#1
while (@array) {
  my $elem = shift @array;
  ...
}

#2
foo(@array);
...
sub foo {
  my $elem = shift;
  ...
  foo(@_) if @_;
  ...
}

#3
foo(@array);
...
sub foo {
  my $elem = shift;
  ...
  &foo if @_;
  ...
}

#4
{
  my $elem = shift @array;
  ...
  redo if @array;
}