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Alternative

Alternativep

Recognizer for alternative structures.

Signature
(alternativep x) → *

Definitions and Theorems

Function: alternativep

(defun alternativep (x)
  (declare (xargs :guard t))
  (let ((__function__ 'alternativep))
    (declare (ignorable __function__))
    (and (mbe :logic (and (alistp x)
                          (equal (strip-cars x) '(name product)))
              :exec (fty::alist-with-carsp x '(name product)))
         (b* ((name (cdr (std::da-nth 0 x)))
              (product (cdr (std::da-nth 1 x))))
           (and (identifierp name)
                (type-productp product))))))

Theorem: consp-when-alternativep

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