From: Olaf Rogalsky <olaf.rogalsky@aol.de>
To: help-gnu-emacs@gnu.org
Subject: understanding backquote
Date: Tue, 02 Jun 2015 21:17:37 +0200 [thread overview]
Message-ID: <87mw0hly26.fsf@aol.de> (raw)
In-Reply-To: 87vbf65jem.fsf@free.fr
Hi,
I have problems in understanding the semantics of backquote. Consider
the following function:
(defun test () `,(* (+ 1 2) (+ 3 4)))
Now let's have a look at the defintion of the symbol:
(symbol-function 'test)
=> (lambda nil (* (+ 1 2) (+ 3 4)))
Huhh??? I was thinking, that the above definition is equivalent to the
following:
(defun test () 21)
Ok, this was unexpected, but perhaps the compiler does it "right":
(disassemble (byte-compile 'test))
=> byte code:
args: nil
0 constant 21
1 return
Yes, it does. It is only, that I suspect, that this has nothing to do
with backquotes, but rather with constant folding optimization.
Can anybody explain this to me?
Thanks,
Olaf
next prev parent reply other threads:[~2015-06-02 19:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-02 13:28 gtags-find-tag and gtags-find-rtag in C-code Peter Münster
2015-06-02 15:06 ` Eli Zaretskii
2015-06-02 16:01 ` Peter Münster
2015-06-02 16:13 ` Eli Zaretskii
2015-06-02 19:09 ` Dmitry Gutov
2015-06-02 20:34 ` Peter Münster
2015-06-02 19:17 ` Olaf Rogalsky [this message]
2015-06-03 11:05 ` understanding backquote Nicolas Richard
[not found] ` <mailman.4231.1433345880.904.help-gnu-emacs@gnu.org>
2015-06-03 18:53 ` Stefan Monnier
[not found] ` <mailman.4175.1433272668.904.help-gnu-emacs@gnu.org>
2015-06-02 20:03 ` Pascal J. Bourguignon
2015-06-02 23:00 ` Olaf Rogalsky
2015-06-03 10:40 ` Nicolas Richard
[not found] ` <mailman.4191.1433286041.904.help-gnu-emacs@gnu.org>
2015-06-02 23:08 ` Pascal J. Bourguignon
2015-06-02 21:22 ` Barry Margolin
2015-06-02 22:53 ` Olaf Rogalsky
[not found] ` <mailman.4189.1433285612.904.help-gnu-emacs@gnu.org>
2015-06-02 23:07 ` Pascal J. Bourguignon
2015-06-02 23:54 ` Olaf Rogalsky
[not found] ` <mailman.4193.1433289260.904.help-gnu-emacs@gnu.org>
2015-06-03 1:14 ` Stefan Monnier
2015-06-03 7:57 ` Olaf Rogalsky
2015-06-03 10:23 ` Olaf Rogalsky
2015-06-03 2:37 ` Pascal J. Bourguignon
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