Get the element field from a array-type-class.
(array-type-class->element x) → element
This is an ordinary field accessor created by fty::defprod.
Function:
(defun array-type-class->element$inline (x) (declare (xargs :guard (array-typep x))) (declare (xargs :guard (equal (array-type-kind x) :class))) (let ((__function__ 'array-type-class->element)) (declare (ignorable __function__)) (mbe :logic (b* ((x (and (equal (array-type-kind x) :class) x))) (class-type-fix (std::da-nth 0 (cdr x)))) :exec (std::da-nth 0 (cdr x)))))
Theorem:
(defthm class-typep-of-array-type-class->element (b* ((element (array-type-class->element$inline x))) (class-typep element)) :rule-classes :rewrite)
Theorem:
(defthm array-type-class->element$inline-of-array-type-fix-x (equal (array-type-class->element$inline (array-type-fix x)) (array-type-class->element$inline x)))
Theorem:
(defthm array-type-class->element$inline-array-type-equiv-congruence-on-x (implies (array-type-equiv x x-equiv) (equal (array-type-class->element$inline x) (array-type-class->element$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm array-type-class->element-when-wrong-kind (implies (not (equal (array-type-kind x) :class)) (equal (array-type-class->element x) (class-type-fix nil))))