public bool IsAssignmentOperator()
        {
            return this.Is(TokenType.Equal) ||
                this.Is(TokenType.AssignAdd) ||
                this.Is(TokenType.AssignSubtract) ||
                this.Is(TokenType.AssignMultiply) ||
                this.Is(TokenType.AssignDivide) ||
                this.Is(TokenType.AssignConcatenate);
        }

        public bool IsNonScriptToken()
        {
            return this.Is(TokenType.Directive) ||
                this.Is(TokenType.Comment) ||
                this.Is(TokenType.NewLine) ||
                this.Is(TokenType.Nil);
        }

        public bool IsOperator()
        {
            return this.IsBinaryOperator() || this.IsUnaryOperator();
        }