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Dec-expo

Dec-expop

Recognizer for dec-expo structures.

Signature
(dec-expop x) → *

Definitions and Theorems

Function: dec-expop

(defun dec-expop (x)
 (declare (xargs :guard t))
 (let ((__function__ 'dec-expop))
   (declare (ignorable __function__))
   (and (mbe :logic (and (alistp x)
                         (equal (strip-cars x)
                                '(prefix sign? digits)))
             :exec (fty::alist-with-carsp x '(prefix sign? digits)))
        (b* ((prefix (cdr (std::da-nth 0 x)))
             (sign? (cdr (std::da-nth 1 x)))
             (digits (cdr (std::da-nth 2 x))))
          (and (dec-expo-prefixp prefix)
               (sign-optionp sign?)
               (dec-digit-char-listp digits))))))

Theorem: consp-when-dec-expop

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