Hyacc is an efficient and practical Yacc/Bison-compatible full LR(1)/LALR(1)/LR(0) and partial LR(k) parser generator in ANSI C based on Knuth and Pager's LR(1) algorithms. Generated parser can be used in open-source or commercial software.
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...