public bool isDistinguishedSymbol(Symbol s) { return (s is Nonterminal && s.Sym == DistinguishedSymbol.Sym); }
public bool isVanishingSymbol(Symbol s) { return _vanishingSymbols.Exists(vs => vs.Sym == s.Sym); }
public bool hasSymbolInRight(Symbol s) { return Right.Exists(rr => rr.Sym == s.Sym); }