EIEIO

EIEIO (“Enhanced Implementation of Emacs Interpreted Objects”) provides an Object Oriented layer for Emacs Lisp, following the basic concepts of the Common Lisp Object System (CLOS). It provides a framework for writing object-oriented applications in Emacs.

This manual documents EIEIO, an object framework for Emacs Lisp.

Copyright © 2007–2025 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being “A GNU Manual,” and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License.”

(a) The FSF’s Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.”

Table of Contents

• 1 Quick Start

• 2 Introduction

• 3 Building Classes

  • 3.1 Inheritance
  • 3.2 Slot Options
  • 3.3 Class Options

• 4 Making New Objects

• 5 Accessing Slots

• 6 Writing Methods

• 7 Method Invocation

• 8 Predicates and Utilities

• 9 Association Lists

• 10 Customizing Objects

  • 10.1 Widget extension

• 11 Introspection

• 12 Base Classes

  • 12.1 eieio-instance-inheritor
  • 12.2 eieio-instance-tracker
  • 12.3 eieio-singleton
  • 12.4 eieio-persistent
  • 12.5 eieio-named
  • 12.6 eieio-speedbar

• 13 Browsing class trees

• 14 Class Values

• 15 Default Superclass

  • 15.1 Initialization
  • 15.2 Basic Methods
  • 15.3 Signal Handling

• 16 Signals

• 17 Naming Conventions

• 18 CLOS compatibility

• 19 Wish List

• Appendix A GNU Free Documentation License

• Function Index