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Re^2: Evaluating code in a regex at runtime: (??{...})

by LanX (Canon)
on Jan 28, 2013 at 07:34 UTC ( #1015637=note: print w/ replies, xml ) Need Help??


in reply to Re: Evaluating code in a regex at runtime: (??{...})
in thread Evaluating code in a regex at runtime: (??{...})

> Note that the contents of the match are still accessible via a named capture group:

> ...  ('a' x 100) =~ /(?<match>(??{'(.)' x 100}))/;

ehm ... what you're showing also works with unnamed capture groups:

DB<113> ('a' x 10) =~ /((??{'(.)' x 10}))/; print "<$1>" => 1 <aaaaaaaaaa>

The OP's point was about dynamically generated capture groups, but yours is outside the embedded Perl code.

Cheers Rolf


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Re^3: Evaluating code in a regex at runtime: (??{...})
by Athanasius (Monsignor) on Jan 28, 2013 at 08:44 UTC

    Yes, you’re right. So in dave_the_m’s example, all we need to do is add another set of parentheses:

    /(....)...(...)...((??{foo()}))....(...)/ ^ ^ ^ ^ 1 2 3 4

    and the dynamically generated capture group is assigned to $3. For example:

    use Modern::Perl; my $str = 'abcd$$$$$ef'; my @caps = $str =~ /(a)b(c)d((??{'(.)' x 5}))e(f)/; say join(', ', @caps);

    Output:

    18:33 >perl 504_SoPW.pl a, c, $$$$$, f 18:38 >

    What we (apparently) can’t get is multiple capture groups matches assigned to different capture groups (whether named or unnamed) from the same dynamic match. Correct?

    Athanasius <°(((><contra mundum Iustus alius egestas vitae, eros Piratica,

      > What we (apparently) canít get is multiple capture groups assigned to different capture groups (whether named or unnamed) from the same dynamic match. Correct?

      apparently yes, like documented:

      DB<131> 'aaa' =~ /(?<outer>(??{'(?<inner>.)' x 1}))/; keys %+ => "outer"

      But of course there are workarounds ... if necessary.

      Cheers Rolf

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