Get the fn field from a expr-gin.
This is an ordinary field accessor created by fty::defprod.
Function:
(defun expr-gin->fn$inline (x) (declare (xargs :guard (expr-ginp x))) (declare (xargs :guard t)) (let ((__function__ 'expr-gin->fn)) (declare (ignorable __function__)) (mbe :logic (b* ((x (and t x))) (symbol-fix (cdr (std::da-nth 3 x)))) :exec (cdr (std::da-nth 3 x)))))
Theorem:
(defthm symbolp-of-expr-gin->fn (b* ((fn (expr-gin->fn$inline x))) (symbolp fn)) :rule-classes :rewrite)
Theorem:
(defthm expr-gin->fn$inline-of-expr-gin-fix-x (equal (expr-gin->fn$inline (expr-gin-fix x)) (expr-gin->fn$inline x)))
Theorem:
(defthm expr-gin->fn$inline-expr-gin-equiv-congruence-on-x (implies (expr-gin-equiv x x-equiv) (equal (expr-gin->fn$inline x) (expr-gin->fn$inline x-equiv))) :rule-classes :congruence)