Issue #5961 has been reported by Anthony Bourque.

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Bug #5961: regular expression positive look-behind
https://bugs.ruby-lang.org/issues/5961

Author: Anthony Bourque
Status: Open
Priority: Normal
Assignee: Anthony Bourque
Category: core
Target version: 1.9.3
ruby -v: 1.9.3p0


irb(main):001:0> input = " \t Jeffs "
=> " \t Jeffs "
irb(main):002:0> input.gsub(%r{(?<=\bJeff)(?=s\b)},"'")
SyntaxError: (irb):2: invalid pattern in look-behind: /(?<=\bJeff)(?=s\b)/
        from E:/Ruby/Ruby193/bin/irb:12:in `<main>'
irb(main):003:0>

This is a valid regular expression which should produce " \t Jeff's ". It seems to have a problem with the \b in the look-behind.


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