CODEWITHSUNDEEP
ruby-on-railsruby
kjb
kjb

Reputation: 3175

Auto-create the containing module of a class

In Rails you can create a model under app/foo/bar.rb, with bar.rb containing:

class Foo::Bar
  def some_method
    puts "I work fine"
  end
end

If you try to do this in a pure ruby app you'd get a NameError: uninitialized constant Foo unless you've already initialized a module Foo.

What is Rails doing that allows it to create classes without first initializing their containing module? Is it possible to import this behavior through something like activesupport, or are we left to implement on our own?

Upvotes: 4

Views: 318

Answers (2)

Don Cruickshank
Don Cruickshank

Reputation: 5948

Rails modifies the Class class to include a const_missing method which gets called when an undefined class is used. It then loads things to try and load the requested class.

The implementation of this in ActiveSupport is in lib/active_support/dependencies.rb.

Upvotes: 3

Nich
Nich

Reputation: 1102

actually model class created is extend to < ActiveRecord::Base

Upvotes: -1

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