Taming The View for Rubyconf India

Taming of the ViewRubyConf India 2010Sarah Taraporewalla

ThoughtWorks

Sunday, 21 March 2010

I will attempt to convince you that:



- the current template engines are too permissive




- there are loads of code bases that break fundamental principles





- you should turn to other template engines


What is wrong with these examples?


Example 1


Example 2


Example 3


Example 4


AGH! This is really really easy in Rails3

now!


Controller


Why do we get thin controllers?


Push vs Pull

http://www.flickr.com/photos/91772025@N00/444044158/ CC BY-ND 2.0


http://www.flickr.com/photos/91772025@N00/

http://www.flickr.com/photos/91772025@N00/

Pull

View Controllers Model


Pull - over time

ViewControllers Model


Push

View Controllers Model


Push - over time

View

Controllers

Model


Push - and then

View Controllers Services


What do we want?


Testable Code


Testable Code

Don’t put logic in your views


Single Responsibility


Single Responsibility

Don’t let changes in column names effect your views


Separation of Concerns


Separation of Concerns

Enforce strict separation of model and view


How do we improve on the examples?


Example 1 - Before


Example 1 - Improved


Example 2 - Before


Example 2 - Improved


Example 3 - Before


Example 4 - Before


Example 3,4 - Improved


If you make it easy to do the wrong thing, the

wrong thing will be done


If you make it easy to do the right thing, the

right thing will be done


Haml


Haml

Good


Haml

Good

But ...


Haml

Good

But ...

still allows ruby


String Template


StringTemplate

- Strict separation of model & view

- Fits well with functional programming

- Written in Java, .Net, Python

is NOT Turing complete


1. Create a StringTemplate Object with the template


1. Create a StringTemplate Object with the template

string or file


2. Set attributes and their values


3. Call toString() to mash attributes onto the template


Testable?


Testable? Yes!


Single Responsibility?


Single Responsibility? Yes!


Separation of Concerns?


Separation of Concerns? Yes!

It is the essence of its philosophy


Other cool things...


Templates (Partials)


Iterators


Renderers


Localisation


But, we do Ruby


Slippers


Slippers & Ramaze


Slippers - Example


Slippers - Exampleindex.st

person/index.st

person/age.stSunday, 21 March 2010

Slippers - Exampleperson/age_renderer.rb

controller/role_renderer.rb


Slippers - Example


Slippers - Testable?

• Holes are correctly plugged

• Correct instance variables set

• Renderers




• Renderers



Slippers


Slippers

• Can be found at:

‣ http://slippersRb.com

‣ http://github.com/starapor/slippers

‣ http://gemcutter.org/gems/slippers

• Ramaze view template

‣ http://ramaze.net


http://slippersRb.com

http://slippersRb.com

http://github.com/starapor/slippers

http://github.com/starapor/slippers

http://gemcutter.org/gems/slippers

http://gemcutter.org/gems/slippers

Have I convinced you that:





- we should turn to other template engines


questions?


Taming The View for Rubyconf India

Technology

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