Try this: my ($self, @$objs) = @_;

This doesn't work either. There are two ways to do this, depending on how you want to call the subroutine - and disregarding for the moment that this is supposedly a method of an object.

# (1) call with a reference to an array
my $ref = [1,2,3];
foo(1,$ref);

sub foo {
  my ($self, $aref) = @_;

  # change the element in $ref
  $aref->[0] = 3;

  # make a copy
  my @array = @$aref;
  $array[0] = 3;
}


########################################
# (2) or call with an array of values
my @arr = (1,2,3);
foo(1,@arr);

sub foo {
  my ($self, @array) = @_;

  # @array is already a copy
  $array[0] = 3;
}
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A totally different problem is the deep copying of objects. This depends very heavily on the object being copied and cannot be done correctly in a general way. The reason for this is that some parts of the object might have to be duplicated normally, but some might have to be treated in a special way (think e.g. of IO objects connected to files) that depends on the purpose and implementation of the object itself.

There should be a method of the object giving back a deep copy. Only this method can handle the operation correctly for the corresponding object.

-- Hofmator