Fixer for unicode.
Function:
(defun unicode-fix (x) (declare (xargs :guard (unicodep x))) (mbe :logic (if (unicodep x) x 0) :exec x))
Theorem:
(defthm unicodep-of-unicode-fix (b* ((fixed-x (unicode-fix x))) (unicodep fixed-x)) :rule-classes :rewrite)
Theorem:
(defthm unicode-fix-when-unicodep (implies (unicodep x) (equal (unicode-fix x) x)))