{
    my @inserts;
    sub gf
    {
        @inserts = ();
        my $ins1 = '4 A -4 C -4 B 1 D';
        print "\nat the beginning: " . \@inserts . "\n";
        print $ins1, "\n";
        my $re = qr/[\d+-]+(?: \w ([\d+-]+)(?{print \@inserts, "\n"; push @inserts, $1}))*/;
        $ins1 =~ /$re/g;
        print "\n" . join ' ', @inserts;
    }
}