Input decomposition theorem for parse-rule-/-*cwsp-cnl.
Theorem:
(defthm input-decomposition-of-parse-rule-/-*cwsp-cnl (b* (((mv error? tree? rest-input) (parse-rule-/-*cwsp-cnl input))) (implies (not error?) (equal (append (tree->string tree?) rest-input) (nat-list-fix input)))))