Several months ago I got curious about how it all worked and wrote up a post of my investigations which you may find useful http://www.alexrothenberg.com/2009/02/i … works.html and of course Ryan Bates did a great Railscast of the same several months after he posted this article which you can watch at http://railscasts.com/episodes/6-shortc … ol-to-proc

Thanks for the clarification, Alex. Much appreciated.

Thanks for your replies - I'll look into it... And not use it after reading Johnson's reply ;-)

I agree the symbol-to-proc syntax looks somewhat confusing but once you get used to it I find it a useful shorthand and would not avoid using it.  In fact while it started as a Rails extension to the Ruby class Symbol it has moved into the Ruby core with 1.8.7 and 1.9 so I expect we'll all be seeing more of it.

Several months ago I got curious about how it all worked and wrote up a post of my investigations which you may find useful http://www.alexrothenberg.com/2009/02/i … works.html and of course Ryan Bates did a great Railscast of the same several months after he posted this article which you can watch at http://railscasts.com/episodes/6-shortc … ol-to-proc

http://blog.hasmanythrough.com/2006/3/7 … -shorthand

google for "rails symbol to proc" for more blog posts etc. about this

Thanks for your replies - I'll look into it... And not use it after reading Johnson's reply ;-)

sections.delete_if(&:blank?)

google for "rails symbol to proc" for more blog posts etc. about this

Regarding the following:

sections.delete_if(&:blank?)

After I had posted I found some examples online of using application helpers and ended up writing pretty much what you wrote for showing "Not supplied" when something was blank. I've not really used helpers a great deal yet but am starting to. I guess when things get repetative in the view and don't seem to fit in the model then helpers are a good solution.

Both my view and model are now looking a lot better. Thanks again for the great advice. BTW I think you should link to the other refactoring tutorials at the top of this one.

The full_address method can be greatly simplified by using a technique similar to what I did in the article - which is placing the address sections in an array and joining that.

def full_address(join_str = ', ')
  sections = [address_line_1, address_line_2, address_line_3] # etc...
  sections.delete_if(&:blank?) # removes any blank entries from the array
  sections.join(join_str)
end

You can go one step further to clean this up a bit more:

def full_address(join_str = ', ')
  address_sections.delete_if(&:blank?).join(join_str)
end
def address_sections
  [address_line_1, address_line_2, address_line_3]
end

Certainly keeping this in the view isn't optimal either. What I would do is create a helper method that handles this for you. You can then input any value you want and it will return "Not Supplied" automatically when blank. For example:

# in view
<%= not_supplied_if_blank @person.job_title %>
# in application_helper
def not_supplied_if_blank(value)
  value.blank? ? "Not Supplied" : value
end

I've done something similar in my person model to create a full_address method from all the individual address fields. I'm sure this could be DRYied up somewhat.

    def full_address
        result = ''
        unless address_line_1.blank?
            result += address_line_1
        end
        unless address_line_2.blank?
            if result == ''
                result += address_line_2
            else
                result += ', ' + address_line_2
            end
        end
        unless address_line_3.blank?
            if result == ''
                result += address_line_3
            else
                result += ', ' + address_line_3
            end
        end
        unless address_line_4.blank?
            if result == ''
                result += address_line_4
            else
                result += ', ' + address_line_4
            end
        end
        unless town.blank?
            if result == ''
                result += town
            else
                result += ', ' + town
            end
        end
        unless county.blank?
            if result == ''
                result += county
            else
                result += ', ' + county
            end
        end
        unless postcode.blank?
            if result == ''
                result += postcode
            else
                result += ', ' + postcode
            end
        end
        result
    end

Also when I am displaying the person's profile details in the view, where a field is not completed I might want to display "Not supplied" or "N/A". Is this best handled in the view or could it be moved to the model too? At the minute I've got a lot of stuff like this in my view:

<%= if @person.job_title.blank? 
            "Not supplied" 
        else 
            @person.job_title 
        end %>

I should really get a rails book...

Added this one as well to my growing (140+) collection below

The first refactoring I will be discussing involves taking a bit of logic out of the view and placing it in the model. This can clean up the views quite nicely.

Let's start out with a very simple example. We have a Person model with first_name, last_name, and middle_initial attributes. In our view we have this code:

Full Name:
<%= @person.first_name %>
<% unless @person.middle_initial.blank? %>
  <%= @person.middle_initial %>.
<% end %>
<%= @person.last_name %>

class Person < ActiveRecord::Base
  def full_name
    result = first_name + ' '
    unless middle_initial.blank?
      result += middle_initial + '. '
    end
    result += last_name
    result
  end
end

Full Name: <%= person.full_name %>

# in person_test.rb
def setup
  @person = Person.new(:first_name => 'John', :last_name => 'Smith')
end
def test_full_name
  assert_equal 'John Smith', @person.full_name
end
def test_full_name_with_middle_initial
  @person.middle_initial = 'A'
  assert_equal 'John A. Smith', @person.full_name
end

def full_name
  [first_name, middle_initial, last_name].join(' ')
end

def middle_initial_with_period
  middle_initial + '.' unless middle_initial.blank?
end
def full_name
  [first_name, middle_initial_with_period, last_name].join(' ')
end

def full_name
  [first_name, middle_initial_with_period, last_name].compact.join(' ')
end

Wait one minute, I hear someone say, the compact method just removes nil values, what if the middle initial is an empty string? Well let's add a test and find out:

def test_full_name_with_empty_middle_initial
  @person.middle_initial = ''
  assert_equal 'John Smith', @person.full_name
end

In this tutorial you learned how to refactor code from the view into the model, but this can just as easily be applied to code in the controller or any other part of the application. Your job is to look through your current rails projects for code that can be moved into a model. Usually if it can be moved into a model, it should, but just be careful to keep view/controller specific code out of the model. For example, don't move HTML code into the model.

If you found this useful, keep an eye out for the next Refactoring on Rails article. In the meantime, check out Martin Fowler's excellent book: Refactoring.

Check out the next article in this series: Multiple Scopes in Controller