From: akr@...
Date: 2014-01-28T10:51:06+00:00
Subject: [ruby-core:60171] [ruby-trunk - Bug #9457] [Rejected] Regexp: when using subexpression calls, returned match groups seem wrong

Issue #9457 has been updated by Akira Tanaka.

Status changed from Open to Rejected

I think it is not a bug.

The subexpression, (Tarzan|Jane), matches twice: "Tarzan" and "Jane".
So the last matched string, "Jane", is recorded in the match object.

Consider following.

    % ruby -e 'p /((Tarzan|Jane)) loves (\g<2>)/.match("Tarzan loves Jane")'
    #<MatchData "Tarzan loves Jane" 1:"Tarzan" 2:"Jane" 3:"Jane">
    % ruby -e 'p /(?<subj>(?<name>Tarzan|Jane)) loves (?<obj>\g<name>)/.match("Tarzan loves Jane")'
    #<MatchData "Tarzan loves Jane" subj:"Tarzan" name:"Jane" obj:"Jane">



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Bug #9457: Regexp: when using subexpression calls, returned match groups seem wrong
https://bugs.ruby-lang.org/issues/9457#change-44656

* Author: David Stosik
* Status: Rejected
* Priority: Normal
* Assignee: 
* Category: regexp
* Target version: 
* ruby -v: ruby 2.0.0p247 (2013-06-27 revision 41674) [x86_64-darwin12.4.0]
* Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN
----------------------------------------
Hello,

Here are a two examples:

    /(Tarzan|Jane) loves (\g<1>)/.match("Tarzan loves Jane").to_a
    #=> ["Tarzan loves Jane", "Jane", "Jane"]
    # Expected: ["Tarzan loves Jane", "Tarzan", "Jane"]

(http://rubular.com/r/We2x4XNB2l)

    /(?<name>(Tarzan|Jane)) loves (\g<name>)/.match("Tarzan loves Jane").to_a
    #=> ["Tarzan loves Jane", "Jane"]
    # Expected: ["Tarzan loves Jane", "Tarzan", "Jane"]

(http://rubular.com/r/1e3oevc1Yg)

Unless I'm wrong on the results I'm expecting, I think this is a bug.

Thanks for your help,

David



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