From: Andy Wingo <wingo@pobox.com>
To: Daniel Kraft <d@domob.eu>
Cc: Ken Raeburn <raeburn@raeburn.org>, guile-devel <guile-devel@gnu.org>
Subject: Re: Elisp lexical-let
Date: Fri, 24 Jul 2009 13:42:51 +0200 [thread overview]
Message-ID: <m3k51ycnno.fsf@pobox.com> (raw)
In-Reply-To: <4A695DE1.4010500@domob.eu> (Daniel Kraft's message of "Fri, 24 Jul 2009 09:08:17 +0200")
Hi Daniel,
On Fri 24 Jul 2009 09:08, Daniel Kraft <d@domob.eu> writes:
>> It's actually fairly simple, imo. Alpha-equivalence says that
>> (lexical-let ((x a)) x) is the same as (lexical-let ((y a)) y). (Note
>> that this lexical-let corresponds to Scheme's let.) So your program is
>> the same as:
>>
>>> (lexical-let ((y 2))
>>> y ; -> 2
>>> (foo) ; -> 1
>>> (setq y 3)
>>> y ; -> 3
>>> (foo) ; -> 1
>>> (let ((x 4))
>>> x ; -> 4?
>>> (foo) ; -> 4
>>> (setq x 5)
>>> x ; -> 5
>>> (foo) ; -> 5
>>> ) ; end the let
>>> y ; -> 3?
>>> (foo) ; -> 4
>>> )
>>> x ; -> 4
>>> (foo) ; -> 4
>
> Yes of course, my main question was how the inner let is handled, and
> what dynamic values x will attain (the results of (foo)) -- and here's
> this funny stuff that the inner let will be like lexical-let for those
> variables already lexically bound.
Wow, strange. What were they thinking. But if that's the deal, that's
the deal...
Andy
--
http://wingolog.org/
prev parent reply other threads:[~2009-07-24 11:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-21 19:48 Elisp lexical-let Daniel Kraft
2009-07-21 21:46 ` Ken Raeburn
2009-07-22 9:11 ` Daniel Kraft
2009-07-22 13:00 ` Marijn Schouten (hkBst)
2009-07-22 19:24 ` Daniel Kraft
2009-07-23 15:24 ` Marijn Schouten (hkBst)
2009-07-23 16:13 ` Mark H Weaver
2009-07-23 20:53 ` Andy Wingo
2009-07-23 17:05 ` Daniel Kraft
2009-07-24 11:09 ` Marijn Schouten (hkBst)
2009-07-22 20:50 ` Ken Raeburn
2009-07-23 10:47 ` Daniel Kraft
2009-07-23 20:56 ` Andy Wingo
2009-07-24 6:50 ` Daniel Kraft
2009-07-23 20:49 ` Andy Wingo
2009-07-23 22:39 ` Andy Wingo
2009-07-24 7:08 ` Daniel Kraft
2009-07-24 11:42 ` Andy Wingo [this message]
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