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From: "hsbt (Hiroshi SHIBATA)" <noreply@ruby-lang.org>
To: ruby-dev@ml.ruby-lang.org
Subject: [ruby-dev:52022]  [Ruby master Feature#19194] Add Regexp.linear_time?
Date: Tue, 13 Dec 2022 07:03:42 +0000 (UTC)	[thread overview]
Message-ID: <redmine.journal-100617.20221213070341.9532@ruby-lang.org> (raw)
In-Reply-To: <redmine.issue-19194.20221211055433.9532@ruby-lang.org>

Issue #19194 has been updated by hsbt (Hiroshi SHIBATA).

Status changed from Open to Assigned
Assignee set to make_now_just (Hiroya Fujinami)

I added write permission to @make_now_just now. Can you apply this by yourself? 

----------------------------------------
Feature #19194: Add Regexp.linear_time?
https://bugs.ruby-lang.org/issues/19194#change-100617

* 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/

  parent reply	other threads:[~2022-12-13  7:04 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 ` hsbt (Hiroshi SHIBATA) [this message]
2022-12-13  7:10 ` [ruby-dev:52023] " make_now_just (Hiroya Fujinami)
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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