Select Code to Download

$ perl -MDevel::Peek -e'@a=qw( a b c ); sub { Dump($_[0]) }->( $#a );'
SV = PVMG(0x1d36630) at 0x1cfcfd0
...
    MG_VIRTUAL = &PL_vtbl_arylen
    MG_TYPE = PERL_MAGIC_arylen(#)
    MG_OBJ = 0x1d07d10

use strict;
use warnings;
...

print('max($x, 4)=', max($x, 4), "\n");
print('$x=', $x, "\n");

$ perl a.pl 0
max($x, 4)=4
...
$ perl a.pl 1
max($x, 4)=5
$x=5