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Re: Upcoming loss of usability of Emacs source files and Emacs.
From: |
Stefan Monnier |
Subject: |
Re: Upcoming loss of usability of Emacs source files and Emacs. |
Date: |
Thu, 25 Jun 2015 11:45:12 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) |
> I can't understand the doc string for macroexp-let2.
> Can anyone explain to me what this macro is supposed
> to do, and offer a concrete example of its use?
It abstracts the form:
(let ((sym (make-symbol)))
`(let ((,sym ,exp))
... ,sym ... ,sym ...))
used in macros to make sure that EXP is executed exactly one (and at
a known place with the right variables in scope), instead of the naive
`(... ,exp ... ,exp ...))
which risks running EXP too many times, or at the wrong time, or the
other naive
`(let ((val ,exp))
... val ... val ...))
which risks name capture if the `val' variable appears elsewhere.
> At this point, all I can say is that V is a metasyntactic variable,
> not literal Lisp code. So it should be capitalized, not quoted.
That's right,
Stefan
- Re: Upcoming loss of usability of Emacs source files and Emacs., (continued)
- Re: Upcoming loss of usability of Emacs source files and Emacs., Stefan Monnier, 2015/06/23
- Re: Upcoming loss of usability of Emacs source files and Emacs., Dmitry Gutov, 2015/06/23
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/23
- Re: Upcoming loss of usability of Emacs source files and Emacs., Dmitry Gutov, 2015/06/23
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/24
- Re: Upcoming loss of usability of Emacs source files and Emacs., Dmitry Gutov, 2015/06/24
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/25
- Re: Upcoming loss of usability of Emacs source files and Emacs.,
Stefan Monnier <=
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/25
- Re: Upcoming loss of usability of Emacs source files and Emacs., Stefan Monnier, 2015/06/25
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/26
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/26
- Re: Upcoming loss of usability of Emacs source files and Emacs., Stefan Monnier, 2015/06/26
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/27
- Re: Upcoming loss of usability of Emacs source files and Emacs., Paul Eggert, 2015/06/27
- Re: Upcoming loss of usability of Emacs source files and Emacs., Richard Stallman, 2015/06/28
- Re: Upcoming loss of usability of Emacs source files and Emacs., Stephen J. Turnbull, 2015/06/23
- Re: Upcoming loss of usability of Emacs source files and Emacs., Dmitry Gutov, 2015/06/23