uninitialize.rb

class Value
  class << self
    alias [] new
  end

  def ==(other)
    return false unless other.is_a? self.class
    self.uninitialize == other.uninitialize
  end
  alias_method :eql?, :==

  def inspect
    values = uninitialize.reverse.drop_while(&:nil?).reverse
    self.class.to_s + values.inspect
  end
  alias_method :to_s, :inspect

  def hash
    [self.class, uninitialize].hash
  end
end

class Node < Value
  attr_reader :source, :range, :children, :name

  def initialize(source, range, children=nil, name=nil)
    @source, @range, @children, @name = source, range, children.to_a, name
  end

  def uninitialize
    [@source, @range, @children, @name]
  end
end

p Node['source', 0..2, [], 'name']
# => Node["source", 0..2, [], "name"]

p Node['source', 0..2]
# => Node["source", 0..2, []]