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Error-checking

Ensure-tuple

Cause an error if a value is not a tuple of a given length.

Signature
(ensure-tuple x n description error-erp error-val ctx state) → (mv erp val state)
Arguments: x — Value to check.; n — Length that x must have.
Guard (natp n).; description — Guard (msgp description).; error-erp — Flag to return in case of error.; error-val — Value to return in case of error.; ctx — Context for errors.
Returns: erp — Type (implies erp (equal erp error-erp)).; val — Type (and (implies erp (equal val error-val)) (implies (and (not erp) error-erp) (not val))) .

Definitions and Theorems

Function: ensure-tuple

(defun ensure-tuple (x n description
                       error-erp error-val ctx state)
  (declare (xargs :stobjs (state)))
  (declare (xargs :guard (and (natp n) (msgp description))))
  (b*
    (((unless (tuplep n x))
      (er-soft+ ctx error-erp error-val
                "~@0 must be a NIL-terminated list of ~x1 elements."
                description n)))
    (value nil)))

Theorem: return-type-of-ensure-tuple.erp

(defthm return-type-of-ensure-tuple.erp
  (b* (((mv ?erp ?val ?state)
        (ensure-tuple x n description
                      error-erp error-val ctx state)))
    (implies erp (equal erp error-erp)))
  :rule-classes :rewrite)

Theorem: return-type-of-ensure-tuple.val

(defthm return-type-of-ensure-tuple.val
  (b* (((mv ?erp ?val ?state)
        (ensure-tuple x n description
                      error-erp error-val ctx state)))
    (and (implies erp (equal val error-val))
         (implies (and (not erp) error-erp)
                  (not val))))
  :rule-classes :rewrite)

Subtopics

Ensure-tuple$: Calls ensure-tuple with ctx and state as the last two arguments.