This is an extended version of cl-yacc, that brings syntax for [optionals[], {repeats}, and alternates "|"
You can use these in productions using the following syntax
(:+ ... 'action) one or more repetitions
(:* ... 'action) zero or more repetitions
(:? ... 'action) optional - can be present or not
(:or ... 'action) alternatives. Usual notation is pipe but we can't comfortably use that in lisp.
To load and test the development version in org syntax.
(asdf::load-system :yacc+)
(asdf:test-system :yacc+)
Or you can use the older sysdef to avoid external dependencies.
(asdf:load-system :yacc)
(compile-file "yacc-tests.lisp")
(load *)
(yacc-tests:tests)
Note that you really must compile yacc-tests.lisp to a file in order to
test the fasdumping machinery.
Documentation is provided in texinfo format in ``cl-yacc.texi'' and in yacc+.org.
You will find a complete example in the file ``calculator.lisp''.
Credit to Juliusz Chroboczek whose github repository https://github.com/jech/cl-yacc I forked.