The document outlines best practices for simplifying and refactoring code, emphasizing the importance of intention-revealing methods and the use of special case objects to streamline handling of null values. It discusses techniques for improving code readability and maintenance, such as extracting methods and replacing lengthy methods with method objects. Resources and examples are provided for each technique to aid developers in enhancing their coding practices.

1. def simplifying_code
{
author: "Jonathan Cabas"
follow: "@jcabasc"
}
end

2. Refactoring
4. GDD: Guilt Driven Development.
3. Learning of new techniques.
1. Improve our code.
2. Keep it simple.
Why?

3. Refactoring
Without test:
With test:
Conditions

4. Refactoring
1. Intention Revealing Method.
2. Special Case.
3. Replace method with method
object.

5. Intention Revealing Method
2.You have comments that explain what / how to do a method.
(or Extract Method)
1. You have a snippet of code that can be grouped together.
3. Turn the fragment/comment into a method whose name
explains the purpose of the method.
Code describes.
4. Change the original method to use the new one.

6. Intention Revealing Method
2. A method does more than one thing.
3. You have comments about a method that does not explain
why you would call it.
Why?
4. The code is mixed with different levels of abstractions.
High-level and low-level operations.
1. A method is too long.

7. Intention Revealing Method
• http://www.codinghorror.com/blog/2008/07/coding-without-comments.htm
Resources
• http://ntcoding.blogspot.com.ar/2011/05/clean-code-tricks-intention-
revealing.html
• http://c2.com/cgi/wiki?ExtractMethod
• http://java.dzone.com/articles/clean-code-dont-mix-different
• http://signalvnoise.com/posts/3531-intention-revealing-methods

8. Special Case Object
Get rid of ifs or trys
Instead of returning null or some odd value, return a special
case that has the same interface as what the caller expects.
Very often, we would like to execute some action only if an
object is present:
if current_user
#cool stuff
end
undefined method 'send_for_beer' for nil:NilClass (NoMethodError)

9. def current_user
if session[:user_id]
User.find(session[:user_id])
end
end
def welcome
"Hello, " +
current_user ? current_username : "guest" +
", how are you today?"
end
if current_user
render_logout_button
else
render_login_button
end
if current_user && current_user.is_admin?
render_admin_site
end
if current_user
@posts = current_user.visible_posts
else
@posts = Post.published
end
if current_user
current_user.last_seen = Time.now
end
cart = if current_user
current_user.cart
else
SessionCart.new(session)
end
cart.add_item(some_item, 1)
class GuestUser
def initialize(session)
@session = session
end
end

10. class GuestUser
def initialize(session)
@session = session
end
end
def current_user
if session[:user_id]
User.find(session[:user_id])
else
GuestUser.new(session)
end
end
class GuestUser
def initialize(session)
@session = session
end
def name
"Guest"
end
end
def welcome
"Hello, " +
current_user ? current_username : "guest" +
", how are you today?"
end
def welcome
“Hello,#{current_user.name}, how are you?”
end
class User
# ...
def authenticated?
true
end
end
if current_user
render_logout_button
else
render_login_button
end
class GuestUser
def initialize(session)
@session = session
end
def name
"Guest"
end
def authenticated?
false
end
end
if current_user.authenticated?
render_logout_button
else
render_login_button
end
if current_user && current_user.is_admin?
render_admin_site
end
if current_user.is_admin?
render_admin_site
end
class GuestUser
def initialize(session)
@session = session
end
def name
"Guest"
end
def authenticated?
false
end
def is_admin?
false
end
end
if current_user
@posts = current_user.visible_posts
else
@posts = Post.published
end
class GuestUser
def initialize(session)
@session = session
end
def name
"Guest"
end
def authenticated?
false
end
def is_admin?
false
end
def visible_posts
Post.published
end
end@posts = current_user.visible_posts
if current_user
current_user.last_seen = Time.now
end
class GuestUser
def initialize(session)
@session = session
end
def name
"Guest"
end
def authenticated?
false
end
def is_admin?
false
end
def visible_posts
Post.published
end
def last_seen_online=(time)
#NOOP
end
end
current_user.last_seen = Time.now
cart = if current_user
current_user.cart
else
SessionCart.new(session)
end
cart.add_item(some_item, 1)
class GuestUser
def initialize(session)
@session = session
end
def name
"Guest"
end
def authenticated?
false
end
def is_admin?
false
end
def visible_posts
Post.published
end
def last_seen_online=(time)
#NOOP
end
def cart
SessionCart.new(session)
end
end
current_user.cart.add_item(some_item, 1)

11. 2. The need of a “do nothing”/ default behaviour.
Why?
1. You want to abstract the handling of null away from the
client. ( Treat the presence of a null reference in a transparent
way).
Special Case Object

12. Special Case Object
• http://martinfowler.com/eaaCatalog/specialCase.html
Resources
• http://devblog.avdi.org/2011/05/30/null-objects-and-falsiness/
• http://www.cs.oberlin.edu/~jwalker/nullObjPattern/
• http://nickknowlson.com/blog/2013/04/16/why-maybe-is-better-than-null/
• http://sourcemaking.com/design_patterns/null_object
• RubyTapas #112

13. Replace method with
method object
class Order
def price(primary_base_price, secondary_base_price, tertiary_base_price)
# 1 chillion lines of code, lots of local variables
end
end

14. Replace method with
method object
1. Create a class with same initialization arguments as BIG
method.
2. Copy & Paste the method's body in the new class, with no
arguments.
3. Replace original method with a call to the new class.
4. Apply “Extract method” to the class.

15. Replace method with
method object
1. You have a long method with a lot of temporary variables.
2. Your long method uses local variables in such a way that
you can’t apply “extract method”.
3. You don’t want to pass those local variables around as you
extract methods.
Why?

16. • http://confreaks.com/videos/1071-cascadiaruby2012-therapeutic-
refactoring
• http://www.refactoring.com/catalog/replaceMethodWithMethodObject.htm
• http://sourcemaking.com/refactoring/replace-method-with-method-object
Replace method with
method object
Resources

17. Thank you note