Given a list such as
(list "foo" "bar" nil "moo" "bar" "moo" nil "affe")
how would I build a new list with the duplicate strings removed, as well as the nils stripped, i.e.
(list "foo" "bar" "moo" "affe")
The order of the elements needs to be preserved - the first occurence of a string may not be removed.
The lists I'm dealing with here are short, so there's no need to use anything like a hash table for the uniqueness check, although doing so certainly wouldn't hurt either. However, using cl functionality is not a viable option.