From: Juri Linkov <juri@linkov.net>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: Lars Ingebrigtsen <larsi@gnus.org>, emacs-devel@gnu.org
Subject: Re: Make regexp handling more regular
Date: Thu, 03 Dec 2020 23:02:10 +0200 [thread overview]
Message-ID: <87wnxya9il.fsf@mail.linkov.net> (raw)
In-Reply-To: <jwvsg8nj61j.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Thu, 03 Dec 2020 10:00:24 -0500")
>>> Currently the match data is like a dynamically bound variable accessible
>>> to the callee. But maybe the match data should be only lexically-bound?
>>> (This is just a vague idea, I don't know how to implement this.)
>> Yes, I wondered whether one could use some lexical magic here, but I
>> didn't quite see what that would look like.
>
> Actually, currently the match-data is *not* like a dynamically-scoped
> var, but like a global var. And we don't really need it to be lexically
> scoped, we would be already well-served with a dynamically-scoped var.
Notably in Ruby e.g. /(.)(.)(.)/.match("foo") returns a MatchData object:
#<MatchData "foo" 1:"f" 2:"o" 3:"o">
Shouldn't a function like string-match (or rather some new function)
return a #<MatchData> object too? Or the current list returned
by the function 'match-data' is sufficient?
Binding it to a variable will avoid the need to have global data
(unless global data is a requirement for performance). Then:
(let ((match-data (string-match regexp string)))
(list (match-beginning subexp match-data)
(match-end subexp match-data)))
with an additional arg MATCH-DATA added to match-processing functions:
(match-beginning SUBEXP &optional MATCH-DATA)
(match-end SUBEXP &optional MATCH-DATA)
(match-string NUM &optional STRING MATCH-DATA)
next prev parent reply other threads:[~2020-12-03 21:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 9:05 Make regexp handling more regular Lars Ingebrigtsen
2020-12-02 10:44 ` Lars Ingebrigtsen
2020-12-02 11:12 ` Stefan Kangas
2020-12-02 11:21 ` Philipp Stephani
2020-12-03 8:31 ` Lars Ingebrigtsen
2020-12-02 17:17 ` Stefan Monnier
2020-12-02 17:45 ` Yuan Fu
2020-12-02 19:24 ` Stefan Monnier
2020-12-03 8:40 ` Lars Ingebrigtsen
2020-12-03 8:38 ` Lars Ingebrigtsen
2020-12-03 15:10 ` Stefan Monnier
2020-12-03 16:58 ` Lars Ingebrigtsen
2020-12-03 17:40 ` Stefan Monnier
2020-12-02 21:19 ` Juri Linkov
2020-12-03 8:41 ` Lars Ingebrigtsen
2020-12-03 15:00 ` Stefan Monnier
2020-12-03 21:02 ` Juri Linkov [this message]
2020-12-03 22:20 ` Vasilij Schneidermann
2020-12-02 21:28 ` Daniel Martín
2020-12-03 4:16 ` Adam Porter
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