use v5.12;
use warnings;


say "-"x10, ' ?';
for my $i (1..3) {
  say "Match $i" if
    '2' =~ m/(?{say "in $i"})$i/;
}


say "-"x10, ' ??';
for my $i (1..3) {
  say "Match $i" if
    '2' =~ m/(??{say "in $i";$i})/;
}