ruby-auto.el

ruby-auto is a Ruby environment auto-configuration tool for Emacs, inspired by the auto.sh functionality of Chruby.

This package requires having a .ruby-version file within the current buffer's directory tree.

Installation

Clone this repository:

git clone https://github.com/beelleau/ruby-auto.git

Either symlink or copy ruby-auto.el into a path that is loaded in your init.el. I typically use a symlink:

ln -s ruby-auto/ruby-auto.el .emacs.d/lisp/ruby-auto.el

Ensure your path is loaded, and load ruby-auto:

(add-to-list 'load-path
             (concat user-emacs-directory "lisp/"))

(require 'ruby-auto)

Usage

ruby-auto has one interactive function, also named ruby-auto.

You must have a .ruby-version file somewhere in the current buffer's directory tree. ruby-auto will find the nearest .ruby-version file.

Configuration

By default, ruby-auto will search for rubies in ~/.rubies. If you need to configure a different directory to search for rubies, you can modify the value of the ruby-auto-rubies-dir variable. Modify ruby-auto-rubies-dir after ruby-auto is loaded:

(require 'ruby-auto)
(setq ruby-auto-rubies-dir "/opt/rubies")

ruby-auto also uses a static gem directory configuration. By default, it will search for gems under ~/.gem. ruby-auto will automatically append the correct RUBY_ENGINE and RUBY_VERSION values to this variable to find the actual gem directory. If you need to configure a different directory to search for gems, you can modify the value of the ruby-auto-gem-dir variable. Modify ruby-auto-gem-dir after ruby-auto is loaded:

(require 'ruby-auto)
(setq ruby-auto-gem-dir "/usr/local/bundle")

If you use a configuration function to hook into major modes, you can have that function run the ruby-auto function. Run ruby-auto as early as possible in the function, since you'll likely want its configurations for other utilities like eglot, flymake, inf-ruby-minor-mode, etc.

;; a simple ruby-config function and hook
(defun ruby-config ()
  (ruby-auto)
  (visual-line-mode -1)
  (inf-ruby-minor-mode 1)
  (setq truncate-lines t
        fill-column 80
        ruby-indent-tabs-mode nil
        ruby-indent-level 2)
  (eglot-ensure)
  (corfu-mode 1))
(add-hook 'ruby-mode-hook #'ruby-config)

Lastly, you can run the ruby-auto function at any time to have your in-tree .ruby-version file discovered and environment variables set.

Acknowledgments

ruby-auto is inspired by Chruby written by postmodern. The methodology used to set environment variables in Chruby was influential in the methodology used in ruby-auto.el.