		Search-engine friendly clone of the ACL2 documentation.

Vl-special

Vl-specialkey-p

This is an ordinary defenum.

Function: vl-specialkey-p

(defun vl-specialkey-p (x)
  (declare (xargs :guard t))
  (or (eq x ':vl-null)
      (eq x ':vl-$)
      (eq x ':vl-emptyqueue)
      (eq x ':vl-1step)))

Theorem: type-when-vl-specialkey-p

(defthm type-when-vl-specialkey-p
  (implies (vl-specialkey-p x)
           (if (symbolp x)
               (if (not (equal x 't))
                   (not (equal x 'nil))
                 'nil)
             'nil))
  :rule-classes :compound-recognizer)