/// <summary>
/// The rule that indicates the <see cref="Terminal"/> does not appear in the input text.
/// </summary>
/// <param name="lhs">The <see cref="OptionalTerminal{T}"/> represeting the LHS of the rule.</param>
public static void Rule(OptionalTerminal <T> lhs)
{
}
/// <summary>
/// The rule that indicates the <see cref="Terminal"/> appears in the input text.
/// </summary>
/// <param name="lhs">The <see cref="OptionalTerminal{T}"/> represeting the LHS of the rule.</param>
/// <param name="rhs">The <see cref="Terminal"/> representing the RHS of the rule.</param>
public static void Rule(OptionalTerminal <T> lhs, T rhs)
{
lhs.Rhs = rhs;
}