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• Fty::basetypes
• Maybe-integerp

Maybe-integerp-fix

(maybe-integerp-fix x) is the identity for maybe-integerps, or coerces any invalid object to nil.

Performance note. In the execution this is just an inlined identity function, i.e., it should have zero runtime cost.

Definitions and Theorems

Function: maybe-integerp-fix$inline

(defun maybe-integerp-fix$inline (x)
  (declare (xargs :guard (maybe-integerp x)))
  (mbe :logic (if x (ifix x) nil)
       :exec x))

Theorem: maybe-integerp-of-maybe-integerp-fix

(defthm maybe-integerp-of-maybe-integerp-fix
  (maybe-integerp (maybe-integerp-fix x))
  :rule-classes (:rewrite :type-prescription))

Theorem: maybe-integerp-fix-when-maybe-integerp

(defthm maybe-integerp-fix-when-maybe-integerp
  (implies (maybe-integerp x)
           (equal (maybe-integerp-fix x) x)))

Theorem: maybe-integerp-fix-under-iff

(defthm maybe-integerp-fix-under-iff
  (iff (maybe-integerp-fix x) x))

Theorem: maybe-integerp-fix-under-int-equiv

(defthm maybe-integerp-fix-under-int-equiv
  (int-equiv (maybe-integerp-fix x) x))