;;; -*- lexical-binding: t -*-
(require 'eieio)
(require 'eieio-base)

(defclass person ()
  ((name :type string :initarg :name)))

(defclass classy (eieio-persistent)
  ((teacher
    :type person
    :initarg :teacher)
   (students
    :initarg :students :initform (make-hash-table :test 'equal))))

(let* ((jane (make-instance 'person :name "Jane"))
       (bob  (make-instance 'person :name "Bob"))
       (class (make-instance 'classy
			     :teacher jane
			     :file (concat "classy-" emacs-version ".eieio"))))
  (puthash "Bob" bob (slot-value class 'students))
  (eieio-persistent-save class (concat "classy-" emacs-version ".eieio"))
  (eieio-persistent-read (concat "classy-" emacs-version ".eieio") 'classy t))