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Escape

Escapep

Recognizer for escape structures.

Signature
(escapep x) → *

Definitions and Theorems

Function: escapep

(defun escapep (x)
  (declare (xargs :guard t))
  (let ((__function__ 'escapep))
    (declare (ignorable __function__))
    (and (consp x)
         (cond ((or (atom x) (eq (car x) :simple))
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 1)
                     (b* ((unwrap (std::da-nth 0 (cdr x))))
                       (simple-escapep unwrap))))
               ((eq (car x) :oct)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 1)
                     (b* ((unwrap (std::da-nth 0 (cdr x))))
                       (oct-escapep unwrap))))
               ((eq (car x) :hex)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 1)
                     (b* ((unwrap (std::da-nth 0 (cdr x))))
                       (hex-digit-char-listp unwrap))))
               (t (and (eq (car x) :univ)
                       (and (true-listp (cdr x))
                            (eql (len (cdr x)) 1))
                       (b* ((unwrap (std::da-nth 0 (cdr x))))
                         (univ-char-name-p unwrap))))))))

Theorem: consp-when-escapep

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