From: shugo@ruby-lang.org
To: ruby-core@ruby-lang.org
Subject: [ruby-core:71756] [Ruby trunk - Bug #10891] /[[:punct:]]/ POSIX group broken (with string literals?)
Date: Mon, 30 Nov 2015 13:48:56 +0000 [thread overview]
Message-ID: <redmine.journal-55167.20151130134854.73ba35f5a5fd9ddb@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-10891.20150223122909@ruby-lang.org
Issue #10891 has been updated by Shugo Maeda.
Yui NARUSE wrote:
> It follows UTR#18's Standard Recommendation.
> http://www.unicode.org/reports/tr18/#punct
In general, it would be a reasonable choice.
However, in Ruby, the problem is that it's hard to guess the programmers intention from code,
because the behavior is decided not by the regular expression, but by the target string.
```
def do_something(s)
...
if /[[:punct:]]/ =~ s # should "<" match, or shouldn't?
...
end
...
end
```
If you want to reject symbols, `/\p{P}/` can be used instead, and it's more readable.
----------------------------------------
Bug #10891: /[[:punct:]]/ POSIX group broken (with string literals?)
https://bugs.ruby-lang.org/issues/10891#change-55167
* Author: Tom Lord
* Status: Feedback
* Priority: Normal
* Assignee: Yui NARUSE
* ruby -v: ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
The regular expression: `/[[:punct:]]/` should match the following characters:
! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~
However, it only works for these characters:
! " # % & ' ( ) * , - . / : ; ? @ [ \\ ] _ { }
And does not work for these characters:
$ + < = > ^ ` | ~
However, this is where it gets really weird... Consider the following:
60.chr == "<" # true
60.chr =~ /[[:punct:]]/ # => 0
"<" =~ /[[:punct:]]/ # => nil
So, it seems that the regular expression only fails for string literals!
--
https://bugs.ruby-lang.org/
next prev parent reply other threads:[~2015-11-30 13:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <redmine.issue-10891.20150223122909@ruby-lang.org>
2015-02-23 12:29 ` [ruby-core:68254] [Ruby trunk - Bug #10891] [Open] /[[:punct:]]/ POSIX group broken (with string literals?) lord.thom
2015-02-23 14:45 ` [ruby-core:68260] [Ruby trunk - Bug #10891] " nobu
2015-02-23 15:53 ` [ruby-core:68263] " lord.thom
2015-02-24 10:03 ` [ruby-core:68280] " lord.thom
2015-11-30 3:14 ` [ruby-core:71742] " shugo
2015-11-30 9:42 ` [ruby-core:71746] [Ruby trunk - Bug #10891] [Feedback] " naruse
2015-11-30 13:48 ` shugo [this message]
2019-07-08 1:07 ` [ruby-core:93600] [Ruby master Bug#10891] " merch-redmine
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