Re: shift vs @_

[John SJ Anderson]

On Sunday, May 20, 2012 at 11:09 AM, sono...@fannullone.us wrote:
> Are there any differences between these two idioms if only one or zero 
> arguments are passed to them?
> 
> my ($mode) = @_;
> 
> my $mode = shift;
> 
> If so, why would you chose one over the other?
> 
> It seems to me that they behave exactly the same for this purpose, but maybe 
> there's a subtle difference that I'm not aware of.
'shift' will modify @_; assignment won't. Run this:

#! perl

use strict;
use warnings;
use feature 'say';

use Data::Printer;

sub shifter {
  my $var = shift;
  say "SHIFT";
  p $var;
  p @_;
  say '';
}

sub assigner {
  my( $var ) = @_;
  say "ASSIGN";
  p $var;
  p @_;
  say '';
}

shifter( 'foo' );
assigner( 'foo' );