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• Downcase-string

Downcase-string-aux

Signature

(downcase-string-aux x n xl acc) → *

Arguments

x — Guard (stringp x).

n — Guard (natp n).

xl — Guard (eql xl (length x)).

Definitions and Theorems

Function: downcase-string-aux

(defun downcase-string-aux (x n xl acc)
  (declare (type string x)
           (type (integer 0 *) n)
           (type (integer 0 *) xl))
  (declare (xargs :guard (and (stringp x)
                              (natp n)
                              (eql xl (length x)))))
  (declare (xargs :split-types t :guard (<= n xl)))
  (let ((acl2::__function__ 'downcase-string-aux))
    (declare (ignorable acl2::__function__))
    (mbe :logic
         (revappend (downcase-charlist (nthcdr n (explode x)))
                    acc)
         :exec
         (if (eql n xl)
             acc
           (let* ((char (char x n))
                  (downchar (downcase-char char)))
             (downcase-string-aux x (+ 1 n)
                                  xl (cons downchar acc)))))))