# File lib/abstract.rb, line 65
65:   def not_implemented     #:doc:
66:     backtrace = caller()
67:     method_name = (backtrace.shift =~ /`(\w+)'$/) && $1
68:     mesg = "class #{self.class.name} must implement abstract method '#{method_name}()'."
69:     #mesg = "#{self.class.name}##{method_name}() is not implemented."
70:     err = NotImplementedError.new mesg
71:     err.set_backtrace backtrace
72:     raise err
73:   end