Emacs and rbenv
When writing ruby code, you need a tool to manage your ruby versions as well all the gem you need to have installed. In this post I'll show you some of the advantages of using rbenv if you are using emacs.
TLDR: Scroll down and copy past the elisp code into your
use rbenv. That's all you need.
The best tools in a developer tool belt stay out of our way. rvm does exactly the opposite, it tries to do too much, handling gemsets, installing ruby versions, managing installed gems, etc.
chruby seems like it tries to do the right thing, doing one thing well, but unfortunately it doesn't integrate very well with emacs.
When using chruby, you need to invoke a
chruby <ruby version>
command in your shell before invoking
gem, or any other
command that uses ruby.
Emacs usually uses it's
creation functions to run commands like flymake or when you run
rspec in a
*Compilation* buffer. This means that before you can
execute a ruby process, you always need to call
chruby <version> so
that chruby can set all the required environment variables before
your ruby process is executed.
This is not easy to manage since every emacs mode can have a different
way of invoking shell commands. You could use
chruby.el or something similar,
but this means that all your emacs modes need to be aware of
chruby.el, or you need tome automatic way to call the
API everytime you run a ruby subprocess.
But we don't need this complexity if the right environment variables
and settings are always in your
PATH when emacs starts a shell
to execute some command.
Enter rbenv. If you make sure that emacs has rbenv's shims path in
PATH everytime it starts a new command, then you don't need to worry
if emacs selects the right ruby version before running your
command. rbenv will do the right thing and setup all the required
environment variables for you.
This means that all you need in emacs to run rbenv is the following two lines:
(setenv "PATH" (concat (getenv "HOME") "/.rbenv/shims:" (getenv "HOME") "/.rbenv/bin:" (getenv "PATH"))) (setq exec-path (cons (concat (getenv "HOME") "/.rbenv/shims") (cons (concat (getenv "HOME") "/.rbenv/bin") exec-path)))
This guarantees that everytime a subprocess command is used in emacs,
rbenv's shims will be in your
PATH and you don't have to worry about
calling any other commands before invoking ruby commands from
emacs. flymake and other common emacs modes will work without any
It's this simple, to use rbenv with emacs you just need these lines
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