What's the benefit of shifting @_ for argument passing in Perl?

Question

sub foo {
 $arg1 = shift @_;
 $arg2 = shift @_;
 # ...
}

What's the benefit of this idiom? I see only disadvantages compared to explicitly working with $_[0], $_[1], ... The array has to be shifted, which is time consuming. It is destroyed, so that at a later point in time, the arguments have vanished (sad if you need them again and have overwritten your $arg1 with a different value).

Answer 1

Shifting @_ is common in OO perl so parameters can be separated from instance of the class which is automatically added as first element of @_.

It can also be used to write less when assigning default values for input parameters, although personally I don't find it appealing,

sub foo {
  my $arg1 = shift // 2;
  my $arg2 = shift // 7;
  # ...
}

I see only disadvantages compared to explicitly working with $[0], $1, ...

Instead of working with $_[0], $_[1], assigning whole @_ array at once is better/less error prone/more readable practice.

my ($arg1, $arg2) = @_;

Also note that @_ elements are aliased to passed variables, so accidental changes could happen,

sub foo {
  $_[0] = 33;
  $_[1] = 44;
}

my ($x, $y) = (11,22);

print "($x, $y)\n";
foo($x, $y);
print "($x, $y)\n";

output

(11, 22)
(33, 44)