From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Drew Adams <drew.adams@oracle.com>
Cc: Alan Mackenzie <acm@muc.de>, emacs-devel@gnu.org
Subject: Re: Can't M-x compile-defun `edebug' because dynamic variables are falsely taken as lexical.
Date: Fri, 14 Feb 2020 14:19:13 -0500 [thread overview]
Message-ID: <jwv7e0poue8.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <9a1d6af0-7561-4679-930c-3bcda6169764@default> (Drew Adams's message of "Fri, 14 Feb 2020 09:25:00 -0800 (PST)")
> The real point was about `defvar'. CL's `defvar' is
> not Emacs's, AFAIU.
That's a given. But I thought the point was about Emacs's doc.
>> In Common Lisp
>>
>> (list
>> (lambda (x)
>> (let ((y x))
>> (declare (special y))
>> (lambda (z) (+ y z))))
>> (lambda (x)
>> (let ((y x))
>> (lambda (z) (+ y z)))))
>>
>> gives you two functions that don't behave the same because the `y`
>> binding in the first is dynamically scoped whereas that same `y`
>> binding is statically scoped in the second.
>
> In CL parlance, those are not only not the same binding,
> they are not the same variable `y'. That's the point.
Not really, no: what the user wants to know is "when I write (let ((y
...)) ...), when will binding be dynamic or lexical".
Whether or not it's "the same variable" as some other
is irrelevant, or more specifically, it just shifts the problem.
> The first variable named `y' is special, which means
> that it's special everywhere (indefinite scope), and
> it's duration is the duration of the executing code
> that uses it (dynamic extent).
E.g. here it just shifts the problem from "which y will be lexical and
which will be dynamic" to "which y corresponds to this one-and-only
special var and which doesn't".
Stefan
next prev parent reply other threads:[~2020-02-14 19:19 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-03 14:14 Can't M-x compile-defun `edebug' because dynamic variables are falsely taken as lexical Alan Mackenzie
2017-01-03 18:35 ` Stefan Monnier
2017-01-03 21:32 ` Alan Mackenzie
2017-01-03 21:48 ` Stefan Monnier
2017-01-04 13:39 ` Alan Mackenzie
2017-01-04 15:23 ` Stefan Monnier
2017-01-04 20:04 ` Alan Mackenzie
2017-01-04 21:49 ` Stefan Monnier
2017-01-04 22:02 ` Alan Mackenzie
2017-01-04 22:26 ` Stefan Monnier
2017-01-04 22:44 ` Drew Adams
2017-01-05 10:54 ` Alan Mackenzie
2020-02-13 16:42 ` Drew Adams
2020-02-13 20:02 ` Stefan Monnier
2020-02-13 20:43 ` Drew Adams
2020-02-13 22:09 ` Stefan Monnier
2020-02-14 1:07 ` Drew Adams
2020-02-14 2:24 ` Stefan Monnier
2020-02-14 17:25 ` Drew Adams
2020-02-14 19:19 ` Stefan Monnier [this message]
2020-02-17 18:23 ` Drew Adams
2020-02-13 22:11 ` Stefan Monnier
2020-02-14 1:13 ` Drew Adams
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=jwv7e0poue8.fsf-monnier+emacs@gnu.org \
--to=monnier@iro.umontreal.ca \
--cc=acm@muc.de \
--cc=drew.adams@oracle.com \
--cc=emacs-devel@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.