Problem solved

I realized that it is a closure!

You are right. The sub counter is modified like this and it works OK.
Thank you for your help. 

#
# My fixed counter() 
#
sub counter {
    my ($from, $to, $step)= @_;
    $step ||= 1;

    return sub {
        return if $from > $to;
        my $value=$from;
        $from +=$step;
        return $value;
    };
}

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-- cmic. Life helps. Perl Too.

In reply to Re^2: iterator w/ wantarray() by cmic
in thread iterator w/ wantarray() by cmic

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