Packages to define grammar for language in Emacs

For instance I wanna validate some file with a custom format. Are there libraries to define format and produce human readable errors when it's violated? To be more concrete, libraries which accepts some file describing language syntax and producing ELisp based parser for it. By all means I can handle format without such libraries but I don't know whether it's the best decision in Emacs world.

There's `peg.el` and Emacs's builtin semantic bovinator. https://github.com/emacsmirror/peg

Thanks! I'll give it a try. :)