CODEWITHSUNDEEP
ruby
Mike
Mike

Reputation: 33

Using packages in Ruby?

I just started learning Ruby coming from Java. In Java you would use packages for a bigger projects. Is there anything equivalent to that in Ruby? Or what is the best way to achieve a package like setting?

The way I'm doing it right now is 'load'ing all the needed class into my new Ruby file. Isn't there a way to tell my current Ruby class to use all other Ruby classes in the same folder?

Cheers, Mike

Upvotes: 3

Views: 1168

Answers (3)

tadman
tadman

Reputation: 211560

There's three kinds of package loading in Ruby:

  • Explicitly loading a library with require
  • Implicitly loading a library using autoload
  • Importing a library with gem

The require method is the most direct and has the effect of loading in and executing that particular file. Since that file may go on to require others, as a matter of convenience, you may end up loading in quite a lot at once.

The autoload method declares a module that will be loaded if you reference a given symbol. This is a common method to avoid loading things that you don't need, but making them automatically available if you do. Most large libraries use this method of loading to avoid dumping every single class into memory at once.

The gem approach is a more formalized way of packaging up a library. Although it is uncommon for applications to be split up into one or more gems, it is possible and provides some advantages. There's no obligation to publish a gem as open-source, you can keep it private and distribute it through your own channels, either a private web site or git repository, for instance, or simply copy and install the .gem file as required.

That being said, if you want to make a library that automatically loads a bunch of things, you might take this approach:

# lib/example.rb
Dir.glob(File.expand_path('example/**/*.rb', File.dirname(__FILE__))).each do |file|
  require file
end

This would load all the .rb files in lib/example when you call require 'example'.

Upvotes: 1

Andy
Andy

Reputation: 1490

You probably want to use require rather than load, since it should take care of circular references.

If you want to grab all the files in a given folder, that's easy enough:

Dir.foreach("lib"){|x| require x}

Your other option is to have a file that manually requires everything, and have your other files require that.

You should also look at wrapping the code in your libraries with a module block, to give them their own namespaces.

That said: rightly or wrongly, I tend to feel that this is the one area -- perhaps the only one -- where Ruby is less powerful than Python, say, or Java.

Upvotes: 1

lucapette
lucapette

Reputation: 20724

I understand your feeling. It's an ordinary problem you have to face when coming from another language like Java. I'd say try to study Ruby modules but you deserve a longer reply. So my advice is reading a good Ruby book like Eloquent Ruby.

Upvotes: 0

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