Yet another variant, which allows you to keep your original my @o.

The idea is to wrap a kind of "throw-away" subroutine around the push ... code. The subroutine is created anew every time the ?{...} code is being called. 

sub foo {
    my $window = "a b X20 c X5 d e X17 X12";
    my @o;
    my @m = ($window =~ m/(X\d+(?{(sub {push @o, @_})->(pos)}))/g);
    print join(" ", "Matches:", @m, "\n");
    print join(" ", "Offsets:", @o, "\n\n");
}

[download]

It thus is working around the closure effect of "binding" the first instance of the dynamic variable @o to the ?{...} code.

(I'm not saying that this is in any way better than the other suggestions (in particular blazar's suggestion using our @o)... but heh, Perl would only be half as much fun if there weren't always more than one way to do it :)

In reply to Re: Multiple uses of (?{ code }) do not appear to be called by almut
in thread Multiple uses of (?{ code }) do not appear to be called by bsdz

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