From: Michael Heerdegen <michael_heerdegen@web.de>
To: help-gnu-emacs@gnu.org
Subject: Re: How the backquote and the comma really work?
Date: Thu, 25 Jun 2015 19:33:16 +0200 [thread overview]
Message-ID: <87r3ozy9pf.fsf@web.de> (raw)
In-Reply-To: 87vbebg1fs.fsf@mbork.pl
Marcin Borkowski <mbork@mbork.pl> writes:
> So, I assume that when Emacs Lisp interpreter encounters a backquote
It's even less mystical: backquote is just a normal macro:
C-h f ` RET
It's also a reader macro so that you can write
`thing
as an abbreviation of of
(` thing)
but that's just a detail.
> If it is a list, its element are read and scanned. If any part of the
> list (probably a nested one) begins with a comma, the whole thing after
> the comma (be it a symbol, a list or whatever) is evaluated as usual,
> and the result is put into the resulting list.
>
> Whew. Is that (more or less) right?
Seems to be a reasonable mental model. Of course, the elements have
already been read by the reader. Whether these are evaluated or not
depends on whether the macro finds the `backquote-unquote-symbol' in
front of them, so to say.
> so a bonus question is: can I find an Emacs Lisp metacircular
> evaluator (taking into account the quoting mechanisms) anywhere?
You don't need a meta thing, since backquote is completely implemented
in Elisp, just read the source code ;-)
Regards,
Michael.
next prev parent reply other threads:[~2015-06-25 17:33 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-25 17:09 How the backquote and the comma really work? Marcin Borkowski
2015-06-25 17:33 ` Michael Heerdegen [this message]
2015-06-25 18:06 ` Marcin Borkowski
2015-06-25 18:22 ` Michael Heerdegen
2015-06-25 18:39 ` Marcin Borkowski
2015-06-25 18:44 ` Marcin Borkowski
2015-06-25 19:06 ` Michael Heerdegen
2015-07-10 11:36 ` Marcin Borkowski
2015-07-12 15:54 ` Michael Heerdegen
2015-07-12 19:55 ` Marcin Borkowski
2015-07-12 20:33 ` Marcin Borkowski
2015-07-14 18:17 ` Marcin Borkowski
2015-07-14 22:08 ` Emanuel Berg
2015-07-21 22:08 ` Michael Heerdegen
2015-07-24 13:01 ` Michael Heerdegen
2015-08-11 11:41 ` Marcin Borkowski
2015-08-12 15:29 ` Michael Heerdegen
[not found] ` <mailman.8207.1439393377.904.help-gnu-emacs@gnu.org>
2015-08-12 16:30 ` Pascal J. Bourguignon
2015-08-23 8:30 ` Marcin Borkowski
[not found] ` <mailman.110.1440318650.11330.help-gnu-emacs@gnu.org>
2015-08-23 16:46 ` Pascal J. Bourguignon
2015-07-21 21:54 ` Michael Heerdegen
2015-08-11 10:15 ` Marcin Borkowski
2015-08-11 17:20 ` Thorsten Jolitz
2015-08-12 15:01 ` Michael Heerdegen
2015-07-21 21:50 ` Michael Heerdegen
2015-06-25 18:10 ` Drew Adams
2015-06-25 18:40 ` Michael Heerdegen
2015-06-25 18:53 ` Marcin Borkowski
2015-06-25 19:39 ` Michael Heerdegen
2015-06-25 20:05 ` Drew Adams
2015-06-25 20:18 ` Marcin Borkowski
2015-06-25 20:37 ` Drew Adams
2015-06-25 23:55 ` Robert Thorpe
[not found] ` <mailman.5697.1435276533.904.help-gnu-emacs@gnu.org>
2015-06-26 1:41 ` Rusi
2015-06-26 14:24 ` Michael Heerdegen
[not found] ` <mailman.5716.1435328741.904.help-gnu-emacs@gnu.org>
2015-06-26 14:35 ` Rusi
2015-06-26 14:51 ` Michael Heerdegen
2015-06-25 18:46 ` Marcin Borkowski
2015-06-26 7:31 ` tomas
2015-06-26 13:48 ` Drew Adams
2015-06-26 14:06 ` tomas
2015-06-26 15:06 ` Emanuel Berg
2015-07-12 17:38 ` Vaidheeswaran C
[not found] <mailman.5657.1435252169.904.help-gnu-emacs@gnu.org>
2015-06-30 16:27 ` sokobania.01
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