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Pointer

Pointerp

Recognizer for pointer structures.

Signature
(pointerp x) → *

Definitions and Theorems

Function: pointerp

(defun pointerp (x)
  (declare (xargs :guard t))
  (let ((__function__ 'pointerp))
    (declare (ignorable __function__))
    (and (consp x)
         (cond ((or (atom x) (eq (car x) :null))
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :dangling)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               (t (and (eq (car x) :valid)
                       (and (true-listp (cdr x))
                            (eql (len (cdr x)) 1))
                       (b* ((get (std::da-nth 0 (cdr x))))
                         (objdesignp get))))))))

Theorem: consp-when-pointerp

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