Check if an optional token is a preincrement or predecrement operator.
(token-preinc/predec-operator-p token?) → yes/no
Function:
(defun token-preinc/predec-operator-p (token?) (declare (xargs :guard (token-optionp token?))) (let ((__function__ 'token-preinc/predec-operator-p)) (declare (ignorable __function__)) (or (token-punctuatorp token? "++") (token-punctuatorp token? "--"))))
Theorem:
(defthm booleanp-of-token-preinc/predec-operator-p (b* ((yes/no (token-preinc/predec-operator-p token?))) (booleanp yes/no)) :rule-classes :rewrite)
Theorem:
(defthm non-nil-when-token-preinc/predec-operator-p (implies (token-preinc/predec-operator-p token?) token?) :rule-classes :compound-recognizer)