use warnings
    FATAL => 'all'
    ;
use strict;


use Test::More
  # tests => ?? + 1  # Test::NoWarnings add 1 test
    'no_plan'
    ;
use Test::NoWarnings;


my @matches = (
  '123 456 789',  qw(123.456.789  123-456-789
  123-456789  123456-789  123-456789123456  123456789123-456
  123-4-5-6-7-8-9-1-2-3-456  123-4-5-6-789
  1234-56789  123456789-123456
  123456789  123456789123456),
  qw(x123-456-789x  x123456-789x  x123456789x),
  qw(x123-456789123-456x  x123456-789123456x  x123456789123456x),
  );

my @no_matches = (  # none shall pass!
  '',  qw(a  abcdefgh  abcdefghi
  12345678  1234567891234567  123-45-678  123-4567891234-567
  -123456789  123456789-
  1-23456789  12345678-9  1-2345678-9
  12-3456789  1234567-89  12-34567-89
  -1234567891234567  1234567891234567-
  1-234567891234567  123456789123456-7  12345678-91234567
  12-34567891234567  12345678912345-67
  ),
  );


MATCHER:
for my $matcher (qw(m1)) {

    note "matching with $matcher()";
    *match = do { no strict 'refs';  *$matcher; };

    note "ALL the following should match";
    for my $n (@matches) {
         my ($m, $d) = match($n);
        ok $m, qq{match: '$n'  (diff $d)};
        }

    note "NONE of the following should match";
    for my $n (@no_matches) {
        my ($m, $d) = match($n);
        ok ! $m, qq{NO match: '$n'  (diff $d)};
        }

    }  # end for MATCHER


sub m1 {

    my ($string,
        ) = @_;

    my $diff  = qr{ [-. ]  }xms;  # differentiator chars
    my $d_min = qr{ \d{3,} }xms;  # minimum group of digits

    local our ($digits, $diffs);

    use re 'eval';

    my $ndn = qr{
        (?<! \d) (?<! $diff) $d_min
        ($diff?) (?{ $diffs = length $1; })
        (?: \d* \g{-1} (?= \d)
            (?{ $diffs && ++$diffs })
            )*
        ($d_min) (?! \d) (?(?{ $diffs }) (?! \g{-2}) | (?! $diff))
        (?(?{ $digits = $+[2] - $diffs;
              $diffs > 10 || $digits > 15 || $digits < 9 }) (*FAIL))
        }xms;

    my $match    = $string =~ $ndn;
    my $diff_seq = defined($1) ? qq{'$1'} : 'undef';

    return $match, $diff_seq;

    }  # end sub m1()