$str = "abracadabra";

     my @substrings;
     $str =~ m/ a (.*) a (.*)(?{push @substrings, $^N}) (?!) /x;
     use Data::Dumper 'Dumper';
     print Dumper [ @substrings ];

##</code><code>##

    my $regex="a (.*) a(.)*";
    $str =~ m/ $regex(?{push @substrings, $^N}) (?!) /x;

##</code><code>##

Eval-group not allowed at runtime, use re 'eval' in regex m/ a(.)*a(?{push @subs
trings, $^N}) (?!) / 

##</code><code>##

$str =~ m/$regex(?{push @substrings, [$^N,$pos,length $^N]}) (?!) /x;