Class ControlFlow

include/process/loop.hpp:163–219

// the functions `Continue()` and `Break(...)`).
template <typename T>
class ControlFlow
{
public:
  using ValueType = T;

  enum class Statement
  {
    CONTINUE,
    BREAK
  };

  class Continue
  {
  public:
    Continue() = default;

    template <typename U>
    operator ControlFlow<U>() const
    {
      return ControlFlow<U>(ControlFlow<U>::Statement::CONTINUE, None());
    }
  };

  class Break
  {
  public:
    Break(T t) : t(std::move(t)) {}

    template <typename U>
    operator ControlFlow<U>() const &
    {
      return ControlFlow<U>(ControlFlow<U>::Statement::BREAK, t);
    }

    template <typename U>
    operator ControlFlow<U>() &&
    {
      return ControlFlow<U>(ControlFlow<U>::Statement::BREAK, std::move(t));
    }

  private:
    T t;
  };

  ControlFlow(Statement s, Option<T> t) : s(s), t(std::move(t)) {}

  Statement statement() const { return s; }

  T& value() & { return t.get(); }
  const T& value() const & { return t.get(); }
  T&& value() && { return t.get(); }
  const T&& value() const && { return t.get(); }

private:
  Statement s;
  Option<T> t;
};