Recognizer for booleans
(Booleanp x) is t if x is t or nil, and is
See generalized-booleans for a discussion of a potential soundness
problem for ACL2 related to the question: Which Common Lisp functions are
known to return Boolean values?
(defun booleanp (x)
(declare (xargs :guard t))
(if (eq x t) t (eq x nil)))
- Recognizer for a true list of booleans
- (bool-fix x) is a fixing function for Booleans; it coerces any
non-nil symbol to t.