in reply to Re^2: arithmetic in a regex ?
in thread arithmetic in a regex ?

Not elegant, but fits the spec:

/0.1|1.2|2.3|3.4|4.5|5.6|6.7|7.8|8.9|9.0/

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Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond

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Re^4: arithmetic in a regex ?
by Anonymous Monk on Nov 13, 2023 at 09:01 UTC

    Thanks for your answers.

    Does this mean, arithmetic is not possible, in this case I have to generate a list of all possible cases ?

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      You can run Perl code inside a regular expression (see perlre):

      
#!perl
use 5.020;
use Test2::V0 '-no_srand' => 1;

my @cases = (
    # case, expected result, todo text
    ['13s4', '3s4' ],
    ['3s44', '3s4' ],
    ['0a1', '0a1' ],
    ['0a2', undef ],
);

for my $case (@cases) {
    my( $line, $expected, $todo ) = @$case;
    my ($result) = $line =~ /
    (
      (\d).(\d)   # Capture the stuff
      (?(?{ $2+1 != $3 })(*FAIL)) # decide if things match our extende
+d criteria
    )/x;

    my $t; if ($todo){ $t = todo( $todo ) };
    is( $result, $expected, $line );
}

done_testing;

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