Extensions for acts_as_tree

Filed in: Rails, Ruby Add comments

While the acts_as_tree rails plugin ( http://dev.rubyonrails.com/svn/rails/plugins/acts_as_tree ) provides some basic methods for accessing tree like data structure, I found that it lacks some basic ones, for example – has_children? and has_siblings?
Other than that, it would have been nice to know the tree width and depth (especially if you need to draw it, and need to calculate the scaling.

module ActiveRecord
  module Acts
    module Tree
      module InstanceMethods
        def has_children?
          !self.children.size.zero?
        end
 
        def has_siblings?
          !self.siblings.size.zero?
        end
 
        # Return the tree depth
        def depth
          return 0 unless has_children?
          children.inject(0) {|dep,c| dep > c.depth ? dep : c.depth} + 1
        end
 
        # Return the tree width
        def width
          return 1 unless has_children?
          children.inject(0) {|sum,c| sum + c.width}
        end
      end
    end
  end
end

Maybe if I won’t be lazy, I’ll write some tests and send this for inclusion in the plugin…

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