Make it possible to add optional methods to continuable_base depending on the annotation

include/continuable/continuable-base.hpp

@@ -90,7 +90,9 @@ using is_continuable = detail::base::is_continuable<T>;
 ///
 /// \since 1.0.0
 template <typename Data, typename Annotation>
-class continuable_base {
+class continuable_base
+    : public detail::annotation_trait<Annotation>::template //
+      annotation_base<continuable_base<Data, Annotation>> {
 
   /// \cond false
   using ownership = detail::util::ownership;
@@ -99,11 +101,6 @@ class continuable_base {
   friend class continuable_base;
   friend struct detail::base::attorney;
 
-  // The materializer which is used when this continuable_base is an
-  // expression template such that is_connection_strategy<Annotation>::value
-  // holds for the Annotation.
-  using materializer = detail::connection::materializer<continuable_base>;
-
   // The continuation type or intermediate result
   Data data_;
   // The transferable state which represents the validity of the object
@@ -565,6 +562,7 @@ public:
     detail::base::finalize_continuation(std::move(*this));
   }
 
+#ifdef CONTINUABLE_HAS_DOXYGEN
   /// Materializes the continuation expression template and finishes
   /// the current applied strategy.
   ///
@@ -588,9 +586,8 @@ public:
   ///       on conversion.
   ///
   /// \since 4.0.0
-  auto finish() && {
-    return materializer::apply(std::move(*this));
-  }
+  unspecified finish() &&;
+#endif // CONTINUABLE_HAS_DOXYGEN
 
 #ifdef CONTINUABLE_HAS_DOXYGEN
   /// Returns true if the continuable_base will resolve its promise

include/continuable/detail/connection/connection-all.hpp

@@ -40,8 +40,8 @@
 #include <continuable/continuable-primitives.hpp>
 #include <continuable/detail/connection/connection-aggregated.hpp>
 #include <continuable/detail/connection/connection.hpp>
-#include <continuable/detail/core/base.hpp>
 #include <continuable/detail/core/annotation.hpp>
+#include <continuable/detail/core/base.hpp>
 #include <continuable/detail/core/types.hpp>
 #include <continuable/detail/utility/traits.hpp>
 
@@ -164,7 +164,6 @@ struct connection_finalizer<connection_strategy_all_tag> {
 
     return base::attorney::create_from(
         [result = std::move(result)](auto&& callback) mutable {
-
           using submitter_t =
               all::result_submitter<std::decay_t<decltype(callback)>,
                                     std::decay_t<decltype(result)>>;
@@ -186,6 +185,12 @@ struct connection_finalizer<connection_strategy_all_tag> {
   }
 };
 } // namespace connection
+
+/// Specialization for a connection annotation
+template <>
+struct annotation_trait<connection::connection_strategy_all_tag>
+    : connection::connection_annotation_trait {};
+
 } // namespace detail
 } // namespace cti
 

include/continuable/detail/connection/connection-any.hpp

@@ -40,8 +40,8 @@
 #include <continuable/continuable-primitives.hpp>
 #include <continuable/continuable-promise-base.hpp>
 #include <continuable/continuable-traverse.hpp>
-#include <continuable/detail/core/base.hpp>
 #include <continuable/detail/core/annotation.hpp>
+#include <continuable/detail/core/base.hpp>
 #include <continuable/detail/core/types.hpp>
 #include <continuable/detail/traversal/container-category.hpp>
 #include <continuable/detail/utility/traits.hpp>
@@ -177,7 +177,6 @@ struct connection_finalizer<connection_strategy_any_tag> {
     return base::attorney::create_from(
         [connection =
              std::forward<Connection>(connection)](auto&& callback) mutable {
-
           using submitter_t =
               any::any_result_submitter<std::decay_t<decltype(callback)>>;
 
@@ -193,6 +192,12 @@ struct connection_finalizer<connection_strategy_any_tag> {
   }
 };
 } // namespace connection
+
+  /// Specialization for a connection annotation
+template <>
+struct annotation_trait<connection::connection_strategy_any_tag>
+  : connection::connection_annotation_trait {};
+
 } // namespace detail
 } // namespace cti
 

include/continuable/detail/connection/connection-seq.hpp

@@ -160,6 +160,12 @@ struct connection_finalizer<connection_strategy_seq_tag> {
   }
 };
 } // namespace connection
+
+/// Specialization for a connection annotation
+template <>
+struct annotation_trait<connection::connection_strategy_seq_tag>
+    : connection::connection_annotation_trait {};
+
 } // namespace detail
 } // namespace cti
 

include/continuable/detail/connection/connection.hpp

@@ -124,9 +124,16 @@ auto connect(Strategy strategy, continuable_base<LData, LAnnotation>&& left,
 template <typename Strategy>
 struct connection_finalizer;
 
-/// Finalizes the connection logic of a given connection
-template <typename Data, typename Strategy>
-auto finalize_connection(continuable_base<Data, Strategy>&& continuation) {
+struct connection_annotation_trait {
+  template <typename Continuable>
+  struct annotation_base;
+  template <typename Data, typename Strategy>
+  struct annotation_base<continuable_base<Data, Strategy>> {
+    /// Finalizes the connection logic of a given connection
+    auto finish() && {
+      using continuable_t = continuable_base<Data, Strategy>;
+      auto&& continuation = std::move(*static_cast<continuable_t*>(this));
+
       using finalizer = connection_finalizer<Strategy>;
 
       util::ownership ownership = base::attorney::ownership_of(continuation);
@@ -134,23 +141,10 @@ auto finalize_connection(continuable_base<Data, Strategy>&& continuation) {
 
       // Return a new continuable which
       return finalizer::finalize(std::move(connection), std::move(ownership));
-}
-
-/// A base class from which the continuable may inherit in order to
-/// provide a materializer method which will finalize an oustanding strategy.
-template <typename Continuable, typename = void>
-struct materializer {
-  static constexpr auto&& apply(Continuable&& continuable) {
-    return std::move(continuable);
     }
-};
-template <typename Data, typename Strategy>
-struct materializer<continuable_base<Data, Strategy>,
-                    std::enable_if_t<is_connection_strategy<Strategy>::value>> {
+  };
 
-  static constexpr auto apply(continuable_base<Data, Strategy>&& continuable) {
-    return finalize_connection(std::move(continuable));
-  }
+  using is_concrete = std::false_type;
 };
 
 class prepare_continuables {

include/continuable/detail/core/annotation.hpp

@@ -43,9 +43,16 @@ struct annotation_trait;
 /// Specialization for a present signature hint
 template <typename... Args>
 struct annotation_trait<traits::identity<Args...>> {
-  using is_concrete_hint = std::true_type;
-  using hint_t = traits::identity<Args...>;
-  using is_materialized = std::true_type;
+  template <typename Continuable>
+  struct annotation_base {
+    Continuable&& finish() {
+      return std::move(*static_cast<Continuable*>(this));
+    }
+
+    static constexpr bool is_concrete = true;
+  };
+
+  using is_concrete = std::true_type;
 };
 
 namespace hints {