From: Ammar Ali <ammarabuali@...>
Date: 2010-11-25T21:50:31+09:00
Subject: Re: Regex negative look-behind bug?

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On Thu, Nov 25, 2010 at 10:41 AM, Robert Klemme
<shortcutter@googlemail.com>wrote:

>
> Done.
>
> http://redmine.ruby-lang.org/issues/show/4088
>
>

Thanks. I was too busy to follow up yesterday.

I'm glad you reported it because I'm still on the fence about it being a
bug. I think the negative match (when it matches it doesn't) and alternation
are confusing in this case.

IMHO, the following examples prove that ignoring case works as expected, but
it's difficult to verify this with when alternation is added to the mix.

Expected, not ignoring case
>> "abcd" =~ /(?<!bc)d/
nil

Expected, case differs, and it's not being ignored
>> "aBcd" =~ /(?<!bc)d/
3

Expected, case differs, but it's being ignored
>> "aBcd" =~ /(?<!bc)d/i
nil


Adding alternation is playing a part in either making it hard to tell which
part is matching, or not respecting the i option.

Thanks again,
Ammar

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