brew gem allows you to install any rubygem as a homebrew formula.
It works by generating a stub formula for homebrew, which looks something like this:
class Ronn < Formula def initialize(*args) @name = "ronn" @version = "0.7.3" super end def install system "gem", "install", name, "--version", version, "--install-dir", prefix end end
This formula installs and unpacks all the dependencies under the Cellar path. So the package is completely self contained.
brew install brew-gem
brew gem heroku
Additionally, you may declare additional dependent gems that are specifically required by the original gem. For example, let's say you wanted to install capistrano and you need the capistrano-ext gem as well.
brew gem capistrano capistrano-ext
This is not for installing development libraries, but for standalone binary tools that you want system wide.