You probably want to :depend-on (:fare-quasiquote-extras), which enables the named-readtable :fare-quasiquote and hooks for pattern-matching with optima.
Then in your file, you would
Note that ,@ probably only works well with pattern-matching when in final position, and that the pedantically correct syntax is `(foo . ,bar) whereas the former in a strict reading of the standard is required to (append ... nil) which optima won't recognize.
fare-quasiquote has a test suite with a lot of test cases that you can easily adapt and reuse to test your own implementation of quasiquote (useful for CL vendors, if they dare).
fare-quasiquote is written by Fare Rideau.
git clone https://gitlab.common-lisp.net/frideau/fare-quasiquote.git
Browse it at https://gitlab.common-lisp.net/frideau/fare-quasiquote
language extension utilities