class Treetop::Runtime::SyntaxNode

def empty?
  interval.first == interval.last && interval.exclude_end?
end

def extension_modules
  local_extensions =
    class <<self
      included_modules-Object.included_modules
    end
  if local_extensions.size > 0
    local_extensions
  else
    []    # There weren't any; must be a literal node
  end
end

def initialize(input, interval, elements = nil)
  @input = input
  @interval = interval
  if @elements = elements
    elements.each do |element|
      element.parent = self
    end
  end
end

def inspect(indent="")
  em = extension_modules
  interesting_methods = methods-[em.last ? em.last.methods : nil]-self.class.instance_methods
  im = interesting_methods.size > 0 ? " (#{interesting_methods.join(",")})" : ""
  tv = text_value
  tv = "...#{tv[-20..-1]}" if tv.size > 20
  indent +
  self.class.to_s.sub(/.*:/,'') +
    em.map{|m| "+"+m.to_s.sub(/.*:/,'')}*"" +
    " offset=#{interval.first}" +
    ", #{tv.inspect}" +
    im +
    (elements && elements.size > 0 ?
      ":" +
        (@elements||[]).map{|e|
    begin
      "\n"+e.inspect(indent+"  ")
    rescue  # Defend against inspect not taking a parameter
      "\n"+indent+" "+e.inspect
    end
        }.join("") :
      ""
    )
end

def nonterminal?
  !terminal?
end

def terminal?
  @elements.nil?
end

def text_value
  input[interval]
end