refactoring - Dry This Ruby Code -

how can dry out code?

module traversetree   def inorder_traverse root     return nil unless root     result = []     result.concat inorder_traverse root.left if root.left     result.push root.val     result.concat inorder_traverse root.right if root.right     result   end    def preorder_traverse root     return nil unless root     result = []     result.push root.val     result.concat preorder_traverse root.left if root.left     result.concat preorder_traverse root.right if root.right     result   end    def postorder_traverse root     return nil unless root     result = []     result.concat postorder_traverse root.left if root.left     result.concat postorder_traverse root.right if root.right     result.push root.val     result   end end 

is there way programmatically order code based on function names?

thanks!!

def traverse_recurse(root, options)   return unless root   options[:preorder].call(root.val) if options[:preorder]   traverse_recurse(root.left, options)   options[:inorder].call(root.val) if options[:inorder]   traverse_recurse(root.right, options)   options[:postorder].call(root.val) if options[:postorder] end  def traverse_collect(root, type)   result = []   traverse_recurse(root, type => lambda { |val| result.push(val) })   result end  def preorder_traverse(root)   traverse_collect(root, :preorder) end  def inorder_traverse(root)   traverse_collect(root, :inorder) end  def postorder_traverse(root)   traverse_collect(root, :postorder) end