Gem metadata at your fingertips.
What's this for?
Sometimes it's useful to access information about a gem at runtime. Jewel exists to centralize access to that data and make it as easy as possible to access it.
How do I install it?
gem install jewel
git clone git://github.com/matheusmoreira/jewel.git
How do I use it?
Let's say you have a gem named
awesome. Let's define the
# lib/awesome/gem.rb require 'jewel' module Awesome class Gem < Jewel::Gem name! :awesome summary 'Awesome gem' version '1.2.3' homepage 'https://github.com/you/awesome' author 'You' email 'firstname.lastname@example.org' root '../..' # relative to this file's directory files `git ls-files`.split "\n" depend_on :jewel end end
Now you and others can access your specification at runtime. Let's use
it to set up the
#!/usr/bin/env gem build # encoding: utf-8 require './awesome/gem' Awesome::Gem.specification
bundler assume the
.gemspec returns a
Gem::Specification instance, which is exactly what is happening here.
External libraries? In my
.gemspec generators, Jewel will not duplicate information
and it will certainly not make a giant mess in your version control
system's diff. These are actually some of the reasons why I wrote this
However, you will probably run into problems if you use tools that parse
.gemspec or are unable to
require your gem. If that's your case,
then you'll be happy to know that you can also use your existing
# lib/awesome/gem.rb require 'jewel' module Awesome class Gem < Jewel::Gem root '../..' # specification is aliased as spec spec 'awesome.gemspec' end end
Hey, is that a
Rails.root-like method? Exactly! It basically returns a
dynamic Pathname allows you to join paths by chaining methods and
passing arguments to them:
root = Awesome::Gem.root root.lib.awesome 'gem.rb' # lib/awesome/gem.rb root.i18n I18n.locale.to_s, 'messages.yml' # i18n/en/messages.yml
Nifty. What else can it do?
It can make sure that the correct versions of your dependencies will be
loaded. When you
require some code, RubyGems will actually load the
latest version of the gem that it can find, even if you've specified a
lower version in the specification. To make it load the versions you
wanted, you can simply write:
Hey, it's broken!! Why doesn't it do this?
Found problems? Have ideas? The best way to get in touch is to create an issue on the GitHub tracker. Feel free to fork the repository send a pull request as well!