This one appears faster for the n > -1 case. Compared to get_proparg it is only about 7% worse for the -1 case and is about 80% faster for the 0 case: 
sub arg2 {
    my($str,$lvl)= @_;
    my $str1 = $str;
    return $str if !$lvl;
    # skip up to and including nth ( paren, then strip n ) parens from
+ end
    $str =~ /([^(]*\(){$lvl}(.+)(\)){$lvl}/;

    return $2 unless $lvl == -1;
    $str =~ /\(([^\(\)]+)\)+/;
    return $1;

}

[download]
The timing results where lvl=2 are: 
                Rate get_proparg        arg2
get_proparg 137195/s          --        -31%
arg2        199115/s         45%          --

[download]
HTH, --traveler

In reply to Re: Peeling the Peelings by traveler
in thread Peeling the Peelings by PetaMem

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