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Primitive-functions

Eval-code-char

Evaluation semantics of code-char.

Signature
(eval-code-char x) → result
Arguments: x — Guard (valuep x).
Returns: result — Type (valuep result).

Definitions and Theorems

Function: eval-code-char

(defun eval-code-char (x)
  (declare (xargs :guard (valuep x)))
  (let ((__function__ 'eval-code-char))
    (declare (ignorable __function__))
    (value-character
         (if (value-case-integer x)
             (b* ((x-integer (value-integer->get x)))
               (if (and (>= x-integer 0) (< x-integer 256))
                   (code-char x-integer)
                 (code-char 0)))
           (code-char 0)))))

Theorem: valuep-of-eval-code-char

(defthm valuep-of-eval-code-char
  (b* ((result (eval-code-char x)))
    (valuep result))
  :rule-classes :rewrite)

Theorem: eval-code-char-of-value-fix-x

(defthm eval-code-char-of-value-fix-x
  (equal (eval-code-char (value-fix x))
         (eval-code-char x)))

Theorem: eval-code-char-value-equiv-congruence-on-x

(defthm eval-code-char-value-equiv-congruence-on-x
  (implies (value-equiv x x-equiv)
           (equal (eval-code-char x)
                  (eval-code-char x-equiv)))
  :rule-classes :congruence)