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