From d6a0b66a0cf44389c7474a60dd23cbf666e78537 Mon Sep 17 00:00:00 2001 From: Stefan Monnier Date: Sat, 23 May 2020 09:33:41 -0400 Subject: [PATCH] * lisp/subr.el (save-match-data): Clarify use in docstring --- lisp/subr.el | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/lisp/subr.el b/lisp/subr.el index 33194e4ffa2..2b3231b879b 100644 --- a/lisp/subr.el +++ b/lisp/subr.el @@ -4088,7 +4088,11 @@ MODES is as for `set-default-file-modes'." ;; now, but it generates slower code. (defmacro save-match-data (&rest body) "Execute the BODY forms, restoring the global value of the match data. -The value returned is the value of the last form in BODY." +The value returned is the value of the last form in BODY. +NOTE: The convention in Elisp is that any function, except for a few +exceptions like car/assoc/+/goto-char, can clobber the match data, +so `save-match-data' should normally be used to save *your* match data +rather than your caller's match data." ;; It is better not to use backquote here, ;; because that makes a bootstrapping problem ;; if you need to recompile all the Lisp files using interpreted code. -- 2.39.5