contiguous-numeric-set-type

contiguous-numeric-set-type.lisp

(defun contiguous-numeric-set-type (xset)
  (let ((members (xset-members xset)))
    (cond ((null members)
           nil)
          ((null (cdr members))
           (ctype-of (car members)))
          ;; Is MEMBERS a contiguous integer range?
          ((loop for x in members
                 always (integerp x)
                 minimizing x into min
                 maximizing x into max
                 finally (return (when (= (- max min)
                                          (1- (length members)))
                                   (make-numeric-type :class 'integer
                                                      :low min :high max)))))
          ;; It's useful to know when something is not zero
          ((xset-member-p 0 xset)
           (make-numeric-type :class 'integer :low 0 :high 0)))))

contiguous-numeric-set-type2.lisp

(defun contiguous-numeric-set-type (xset)
  (cond ((xset-empty-p xset)
         nil)
        ;; Is MEMBERS a contiguous integer range?
        ((block nil
           (let ((count 0)
                 (min nil)
                 (max nil))
             (declare (type fixnum count))
             (map-xset (lambda (value)
                         (unless (integerp value)
                           (return))
                         (incf count)
                         (when (or (null min) (< value min))
                           (setf min value))
                         (when (or (null max) (> value max))
                           (setf max value)))
                       xset)
             (when (= (- max min) (1- count))
               (make-numeric-type :class 'integer
                                  :low min :high max)))))
        ;; It's useful to know when something is not zero
        ((xset-member-p 0 xset)
         (make-numeric-type :class 'integer :low 0 :high 0))))