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Character-kinds

Nondigit-char-p

Recognize characters that are not decimal digits.

Definitions and Theorems

Function: nondigit-char-p

(defun nondigit-char-p (x)
  (declare (xargs :guard t))
  (and (characterp x)
       (b* ((code (char-code x)))
         (not (and (<= (char-code #\0) code)
                   (<= code (char-code #\9)))))))

Theorem: booleanp-of-nondigit-char-p

(defthm booleanp-of-nondigit-char-p
  (booleanp (nondigit-char-p x))
  :rule-classes :type-prescription)

Theorem: characterp-when-nondigit-char-p

(defthm characterp-when-nondigit-char-p
  (implies (nondigit-char-p x)
           (characterp x))
  :rule-classes :compound-recognizer)

Subtopics

Nondigit-charlist-p: (nondigit-charlist-p x) recognizes lists where every element satisfies nondigit-char-p.
Nondigit-chars: A character set for nondigit-char-p.