Check if an optional token may start a designator.
(token-designator-start-p token?) → yes/no
A designator starts with an open square bracket or a dot.
Function:
(defun token-designator-start-p (token?) (declare (xargs :guard (token-optionp token?))) (let ((__function__ 'token-designator-start-p)) (declare (ignorable __function__)) (or (token-punctuatorp token? "[") (token-punctuatorp token? "."))))
Theorem:
(defthm booleanp-of-token-designator-start-p (b* ((yes/no (token-designator-start-p token?))) (booleanp yes/no)) :rule-classes :rewrite)
Theorem:
(defthm non-nil-when-token-designator-start-p (implies (token-designator-start-p token?) token?) :rule-classes :compound-recognizer)