Get the position field from a char+position.
(char+position->position x) → position
This is an ordinary field accessor created by fty::defprod.
Function:
(defun char+position->position$inline (x) (declare (xargs :guard (char+position-p x))) (declare (xargs :guard t)) (let ((__function__ 'char+position->position)) (declare (ignorable __function__)) (mbe :logic (b* ((x (and t x))) (position-fix (cdr (std::da-nth 1 x)))) :exec (cdr (std::da-nth 1 x)))))
Theorem:
(defthm positionp-of-char+position->position (b* ((position (char+position->position$inline x))) (positionp position)) :rule-classes :rewrite)
Theorem:
(defthm char+position->position$inline-of-char+position-fix-x (equal (char+position->position$inline (char+position-fix x)) (char+position->position$inline x)))
Theorem:
(defthm char+position->position$inline-char+position-equiv-congruence-on-x (implies (char+position-equiv x x-equiv) (equal (char+position->position$inline x) (char+position->position$inline x-equiv))) :rule-classes :congruence)