Adapt the small functor capacity to hold a ready continuable at zero cost

include/continuable/continuable-base.hpp

@@ -849,7 +849,7 @@ constexpr auto make_continuable(Continuation&& continuation) {
 
   return detail::base::attorney::create_from(
       std::forward<Continuation>(continuation),
-      detail::hints::extract(detail::traits::identity<Args...>{}),
+      detail::hints::from_explicit(detail::traits::identity<Args...>{}),
       detail::util::ownership{});
 }
 
@@ -864,41 +864,22 @@ constexpr auto make_continuable(Continuation&& continuation) {
 ///
 /// \since     3.0.0
 template <typename... Args>
-constexpr auto make_ready_continuable() {
-  return make_continuable<void>([](auto&& promise) {
-    std::forward<decltype(promise)>(promise).set_value();
-  });
+auto make_ready_continuable() {
+  static_assert(
+      sizeof...(Args) == 0,
+      "make_ready_continuable with void continuables requires zero args!");
+  return make_continuable<void>(detail::base::ready_continuable<>());
 }
 
 /// Returns a continuable_base with one result value which instantly resolves
 /// the promise with the given value.
 ///
 /// \copydetails make_ready_continuable()
-template <typename Result>
-constexpr auto make_ready_continuable(Result&& result) {
-  return make_continuable<std::decay_t<Result>>( // ...
-      [result = std::forward<Result>(result)](auto&& promise) mutable {
-        std::forward<decltype(promise)>(promise).set_value(std::move(result));
-      });
-}
-
-/// Returns a continuable_base with multiple result values which instantly
-/// resolves the promise with the given values.
-///
-/// \copydetails make_ready_continuable()
-template <typename FirstResult, typename SecondResult, typename... Rest>
-constexpr auto make_ready_continuable(FirstResult&& first_result,
-                                      SecondResult&& second_result,
-                                      Rest&&... rest) {
-  return make_continuable<std::decay_t<FirstResult>, std::decay_t<SecondResult>,
-                          std::decay_t<Rest>...>( // ...
-      [result = std::make_tuple(std::forward<FirstResult>(first_result),
-                                std::forward<SecondResult>(second_result),
-                                std::forward<Rest>(rest)...)](
-          auto&& promise) mutable {
-        detail::traits::unpack(std::forward<decltype(promise)>(promise),
-                               std::move(result));
-      });
+template <typename... Args>
+auto make_ready_continuable(Args&&... args) {
+  return make_continuable<std::decay_t<Args>...>(
+      detail::base::ready_continuable<std::decay_t<Args>...>(
+          std::forward<Args>(args)));
 }
 
 /// Returns a continuable_base with the parameterized result which instantly

include/continuable/continuable-trait.hpp

@@ -32,8 +32,8 @@
 #define CONTINUABLE_TRAIT_HPP_INCLUDED
 
 #include <cstddef>
-#include <continuable/continuable-primitives.hpp>
 #include <continuable/continuable-base.hpp>
+#include <continuable/continuable-primitives.hpp>
 #include <continuable/continuable-promise-base.hpp>
 #include <continuable/detail/core/annotation.hpp>
 #include <continuable/detail/core/types.hpp>
@@ -61,18 +61,17 @@ template <template <std::size_t, typename...> class CallbackWrapper,
 class continuable_trait {
 
   using callback = CallbackWrapper<0U, void(Args...)&&,
-                                   void(exception_arg_t,
-                                        exception_t) &&>;
+                                   void(exception_arg_t, exception_t) &&>;
 
 public:
   /// The promise type which is used to resolve continuations
-  using promise =
-      promise_base<callback, detail::traits::identity<Args...>>;
+  using promise = promise_base<callback, detail::traits::identity<Args...>>;
 
   /// The continuable type for the given parameters.
-  using continuable =
-      continuable_base<ContinuationWrapper<sizeof(callback), void(promise)>,
-                       detail::traits::identity<Args...>>;
+  using continuable = continuable_base<
+      ContinuationWrapper<sizeof(detail::base::ready_continuable<Args...>),
+                          void(promise)>,
+      detail::traits::identity<Args...>>;
 };
 /// \}
 } // namespace cti

include/continuable/detail/core/annotation.hpp

@@ -54,13 +54,13 @@ namespace hints {
 ///
 /// This is the overload taking an arbitrary amount of args
 template <typename... HintArgs>
-constexpr auto extract(traits::identity<HintArgs...> hint) {
+constexpr auto from_explicit(traits::identity<HintArgs...> hint) {
   return hint;
 }
-/// \copybrief extract
+/// \copybrief from_explicit
 ///
 /// This is the overload taking a void arg.
-constexpr auto extract(traits::identity<void> /*hint*/) {
+constexpr auto from_explicit(traits::identity<void> /*hint*/) {
   return traits::identity<>{};
 }
 } // namespace hints

include/continuable/detail/core/base.hpp

@@ -69,23 +69,40 @@ struct is_continuable : std::false_type {};
 template <typename Data, typename Annotation>
 struct is_continuable<continuable_base<Data, Annotation>> : std::true_type {};
 
-/*template <typename... Args>
+template <typename... Args>
 struct ready_continuable {
   std::tuple<Args...> values_;
 
+  explicit ready_continuable(Args... values) : values_(std::move(values)) {
+  }
+
   template <typename Callback>
   void operator()(Callback&& callback) && {
     traits::unpack(std::forward<Callback>(callback), std::move(values_));
   }
 
-  bool operator()(is_ready_arg_t) const noexcept {
+  /*bool operator()(is_ready_arg_t) const noexcept {
     return true;
   }
 
   std::tuple<Args...> operator()(get_arg_t) && {
     return std::move(values_);
+  }*/
+};
+template <>
+struct ready_continuable<> {
+  template <typename Callback>
+  void operator()(Callback&& callback) && {
+    util::invoke(std::forward<Callback>(callback));
   }
-};*/
+
+  /*bool operator()(is_ready_arg_t) const noexcept {
+  return true;
+  }
+
+  void operator()(get_arg_t) && {
+  }*/
+};
 
 /*template <typename Continuation, typename Args>
 struct proxy_continuable : Continuation {