<div dir="ltr">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.<div><br></div><div>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?").</div>
<div><br></div><div style>Robby</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Sat, Jan 26, 2013 at 11:06 AM, Matthias Felleisen <span dir="ltr"><<a href="mailto:matthias@ccs.neu.edu" target="_blank">matthias@ccs.neu.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
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.]<br>
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On Jan 26, 2013, at 11:48 AM, <a href="mailto:robby@racket-lang.org">robby@racket-lang.org</a> wrote:<br>
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> robby has updated `master' from aaf4a2e16d to 2d2b3bee2f.<br>
> <a href="http://git.racket-lang.org/plt/aaf4a2e16d..2d2b3bee2f" target="_blank">http://git.racket-lang.org/plt/aaf4a2e16d..2d2b3bee2f</a><br>
><br>
> =====[ One Commit ]=====================================================<br>
> Directory summary:<br>
> 100.0% collects/drracket/private/<br>
><br>
> ~~~~~~~~~~<br>
><br>
> 2d2b3be Robby Findler <<a href="mailto:robby@racket-lang.org">robby@racket-lang.org</a>> 2013-01-26 10:45<br>
> :<br>
> | fix a bug in executable creation<br>
> |<br>
> | The code used eq? to check to see if a given language was in<br>
> | an list of allowed-to-create-executables languages. But the<br>
> | language object was passing thru TR and so eq? didn't hold and<br>
> | thus the check was buggy.<br>
> :<br>
> M collects/drracket/private/language-configuration.rkt | 8 +++++---<br>
><br>
> =====[ Overall Diff ]===================================================<br>
><br>
> collects/drracket/private/language-configuration.rkt<br>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>
> --- OLD/collects/drracket/private/language-configuration.rkt<br>
> +++ NEW/collects/drracket/private/language-configuration.rkt<br>
> @@ -85,9 +85,11 @@<br>
> (define languages null)<br>
><br>
> (define languages-allowing-executable-creation '())<br>
> - (define (language-allows-executable-creation? lang)<br>
> - (and (memq lang languages-allowing-executable-creation)<br>
> - #t))<br>
> + (define (language-allows-executable-creation? candidate-lang)<br>
> + (define candidates-positions (send candidate-lang get-language-position))<br>
> + (for/or ([allowed-lang (in-list languages-allowing-executable-creation)])<br>
> + (equal? (send allowed-lang get-language-position)<br>
> + candidates-positions)))<br>
><br>
> ;; add-language : (instanceof language%) -> void<br>
> ;; only allows addition on phase2<br>
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</blockquote></div><br></div>