def hello
  puts "hello world"
  puts "hello hell"
end

class Method
  SHOW_TRACE = false
  def trace_func event, file, line, id, binding, classname
    puts "%8s %s:%-2d %s %8s" % [event, file, line, id, classname] if SHOW_TRACE
    return unless event == 'call'
    set_trace_func nil

    @file, @line = file, line
    raise :found
  end

  def source_location
    if @file.nil?
      args =[*(1..(arity<-1 ? -arity-1 : arity ))]

      set_trace_func method(:trace_func).to_proc
#      begin; call *args; rescue Exception=>e; puts e.to_s; puts e.backtrace; end
      call *args rescue nil
      set_trace_func nil
      @file = File.expand_path(@file) if @file && File.exist?(File.expand_path(@file))
    end
    return [@file, @line] if File.exist?(@file.to_s)
  end
end

puts method(:hello).source_location.inspect