Look-behind proposal in trouble

[Erik Corry]

And here's a similar playground for .Net, not by me:

http://www.regexplanet.com/advanced/dotnet/index.html

On Tue, Nov 10, 2015 at 11:08 AM, Erik Corry <erik.corry at gmail.com> wrote:

> I made a playground where you can try out regexps with lookbehind.
>
> https://dartpad.dartlang.org/8feea83c01ab767acdf1
>
> On Tue, Oct 13, 2015 at 9:24 PM, Nozomu Katoo <noz.ka at akenotsuki.com>
> wrote:
>
>> Erik Corry wrote on Tue, 13 Oct 2015 at 11:18:48 +0200:
>> > Yes, that makes sense.
>> >
>> > This could be fixed by removing {n} loops from positive lookbehinds.
>> Or by
>> > doing the .NET-style back-references immediately.
>>
>> Personally, I am reluctant to remove any feature from the current
>> proposal intentionally for a future proposal that it is uncertain
>> whether it really comes or not. It might end up only making lookbehinds
>> of ECMAScript and ones of Perl 5 incompatible.
>>
>> >> On 10/10/2015 03:48, Erik Corry wrote:
>> >>
>> >>>
>> >>> On Sat, Oct 10, 2015 at 12:47 AM, Waldemar Horwat wrote:
>> >>>
>> >>>     It's not a superset.  Captures would match differently.
>> >>>
>> >>>
>> >>> Can you elaborate?  How would they be different?
>> >>>
>> >>
>> >> If you have a capture inside a loop (controlled, say, by {n}), one of
>> the
>> >> proposals would capture the first instance, while the other proposal
>> would
>> >> capture the last instance.
>>
>> I was missing that point. I just confirmed that
>>
>>   perl -e "$a = 'abcdef'; $a =~ /(?<=.(.){2}.)./; print $1;"
>>
>> returned 'c' whereas .NET returned 'b'. Implementation based on my
>> proposal would return the same result as Perl 5.
>>
>>
>> By the way, at one point in this thread, I moved some email addresses
>> from To to Cc when sending my reply. But somehow several of them had
>> disappeared from the Cc field in the delivered email while they all
>> remain in a copy in my sent-email folder. I apologize to those who
>> received disconnected emails in this thread.
>>
>> Regards,
>>   Nozomu
>>
>>
>
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