From: "make_now_just (Hiroya Fujinami)" <noreply@ruby-lang.org>
To: ruby-dev@ml.ruby-lang.org
Subject: [ruby-dev:52023] [Ruby master Feature#19194] Add Regexp.linear_time?
Date: Tue, 13 Dec 2022 07:10:38 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-100618.20221213071037.9532@ruby-lang.org> (raw)
In-Reply-To: <redmine.issue-19194.20221211055433.9532@ruby-lang.org>
Issue #19194 has been updated by make_now_just (Hiroya Fujinami).
@hsbt Sorry, I'm not sure what "apply" means. May I merge the pull request on GitHub?
----------------------------------------
Feature #19194: Add Regexp.linear_time?
https://bugs.ruby-lang.org/issues/19194#change-100618
* Author: make_now_just (Hiroya Fujinami)
* Status: Assigned
* Priority: Normal
* Assignee: make_now_just (Hiroya Fujinami)
* Target version: 3.2
----------------------------------------
I suggest adding a new method named `Regexp.linear_time?` to check if matching against a given regexp can be completed in linear time by the optimization introduced in #19104 (GitHub PR [#6486](https://github.com/ruby/ruby/pull/6486)).
This method was discussed in #19104. I'm not sure the name is best.
# Example
```
Regexp.linear_time?(/a/) # => true
Regexp.linear_time?(/(a|a)*\1/) # => false, because this uses a back-reference.
# This can accept a regexp source string and flags like `Regexp.new`.
Regexp.linear_time?('a') # => true
Regexp.linear_time?('a', Regexp::IGNORECASE) # => true
```
For example, this method is useful for implementing a Rubocop rule to check a regexp is ReDoS safe.
# Implementation
Implementation is done at GitHub PR [#6901](https://github.com/ruby/ruby/pull/6901).
See the details there.
--
https://bugs.ruby-lang.org/
next prev parent reply other threads:[~2022-12-13 7:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-11 5:54 [ruby-dev:52014] " make_now_just (Hiroya Fujinami)
2022-12-12 0:56 ` [ruby-dev:52015] " mame (Yusuke Endoh)
2022-12-12 2:05 ` [ruby-dev:52016] " matz (Yukihiro Matsumoto)
2022-12-12 2:06 ` [ruby-dev:52017] " matz (Yukihiro Matsumoto)
2022-12-12 5:40 ` [ruby-dev:52020] " make_now_just (Hiroya Fujinami)
2022-12-13 7:03 ` [ruby-dev:52022] " hsbt (Hiroshi SHIBATA)
2022-12-13 7:10 ` make_now_just (Hiroya Fujinami) [this message]
2022-12-13 7:15 ` [ruby-dev:52024] " hsbt (Hiroshi SHIBATA)
2022-12-14 10:21 ` [ruby-dev:52026] " hsbt (Hiroshi SHIBATA)
2022-12-25 0:06 ` [ruby-dev:52031] " jnchito (Junichi Ito) via ruby-dev
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