Get the index field from a expression-component.
(expression-component->index x) → index
This is an ordinary field accessor created by fty::defprod.
Function:
(defun expression-component->index$inline (x) (declare (xargs :guard (expressionp x))) (declare (xargs :guard (equal (expression-kind x) :component))) (let ((__function__ 'expression-component->index)) (declare (ignorable __function__)) (mbe :logic (b* ((x (and (equal (expression-kind x) :component) x))) (nfix (std::da-nth 1 (cdr x)))) :exec (std::da-nth 1 (cdr x)))))
Theorem:
(defthm natp-of-expression-component->index (b* ((index (expression-component->index$inline x))) (natp index)) :rule-classes :rewrite)
Theorem:
(defthm expression-component->index$inline-of-expression-fix-x (equal (expression-component->index$inline (expression-fix x)) (expression-component->index$inline x)))
Theorem:
(defthm expression-component->index$inline-expression-equiv-congruence-on-x (implies (expression-equiv x x-equiv) (equal (expression-component->index$inline x) (expression-component->index$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm expression-component->index-when-wrong-kind (implies (not (equal (expression-kind x) :component)) (equal (expression-component->index x) (nfix nil))))