[racket-dev] [plt] Push #26158: master branch updated

FWIW, I think we've known about this issue for a long time and I've spent
many hour mulling over eq? and what is the right way to think about it.

In this case, I violated my own rule ("if eq? returns #f, you learned
nothing -- the same thing you'd learn as if you didn't call eq?").

Robby


On Sat, Jan 26, 2013 at 11:06 AM, Matthias Felleisen
<matthias at ccs.neu.edu>wrote:

>
> Sam, this seems to be a subtle change in semantics concerning
> interoperability that we understood but didn't think important. For the
> sake of making it all "real", I think you should collect such examples. [I
> guess Robby and I understood this in the context of contracts and it could
> all have happened if we had slapped contracts on these borders.]
>
>
>
>
>
>
>
> On Jan 26, 2013, at 11:48 AM, robby at racket-lang.org wrote:
>
> > robby has updated `master' from aaf4a2e16d to 2d2b3bee2f.
> >  http://git.racket-lang.org/plt/aaf4a2e16d..2d2b3bee2f
> >
> > =====[ One Commit ]=====================================================
> > Directory summary:
> > 100.0% collects/drracket/private/
> >
> > ~~~~~~~~~~
> >
> > 2d2b3be Robby Findler <robby at racket-lang.org> 2013-01-26 10:45
> > :
> > | fix a bug in executable creation
> > |
> > | The code used eq? to check to see if a given language was in
> > | an list of allowed-to-create-executables languages. But the
> > | language object was passing thru TR and so eq? didn't hold and
> > | thus the check was buggy.
> > :
> >  M collects/drracket/private/language-configuration.rkt | 8 +++++---
> >
> > =====[ Overall Diff ]===================================================
> >
> > collects/drracket/private/language-configuration.rkt
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > --- OLD/collects/drracket/private/language-configuration.rkt
> > +++ NEW/collects/drracket/private/language-configuration.rkt
> > @@ -85,9 +85,11 @@
> >     (define languages null)
> >
> >     (define languages-allowing-executable-creation '())
> > -    (define (language-allows-executable-creation? lang)
> > -      (and (memq lang languages-allowing-executable-creation)
> > -           #t))
> > +    (define (language-allows-executable-creation? candidate-lang)
> > +      (define candidates-positions (send candidate-lang
> get-language-position))
> > +      (for/or ([allowed-lang (in-list
> languages-allowing-executable-creation)])
> > +        (equal? (send allowed-lang get-language-position)
> > +                candidates-positions)))
> >
> >     ;; add-language : (instanceof language%) -> void
> >     ;; only allows addition on phase2
>
>
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