Ruby.scala is a simple parser written in the language Scala by using parser combinators for ISO Ruby, ISO/IEC 30170:2012. It is written by Dr. Ikuo Nakata, the chairman of the working group for the standardization of the language Ruby, with the help by Dr. Kota Mizushima, a deputation of Japan Scala Users Group and working at Ubiregi Inc. Ruby.scala directly follows the syntax of ISO Ruby, except