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Tag-info

Tag-infop

Recognizer for tag-info structures.

Signature
(tag-infop x) → *

Definitions and Theorems

Function: tag-infop

(defun tag-infop (x)
  (declare (xargs :guard t))
  (and (consp x)
       (cond ((or (atom x) (eq (car x) :struct))
              (and (true-listp (cdr x))
                   (eql (len (cdr x)) 1)
                   (b* ((members (std::da-nth 0 (cdr x))))
                     (member-type-listp members))))
             ((eq (car x) :union)
              (and (true-listp (cdr x))
                   (eql (len (cdr x)) 0)
                   (b* nil t)))
             (t (and (eq (car x) :enum)
                     (and (true-listp (cdr x))
                          (eql (len (cdr x)) 0))
                     (b* nil t))))))

Theorem: consp-when-tag-infop

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