From: Mark H Weaver <mhw@netris.org>
To: Andy Wingo <wingo@pobox.com>
Cc: Peter TB Brett <peter@peter-b.co.uk>, guile-devel@gnu.org
Subject: Re: mark uniqueness
Date: Tue, 24 Jan 2012 19:26:36 -0500 [thread overview]
Message-ID: <87r4yor5j7.fsf@netris.org> (raw)
In-Reply-To: <87mx9clu9p.fsf_-_@pobox.com> (Andy Wingo's message of "Tue, 24 Jan 2012 21:28:50 +0100")
Andy Wingo <wingo@pobox.com> writes:
> (define-syntax-rule (define-const x val)
> (begin
> (define t val)
> (define-syntax x (identifier-syntax t))))
>
> Here, `t' will have a fresh mark.
>
> Now, if in one compilation unit, I do:
>
> (define-const x 10)
>
> And in another, I do:
>
> (let ((t 20))
> x) => ?
>
> You would expect the result to be 20. But I think it could be 20, if
> the marks on the two "t"s happened to collide.
Ah yes, indeed you are right. Thanks for this explanation. I guess we
need universally-unique gensyms for marks at least, regardless of which
`local-eval' implementation we use.
Thanks,
Mark
next prev parent reply other threads:[~2012-01-25 0:26 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-15 17:00 syntax-local-binding Andy Wingo
2012-01-15 17:22 ` syntax-local-binding Andy Wingo
2012-01-19 11:41 ` syntax-local-binding Andy Wingo
2012-01-20 20:26 ` syntax-local-binding Mark H Weaver
2012-01-20 21:23 ` syntax-local-binding Andy Wingo
2012-01-20 22:03 ` syntax-local-binding Mark H Weaver
2012-01-22 0:03 ` syntax-local-binding Ludovic Courtès
2012-01-23 16:05 ` syntax-local-binding Andy Wingo
2012-01-23 21:03 ` syntax-local-binding Mark H Weaver
2012-01-23 22:19 ` syntax-local-binding Andy Wingo
2012-01-24 2:11 ` syntax-local-binding Mark H Weaver
2012-01-24 11:42 ` syntax-local-binding Andy Wingo
2012-01-24 17:29 ` syntax-local-binding Noah Lavine
2012-01-24 10:30 ` syntax-local-binding Peter TB Brett
2012-01-24 10:38 ` syntax-local-binding David Kastrup
2012-01-24 11:26 ` syntax-local-binding Andy Wingo
2012-01-24 13:25 ` syntax-local-binding Mark H Weaver
2012-01-24 20:28 ` mark uniqueness (Was: Re: syntax-local-binding) Andy Wingo
2012-01-25 0:26 ` Mark H Weaver [this message]
2012-01-25 9:02 ` mark uniqueness Andy Wingo
2012-01-24 21:22 ` syntax-local-binding Andy Wingo
2012-01-25 2:30 ` syntax-local-binding Mark H Weaver
2012-01-25 7:49 ` syntax-local-binding Stefan Israelsson Tampe
2012-01-25 11:18 ` syntax-local-binding Andy Wingo
2012-01-25 13:18 ` syntax-local-binding Ludovic Courtès
2012-01-25 18:08 ` syntax-local-binding Mark H Weaver
2012-01-26 11:21 ` syntax-local-binding Andy Wingo
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