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Message-utilities

Maybe-msgp

Recognize nil and messages.

Signature
(maybe-msgp x) → yes/no
Returns: yes/no — Type (booleanp yes/no).

Definitions and Theorems

Function: maybe-msgp

(defun maybe-msgp (x)
  (declare (xargs :guard t))
  (let ((__function__ 'maybe-msgp))
    (declare (ignorable __function__))
    (or (msgp x) (null x))))

Theorem: booleanp-of-maybe-msgp

(defthm booleanp-of-maybe-msgp
  (b* ((yes/no (maybe-msgp x)))
    (booleanp yes/no))
  :rule-classes :rewrite)

Theorem: maybe-msgp-when-msgp

(defthm maybe-msgp-when-msgp
  (implies (msgp x) (maybe-msgp x)))

Theorem: maybe-msgp-of-nil

(defthm maybe-msgp-of-nil
  (maybe-msgp nil))