam Tobin-Hochstadt wrote:
> >> >> I worry about mutable sets here, but I can't think of any bugs it can
> >> >> cause ATM.
> >> >
> >> > I don't have any segfault-causing bugs, but here's a violation of the blame
> >> > theorem:
> >> >
> >> >   #lang racket
> >> >
> >> >   (module a0 racket
> >> >     (define s (mutable-set 1 2 3))
> >> >     (provide s))
> >> >
> >> >   (module a typed/racket
> >> >     (require/typed (submod ".." a0) [s Any])
> >> >     (: x (Setof Any))
> >> >     (define x (assert s generic-set?))
> >> >     (provide x))
> >> >
> >> >   (require 'a)
> >> >   x
> >> >
> >> > Cheers,
> >> > Asumu
> >> > _________________________
> >> >   Racket Developers list:
> >> >   http://lists.racket-lang.org/dev