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(in-package #:cursed)

(defclass text ()
  ((data :type simple-string :initarg :data :reader data :initform "")
   (index :type (unsigned-byte 44) :initarg :index :accessor index :initform 0)))

(defun has-data? (cursor)
  (< (index cursor) (length (data cursor))))

(defun peek (cursor)
  (char (data cursor)
        (index cursor)))

(defun advance (cursor)
  (make-instance 'text
                 :data (data cursor)
                 :index (+ (index cursor) 1)))

(defun distance (from to)
  (- (index to)
     (index from)))

(defmethod print-object ((obj text) stream)
  (print-unreadable-object (obj stream :type t)
    (let ((str (if (has-data? obj)
                 (format nil "~{~a~a~a~}"
                         (str:context-window (data obj)
                                             (index obj)
                                             :side-length 10))
                 "END OF DATA")))
      (substitute #\↲ #\Newline str))))