$n = 1; 
$m = 2; 
print \$n, \$m;;
SCALAR(0x3d3cf08) SCALAR(0x3e12508)

sub { print \$_[0], \$_[1] }->( $n, $m );;
SCALAR(0x3d3cf08) SCALAR(0x3e12508)

##</code><code>##

sub { print \$_[0], \$_[1] }->( $n+1, $m+1 );;
SCALAR(0x3cc86d0) SCALAR(0x3d3f320)

##</code><code>##

[0] Perl> sub { print \$_[0], \$_[1]; +$_++ for @_ }->( $n+1, $m+1 );;
SCALAR(0x3cc86d0) SCALAR(0x3d3f320)
2 3 

##</code><code>##

print $n, $m;;
1 2