public Cfg<T> build() {
			return Cfg.of(rules);
		}
Creates a new CFG object.

@see #of(List)

@throws IllegalArgumentException if the rule list is empty or a rule
        is defined more than once, the start symbol points to a
        missing rule or the rules uses symbols not defined in the
        list of {@link #nonTerminals()} or {@link #terminals()}
@return a newly created CFG object
jenetics.ext/src/main/java/io/jenetics/ext/grammar/Cfg.java