Completeness theorem for parse-wsp/vchar.
Theorem:
(defthm parse-wsp/vchar-when-tree-match (implies (and (tree-match-element-p tree (!_ (/_ *wsp*) (/_ *vchar*)) *grammar*) (tree-terminatedp tree)) (equal (parse-wsp/vchar (append (tree->string tree) rest-input)) (mv nil (tree-fix tree) (nat-list-fix rest-input)))))