sub build_list {
   my $item = shift;
   my $list = shift || [];
   unshift(@$list, $item);
   return $list;
}


{ # Without parens:
   my $list = build_list 'a', build_list 'b', build_list 'c';
   print(@$list, "\n");  # abc
}

{ # With parens:
   my $list = build_list('a', build_list('b', build_list('c')));
   print(@$list, "\n");  # abc
}

{ # Spelled out:
   my $list;
   $list = build_list 'c';
   $list = build_list 'b', $list;
   $list = build_list 'a', $list;
   print(@$list, "\n");  # abc
}