		Search-engine friendly clone of the ACL2 documentation.

Mode

Modep

Recognizer for mode structures.

Signature
(modep x) → *

Definitions and Theorems

Function: modep

(defun modep (x)
  (declare (xargs :guard t))
  (let ((__function__ 'modep))
    (declare (ignorable __function__))
    (and (consp x)
         (cond ((or (atom x) (eq (car x) :regular))
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :break)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :continue)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               (t (and (eq (car x) :leave)
                       (and (true-listp (cdr x))
                            (eql (len (cdr x)) 0))
                       (b* nil t)))))))

Theorem: consp-when-modep

(defthm consp-when-modep
  (implies (modep x) (consp x))
  :rule-classes :compound-recognizer)