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| author | Stefan Monnier <monnier@iro.umontreal.ca> | 2011-09-16 10:14:48 -0400 |
|---|---|---|
| committer | Stefan Monnier <monnier@iro.umontreal.ca> | 2011-09-16 10:14:48 -0400 |
| commit | 91a15bc634398fbf5092d4116022d45bc2ec3784 (patch) | |
| tree | 39720ae0a80b9ef98ce3ad9d86b5df6c40c0d43a /src | |
| parent | e69df5166910ac0581c1ae66159b741294904006 (diff) | |
| download | emacs-91a15bc634398fbf5092d4116022d45bc2ec3784.tar.gz emacs-91a15bc634398fbf5092d4116022d45bc2ec3784.tar.bz2 emacs-91a15bc634398fbf5092d4116022d45bc2ec3784.zip | |
* src/eval.c (Fquote): Document its non-consing behavior.
Fixes: debbugs:9482
Diffstat (limited to 'src')
| -rw-r--r-- | src/ChangeLog | 4 | ||||
| -rw-r--r-- | src/eval.c | 8 |
2 files changed, 12 insertions, 0 deletions
diff --git a/src/ChangeLog b/src/ChangeLog index cf75c28c385..9ce2629d442 100644 --- a/src/ChangeLog +++ b/src/ChangeLog @@ -1,3 +1,7 @@ +2011-09-16 Stefan Monnier <monnier@iro.umontreal.ca> + + * eval.c (Fquote): Document its non-consing behavior (bug#9482). + 2011-09-16 Eli Zaretskii <eliz@gnu.org> * image.c (tiff_handler): Work around a bug in MinGW GCC 3.x (see diff --git a/src/eval.c b/src/eval.c index 57a273cd4aa..32b9d366fc3 100644 --- a/src/eval.c +++ b/src/eval.c @@ -475,6 +475,14 @@ usage: (setq [SYM VAL]...) */) DEFUN ("quote", Fquote, Squote, 1, UNEVALLED, 0, doc: /* Return the argument, without evaluating it. `(quote x)' yields `x'. +Warning: `quote' does not construct its return value, but just returns +the value that was pre-constructed by the Lisp reader (see info node +`(elisp)Printed Representation'). +This means that '(a . b) is not identical to (cons 'a 'b): the former +does not cons. Quoting should be reserved for constants that will +never be modified by side-effects, unless you like self-modifying code. +See the common pitfall in info node `(elisp)Rearrangement' for an example +of unexpected results when a quoted object is modified. usage: (quote ARG) */) (Lisp_Object args) { |