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