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Decdig/uscore

Decdig/uscore-p

Recognizer for decdig/uscore structures.

Signature
(decdig/uscore-p x) → *

Definitions and Theorems

Function: decdig/uscore-p

(defun decdig/uscore-p (x)
  (declare (xargs :guard t))
  (let ((__function__ 'decdig/uscore-p))
    (declare (ignorable __function__))
    (and (consp x)
         (cond ((or (atom x) (eq (car x) :digit))
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 1)
                     (b* ((get (std::da-nth 0 (cdr x))))
                       (dec-digitp get))))
               (t (and (eq (car x) :underscore)
                       (and (true-listp (cdr x))
                            (eql (len (cdr x)) 0))
                       (b* nil t)))))))

Theorem: consp-when-decdig/uscore-p

(defthm consp-when-decdig/uscore-p
  (implies (decdig/uscore-p x) (consp x))
  :rule-classes :compound-recognizer)