* bug#5689: looking-back-p
@ 2010-03-06 18:29 Devon Sean McCullough
2010-03-06 21:21 ` Stefan Monnier
2010-03-07 12:17 ` Andreas Röhler
0 siblings, 2 replies; 3+ messages in thread
From: Devon Sean McCullough @ 2010-03-06 18:29 UTC (permalink / raw)
To: 5689
Please include the missing looking-back-p
either as a subst like looking-at-p and string-match-p
--- lisp/subr.el.~1.667.~ 2009-11-24 22:59:23.000000000 -0500
+++ lisp/subr.el 2010-03-06 12:52:30.000000000 -0500
@@ -2984,6 +2984,12 @@
(let ((inhibit-changing-match-data t))
(looking-at regexp)))
+(defsubst looking-back-p (regexp &optional limit greedy)
+ "\
+Same as `looking-back' except this saves the match data."
+ (save-match-data
+ (looking-back regexp limit greedy)))
+
(defsubst string-match-p (regexp string &optional start)
"\
Same as `string-match' except this function does not change the match data."
or as a macro like
--- lisp/subr.el.~1.667.~ 2009-11-24 22:59:23.000000000 -0500
+++ lisp/subr.el 2010-03-06 13:18:53.000000000 -0500
@@ -2984,6 +2984,14 @@
(let ((inhibit-changing-match-data t))
(looking-at regexp)))
+(defmacro looking-back-p (&rest args)
+ "\
+Same as `looking-back' except this saves the match data.
+
+\(fn REGEXP &optional LIMIT GREEDY)"
+ `(save-match-data
+ (looking-back .,args)))
+
(defsubst string-match-p (regexp string &optional start)
"\
Same as `string-match' except this function does not change the match data."
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#5689: looking-back-p
2010-03-06 18:29 bug#5689: looking-back-p Devon Sean McCullough
@ 2010-03-06 21:21 ` Stefan Monnier
2010-03-07 12:17 ` Andreas Röhler
1 sibling, 0 replies; 3+ messages in thread
From: Stefan Monnier @ 2010-03-06 21:21 UTC (permalink / raw)
To: Devon Sean McCullough; +Cc: 5689
> Please include the missing looking-back-p
looking-back is a function that people should generally try to avoid,
because it's very costly and its behavior is not always as people
might expect. So if anything, I'd rename it to
do-something-like-looking-at-but-going-backward and would definitely
refrain from providing a "-p" alternative that would make it sound like
"it's more lightweight" even tho it's actually even worse (tho
unnoticeably so).
Stefan
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#5689: looking-back-p
2010-03-06 18:29 bug#5689: looking-back-p Devon Sean McCullough
2010-03-06 21:21 ` Stefan Monnier
@ 2010-03-07 12:17 ` Andreas Röhler
1 sibling, 0 replies; 3+ messages in thread
From: Andreas Röhler @ 2010-03-07 12:17 UTC (permalink / raw)
To: Devon Sean McCullough; +Cc: 5689
Devon Sean McCullough wrote:
> Please include the missing looking-back-p
> either as a subst like looking-at-p and string-match-p
>
> --- lisp/subr.el.~1.667.~ 2009-11-24 22:59:23.000000000 -0500
> +++ lisp/subr.el 2010-03-06 12:52:30.000000000 -0500
> @@ -2984,6 +2984,12 @@
> (let ((inhibit-changing-match-data t))
> (looking-at regexp)))
>
> +(defsubst looking-back-p (regexp &optional limit greedy)
> + "\
> +Same as `looking-back' except this saves the match data."
> + (save-match-data
> + (looking-back regexp limit greedy)))
> +
> (defsubst string-match-p (regexp string &optional start)
> "\
> Same as `string-match' except this function does not change the match data."
>
> or as a macro like
>
> --- lisp/subr.el.~1.667.~ 2009-11-24 22:59:23.000000000 -0500
> +++ lisp/subr.el 2010-03-06 13:18:53.000000000 -0500
> @@ -2984,6 +2984,14 @@
> (let ((inhibit-changing-match-data t))
> (looking-at regexp)))
>
> +(defmacro looking-back-p (&rest args)
> + "\
> +Same as `looking-back' except this saves the match data.
> +
> +\(fn REGEXP &optional LIMIT GREEDY)"
> + `(save-match-data
> + (looking-back .,args)))
> +
> (defsubst string-match-p (regexp string &optional start)
> "\
> Same as `string-match' except this function does not change the match data."
>
>
>
>
Hi Devon,
thanks a lot.
As a change usually has pros and cons, just my personal
view:
`save-match-data' changes the way of execution, I'd
like to see it expressingly.
Think code is pretty good readable as it's now.
Andreas
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-03-06 18:29 bug#5689: looking-back-p Devon Sean McCullough
2010-03-06 21:21 ` Stefan Monnier
2010-03-07 12:17 ` Andreas Röhler
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