LEX is essentially a boilerplate generator for Ragel. Ragel is an immensely useful and highly performant parser generator for regular languages. If your grammar can be parsed with a regex, Ragel alone can manage that. For an example, see the URI parser. The typical use though is to use Ragel as a lexer tokenizing the byte stream. The higher-level parser is built on top of that. For an example, see the JSON parser.
As of now, LEX supports C and Go.