That also works but you are incurring the expense of creating and invoking the subroutine for each and every element of the array rather than just once. This might have an impact on performance.

I think this benchmark code confirms my point regarding the expense of continually creating and invoking anonymous subroutines.

use strict;
use warnings;

use Benchmark qw{ cmpthese };

my @arr = ( 1 .. 1e6 );

my $rcOneElement  = sub
   {
       my $aref = shift;
       sub { my $var = shift }->( $_ ) for @$aref;
   };

my $rcAllElements = sub
   {
       my $aref = shift;
       sub { my $var = shift while @_ }->( @$aref );
   };

cmpthese (
   -5,
   {
       OneElement  => sub { $rcOneElement->( \ @arr ) },
       AllElements => sub { $rcAllElements->( \ @arr ) },
   }
   );
[download]

The output.

              Rate  OneElement AllElements
OneElement  2.59/s          --        -58%
AllElements 6.16/s        138%          --
[download]

However, I am good at cocking up benchmarks so I could be deluding myself :-/