Bug #14367: Wrong interpretation of backslash C in regexp literals

• Status: Open
• Priority: Normal
• Assignee: -
• Target version: -
• ruby -v: ruby 2.6.0dev (2018-01-16 trunk 61875) [x86_64-darwin15]
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
• Tags: regexp

[shyouhei (Shyouhei Urabe)]

Following ruby code returns nil.

% LC_ALL=C ruby -ve 'p(/\c\xFF/ =~ "\c\xFF")'
ruby 2.6.0dev (2018-01-16 trunk 61875) [x86_64-darwin15]
nil

Is this intentional?

[Hanmac (Hans Mackowiak)]

the problem is this:

/\c\xFF/.source == "\\c\\xFF"

which is already escaped

you might want this:

/#{"\c\xFF"}/ == /ƒ/

or use this:

Regexp.compile("\c\xFF")

PS: it is correct that i get this?

"\c\xFF" ==  "\x9F" #=> true

EDIT: this works

/\x9F/ =~ "\c\xFF" #=> 0

[shyouhei (Shyouhei Urabe)]

Hanmac (Hans Mackowiak) wrote:

the problem is this:

/\c\xFF/.source == "\\c\\xFF"

No, I believe that isn't the problem. For instance /\c\x7F/ works.

% LC_ALL=C ruby -ve 'p(/\c\x7F/ =~ "\c\x7F")'
ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin15]
0

EDIT: this works

/\x9F/ =~ "\c\xFF" #=> 0

Yeah, that's why I titled this issue a "wrong interpretation of backslash C in regexp literals". This is about /...\c.../.

[shyouhei (Shyouhei Urabe)]

Can I have any answer for my question ("Is this intentional?")?

[naruse (Yui NARUSE)]

It looks inconsistency handling between regexp and Ruby's for \c\xff:

%  LC_ALL=C ruby -ve 'p (/\c\xff/ =~ "\x1f")'
ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin18]
0