		Search-engine friendly clone of the ACL2 documentation.

Pointer-operations

Test-pointer-value

Test a pointer value logically.

Signature
(test-pointer-value val) → res
Arguments: val — Guard (valuep val).
Returns: res — Type (booleanp res).

In some contexts (e.g. conditional tests), a pointer is treated as a logical boolean: false if null, true if not null. This is captured by this ACL2 function.

Definitions and Theorems

Function: test-pointer-value

(defun test-pointer-value (val)
  (declare (xargs :guard (valuep val)))
  (declare (xargs :guard (value-case val :pointer)))
  (let ((__function__ 'test-pointer-value))
    (declare (ignorable __function__))
    (not (value-pointer-nullp val))))

Theorem: booleanp-of-test-pointer-value

(defthm booleanp-of-test-pointer-value
  (b* ((res (test-pointer-value val)))
    (booleanp res))
  :rule-classes :rewrite)

Theorem: test-pointer-value-of-value-fix-val

(defthm test-pointer-value-of-value-fix-val
  (equal (test-pointer-value (value-fix val))
         (test-pointer-value val)))

Theorem: test-pointer-value-value-equiv-congruence-on-val

(defthm test-pointer-value-value-equiv-congruence-on-val
  (implies (value-equiv val val-equiv)
           (equal (test-pointer-value val)
                  (test-pointer-value val-equiv)))
  :rule-classes :congruence)