[PhillyOnRails] Context-Driven Validations

[Aaron Blohowiak]

A few times at PubNite, we have talked about validations that change  
based on context.. i recently ran accross this cool solution:

http://www.lukeredpath.co.uk/2006/9/28/introduction-to-activespec

A few of us have run in to this: "On a recent project, with a  
particularly complex domain model, there was the need to validate  
objects in different ways, depending on its state and relationship  
with other objects. We found there was a lot of pushback as we tried  
to bend ActiveRecord validations to apply the complex business rules  
needed. We managed it, but the resulting code wasn’t pretty and  
certainly not the elegant, clear code you would come to expect from a  
Ruby or Rails application. In retrospect, the Specification pattern  
would have been an ideal solution."

Aaron Blohowiak