                      prod_part_list
prod_part_list     ::= prod_part_list prod_part | empty
prod_part          ::= symbol_id opt_label | CODE_STRING
opt_label          ::= COLON label_id | empty
multipart_id       ::= multipart_id DOT ID | ID
import_id          ::= multipart_id DOT STAR | multipart_id
type_id            ::= multipart_id
terminal_id        ::= term_id
term_id            ::= symbol_id
new_term_id        ::= ID
new_non_term_id    ::= ID
nt_id              ::= ID
symbol_id          ::= ID
labe