class Sequitur::Production

In a context-free grammar, a production is a rule in which its left-hand side (LHS) consists solely of a non-terminal symbol and the right-hand side (RHS) consists of a sequence of symbols. The symbols in RHS can be either terminal or non-terminal symbols. The rule stipulates that the LHS is equivalent to the RHS, in other words every occurrence of the LHS can be substituted to corresponding RHS. Implementation note: the object id of the production is taken as its LHS.