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From: Drew Adams <drew.adams@oracle.com>
To: Pedro Andres Aranda Gutierrez <paaguti@gmail.com>,
	emacs-devel <emacs-devel@gnu.org>
Subject: RE: [External] : PATCH: Explicitly show how let works on global-variables
Date: Tue, 4 Oct 2022 15:00:54 +0000	[thread overview]
Message-ID: <SJ0PR10MB54888F29304AF92906E47B44F35A9@SJ0PR10MB5488.namprd10.prod.outlook.com> (raw)
In-Reply-To: <CAO48Bk_9Wksepn2PQV-DPxGYAi4KXN6gfUQkZaFp1DV6HQrNAg@mail.gmail.com>

This isn't quite correct:

     When you use a system-wide variable in
     @code{let}, its value is modified in its
     scope and then restored.

1. I'm guessing that by "system-wide" (which is not
   defined) you mean a "special", i.e., "dynamic" var.

2. Dynamic binding has no notion of scope, actually.
   It's instead about duration: the binding has dynamic
   _extent_: it remains in effect until the `let' is
   finished.

See CLTL2, section "Scope and Extent": https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node43.html

("The term 'dynamic scope' is a misnomer. Nevertheless
it is both traditional and useful.")

      parent reply	other threads:[~2022-10-04 15:00 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-04  6:46 PATCH: Explicitly show how let works on global-variables Pedro Andres Aranda Gutierrez
2022-10-04  7:52 ` Eli Zaretskii
2022-10-04  8:09   ` Pedro Andres Aranda Gutierrez
2022-10-04 11:36     ` Phil Sainty
2022-10-04 13:43       ` Stefan Monnier
2022-10-04 22:22       ` Tim Cross
2022-10-05  5:28         ` Pedro Andres Aranda Gutierrez
2022-10-06  9:00           ` Pedro Andres Aranda Gutierrez
2022-10-06 19:34             ` Emanuel Berg
2022-10-04 17:39   ` Richard Stallman
2022-10-04  7:59 ` tomas
2022-10-04 11:56   ` Phil Sainty
2022-10-04 13:48     ` Stefan Monnier
2022-10-05 21:31     ` Richard Stallman
2022-10-04 15:00 ` Drew Adams [this message]

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