竜 TatSu v4.4.0 has been released. Thanks to Vic Nightfall, support for left-recursion in PEG grammars is now complete.
def WARNING(): return 'v4.4.0 is the last version of 竜TatSu supporting Python 2.7'
竜 TatSu (the successor to Grako) is a tool that takes grammars in a variation of EBNF as input, and outputs memoizing (Packrat) PEG parsers in Python.
竜 TatSu can compile a grammar stored in a string into a tatsu.grammars.Grammar object that can be used to parse any given input, much like the re module does with regular expressions, or it can generate a Python module that implements the parser.
竜 TatSu supports left-recursive rules in PEG grammars using the algorithm by _Laurent_ and _Mens_. The generated AST has the expected left associativity.
-- Juancarlo Añez