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Scalar-operations

Test-scalar-value

Test a scalar value logically.

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

In some contexts (e.g. conditional tests), a scalar is treated as a logical boolean: false if 0 (i.e. null if a pointer), true if not 0 (i.e. not null if a pointer). This is captured by this ACL2 function.

Definitions and Theorems

Function: test-scalar-value

(defun test-scalar-value (val)
  (declare (xargs :guard (valuep val)))
  (declare (xargs :guard (value-scalarp val)))
  (let ((__function__ 'test-scalar-value))
    (declare (ignorable __function__))
    (cond ((value-integerp val)
           (test-integer-value val))
          ((value-case val :pointer)
           (test-pointer-value val))
          (t (ec-call (acl2::bool-fix (impossible)))))))

Theorem: booleanp-of-test-scalar-value

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

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

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

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

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