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@@ -77,6 +77,27 @@ Creating the add button is equally simple. The add_associated_link helper will d
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 That's all you have to do to create a multi-model form with attribute_fu!
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+== Discarding Blank Child Models
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+
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+If you want to show a bunch of blank child model forms at the bottom of your form, but you only want to save the ones that are filled out, you can use the discard_if option. It accepts either a proc:
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+
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+  class Project < ActiveRecord::Base
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+    has_many :tasks, :attributes => true, :discard_if => proc { |task| task.title.blank? }
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+  end
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+
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+...or a symbol...
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+
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+  class Project < ActiveRecord::Base
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+    has_many :tasks, :attributes => true, :discard_if => :blank?
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+  end
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+  
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+  class Task < ActiveRecord::Base
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+    def blank?
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+      title.blank?
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+    end
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+  end
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+
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+Using a symbol allows you to keep code DRYer if you are using that routine in more than one place. Both of those examples, however, would have the same effect.
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 = Updates
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