Add decorates_assigned method to controllers

[haines]

I gave the decorates_assigned feature I mentioned a whirl.

I think it's quite nifty, basically it produces a helper method like this

decorates_assigned :article
# generates
def article
  return @decorated_article if defined?(@decorated_article)
  @decorated_article = factory.decorate(@article)
end
helper_method :article

where the factory handles options and automagical guessing of collections, so that you can do things like

decorates_assigned :article, with: FancyArticleDecorator
decorates_assigned :articles, with: PaginatingCollectionDecorator

It's very similar behaviour to decorates_association, and indeed, Factory is extracted from that class.

Then you just replace @article with article in your view, and away you go. No more getting bitten by immutable decorators in your controller actions.

See what you think!

[steveklabnik]

👍