Question

I have recently started using Ruby, so quite new to this. My current objective is to use a ruby module called retort, my problem is that I don’t understand the configure method which is looking like this:

def configure
    config = Config.new
    yield config
    @@service = XMLRPC::Client.new2(config.url)
end

Config class is simple and looks like:

class Config
    attr_accessor :url
end

I tried to create a small example to play around in order to understand how exactly that is supposed to work:

class TestClass
  def test_method
     config = String.new
     yield config
     p config
  end
end

d = TestClass.new
d.test_method { 'test string' }

Of course it doesn’t return ‘test string’ but an empty string.

Thank you for any help 🙂

Answer 1

Can you be clearer about what’s confusing you? Does this code make sense to you?

class TestClass
  def test_method
    config = yield
    p config
  end
end

d.test_method { "test string" }

The yield statement invokes the block. The block returns a string, which is assigned to the config variable back in the test_method and is then printed. Does that make it clearer?

In your code, the line yield config is invoking the block while passing in the just-instantiated Config object. For instance:

def foo
  s = "a string"
  yield s
  p "In foo printing " + s
end

foo { |x| p "In block printing " + x }