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Representation-of-integers

Scharp

Recognizer of values of type signed char.

Signature
(scharp x) → yes/no
Returns: yes/no — Type (booleanp yes/no).

Definitions and Theorems

Function: scharp

(defun scharp (x)
  (declare (xargs :guard t))
  (let ((__function__ 'scharp))
    (declare (ignorable __function__))
    (and (consp x)
         (eq (car x) :schar)
         (true-listp (cdr x))
         (eql (len (cdr x)) 1)
         (b* ((get (std::da-nth 0 (cdr x))))
           (schar-integerp get)))))

Theorem: booleanp-of-scharp

(defthm booleanp-of-scharp
  (b* ((yes/no (scharp x)))
    (booleanp yes/no))
  :rule-classes :rewrite)

Theorem: consp-when-scharp

(defthm consp-when-scharp
  (implies (scharp x) (consp x))
  :rule-classes :compound-recognizer)