Tip: Ruby On Rails Returning

Posted by anthony crumley, Wed Dec 05 14:02:00 UTC 2007

The Rails returning method can clarify your code. Its basic purpose is to semantically group code that creates the return value for a method. We could discuss its K Combinator Lambda Calculus roots but we won’t go there. Heck, I don’t even remember what that crap is.

Returning accepts two parameters. The first parameter initializes the return value. The second parameter is a block that creates the return value.

Returning doesn’t usually save lines of code or help with performance but it does make things a little clearer. One thing it does well is separate setup code from code that actually creates the return value. Consider the following helper method that returns the full name of a user.

def full_name(user)
  user = current_user unless user

  name = user.first_name
  name << ' ' + user.middle_name unless user.middle_name.blank?
  name << ' ' + user.last_name
  name
end

Now the same method using returning to clarify what is being returned.

def full_name(user)
  user = current_user unless user

  returning String.new do |name|
    name << user.first_name
    name << ' ' + user.middle_name unless user.middle_name.blank?
    name << ' ' + user.last_name
  end
end

Filed Under: | Tags: anthony rails