Homepage: https://www.gnu.org/software/emacs
Author: Michael Kifer
A full-featured Vi emulator for Emacs
Viper is a full-featured Vi emulator for Emacs. It emulates and improves upon the standard features of Vi and, at the same time, allows full access to all Emacs facilities. Viper supports multiple undo, file name completion, command, file, and search history and it extends Vi in many other ways. Viper is highly customizable through the various hooks, user variables, and keymaps. It is implemented as a collection of minor modes and it is designed to provide full access to all Emacs major and minor modes.