// same algorithm as above
/// <exception cref="NotComputedException"></exception>
public FirstResult Sequence(IEnumerable <Symbol> syms)
{
_ = Algo.Nullable ?? throw new NotComputedException(nameof(Algo.Nullable));
var result = new FirstResult();
foreach (var Bi in syms)
{
if (Bi.Type == Symbol.Types.Terminal)
{
result.Add(Bi);
break;
}
else
{
result.UnionWith(this[Bi]);
}
if (!Algo.Nullable[Bi])
{
break;
}
}
return(result);
}
