If you are looking for an alternative to standard parser generators you may wish to have a peek at Chevrotain. * https://github.com/SAP/chevrotain

Instead of using an abstraction of a declarative grammar definition and code generation to provide an alternative to writing a parser by hand, Chevrotain simplifies the process of hand crafting a parser.

Meaning no code generation and you can still directly debug the code you have written (unlike most parser combinators).