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Re: RFC: Adding \p{foo=/re/}

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From:
demerphq
Date:
February 6, 2019 06:28
Subject:
Re: RFC: Adding \p{foo=/re/}
Message ID:
CANgJU+XJNLquWj7Xk9ASq2cRksyBULe4UEdhFNdPy7F_1WeX8Q@mail.gmail.com
Fwiw, I don't like it. What happens if the pattern includes capture
brackets, named recursion or eval ? This seems like a way to squeeze named
recursion concepts into the named property functionality without thinking
through the ramifications.

Yves

On Wed, 6 Feb 2019, 06:47 Karl Williamson <public@khwilliamson.com wrote:

> The Unicode Technical Standard #18 on regular expressions suggests that
> Unicode properties have what I'm calling a subpattern and they call
> wildcard properties
>
> http://www.unicode.org/reports/tr18/#Wildcard_Properties
>
> I am proposing to implement this in 5.30.  I already have a working
> prototype, which you can find in
>
> https://perl5.git.perl.org/perl.git/shortlog/refs/heads/smoke-me/khw-core
>
> and play with.  Attached is a script that exercises it to create a
> pattern that matches IPV4 addresses in any language, and fails illegal
> ones.  Thus the script would work for Bengali or Thai  numbers.  The
> motivation for this came from Abigail.
>
> Certain things aren't clear to me about how it should behave.  Should
> the default be anchored (as currently) so that you have to begin and/or
> end with '.*' to unanchor it?  I think most uses will want it anchored
> as implied by the equals sign, but that's not how other patterns behave,
> and that inconsistency probably would be too confusing.  One thing that
> might emphasize that it isn't anchored is to make them write
>
> \p{foo=~/bar/}
>
> (requiring a tilde)
>
> Comments?
>

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