Styx is a scanner and parser generator designed to address some shortcomings of the traditional lex/yacc combination.
It has unique features like automatic derivation of depth grammar, production of the derivation tree including it's C interface which provides access to the abstract syntax tree, preservation of full source information and pretty printing to facilitate source-source translation, persistence to aid rapid interpreter writing.
For application in contemporary computing environments, it supports unicode, reentrancy and offers thread-safeness.