Recognizer for feat structures.
(featp x) → *
Function:
(defun featp (x) (declare (xargs :guard t)) (let ((__function__ 'featp)) (declare (ignorable __function__)) (and (mbe :logic (and (alistp x) (equal (strip-cars x) '(bits))) :exec (fty::alist-with-carsp x '(bits))) (b* ((bits (cdr (std::da-nth 0 x)))) (feat-bitsp bits)))))
Theorem:
(defthm consp-when-featp (implies (featp x) (consp x)) :rule-classes :compound-recognizer)