Yacc2latex generates human-readable EBNF grammars from yacc files. Output format is in Latex and fairly customizable.
Distribution yacc2latex is available under LGLP licence (dowload here).
Goal As a language designer, I often faced the problem of writing and maintaining a reference (readable) grammar of my language. This is particularly annoying since the reference grammar actually exists as a yacc (or ocamlyacc) file, so why not use a “compiler” that will derived automaticaly the reference grammar from the yacc file ?