This course will be retired on June 1, 2025.

Heads up! To view this whole video, sign in with your Courses account or enroll in your free 7-day trial. Sign In Enroll

Ruby Gems

Preview

Start a free Courses trial
to watch this video

Sign up for Treehouse

Gem Content

3:30 with Jason Seifer

Occasionally, you may want to know how a gem functions internally. In this video, we'll see how to look at the contents of a gem.

This video doesn't have any notes.

Related Discussions

Have questions about this video? Start a discussion with the community and Treehouse staff.

Sign up

    Related Discussions

    Have questions about this video? Start a discussion with the community and Treehouse staff.

    Sign up

    Sometimes, as you're coding and using a gem, you may want to get a better idea 0:00
    of how it was written or take a look at a function or method. 0:05
    RubyGems gives us this ability with a couple of different commands. 0:09
    We can see the location of gems and open them in our editor to see how they work. 0:13
    Let's go ahead and see how that works now using Workspaces. 0:18
    So if we want to see the contents of a gem, we can use the contents command. 0:22
    And we pass in the name of the gem. 0:27
    So by typing, gem contents money, 0:31
    this will list everything that is inside of the money gem. 0:34
    These are all of the different files. 0:38
    Authors, change log, contributing, gem file, etc. 0:40
    We can also see all the library files that make up the money gem. 0:45
    The gemspec, which tells Ruby about the different versions and 0:50
    dependencies, and the different tests. 0:55
    Let's go ahead and change to that directory. 1:00
    So we can do that by saying, 1:04
    cd /home/treehouse/.local/gems/gems/money-6.- 1:06
    6.1. 1:15
    And now we are inside of the money gem. 1:16
    If we wanted to get a list of how this works, we could use the ls command, 1:23
    and we can see that the only file listed is money.rb. 1:29
    Which requires everything from this directory inside of the money directory. 1:34
    So if we go a little bit further and 1:41
    we list the files, we should see that these should be included as well. 1:43
    So we require money/money and money/currency. 1:48
    So if I look at the money.rb file, 1:56
    here is the different Ruby code that makes up the Ruby money gem. 2:00
    Now, if we do some syntax highlighting here with vim, 2:12
    we can walk through the money class, and 2:17
    see how it's coded if we wanted to get an idea of how money works. 2:20
    So we can see that the cents method returns a fractional or 2:25
    an integer with infinite precision false or 2:30
    big decimal with infinite precision true. 2:36
    Now, we're only going to need to look at this documentation or 2:40
    these methods if we need to. 2:44
    So if we're writing a program and we come across something that we don't understand, 2:47
    it's very useful to be able to look at the source code of the gem that we're using. 2:51
    Then we can also see this requires different files inside of the gem. 2:57
    So if I wanted to look at how the formatting worked, 3:09
    we could look at the formatting.rb file. 3:12
    And we can see how this class is set up. 3:14
    For the most part, we don't need to do this when we're working with gems, but 3:18
    it is useful to know where gems are installed, located, and 3:23
    how they're written. 3:27

    You need to sign up for Treehouse in order to download course files.

    Sign up

      You need to sign up for Treehouse in order to set up Workspace

      Sign up