Chapter 6 - Programming Languages - Section 6.4 - Language Implementation - Questions & Exercises - Page 307: 4

The strings that conform to the structure Chacha consist of one or more of the following substrings: forward backward cha cha cha backward forward cha cha cha swing right cha cha cha swing left cha cha cha

The strings that conform to the structure Chacha consist of one or more of the following substrings: forward backward cha cha cha backward forward cha cha cha swing right cha cha cha swing left cha cha cha