class Racc::Parser

The final symbol (End of file) must be false.

for 'IDENT'. ";" (String) for ';'.
+token-symbol+ is represented by Ruby's symbol by default, e.g. :IDENT
The format of return value is [TOKEN_SYMBOL, VALUE].

If you use #do_parse method, you must implement #next_token.
The method to fetch next token.

def next_token
  raise NotImplementedError, "#{self.class}\#next_token is not defined"
end