From 9e27dce52c3113d58d7351790d1c05887c7a2c11 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dietmar=20K=C3=BChl?= <dietmar.kuehl@me.com>
Date: Thu, 7 Aug 2025 20:59:27 +0100
Subject: [PATCH 1/3] restructuring the awaiter to cope with environments

---
 include/beman/task/detail/awaiter.hpp   | 16 +++++----
 include/beman/task/detail/handle.hpp    |  3 ++
 include/beman/task/detail/state.hpp     | 34 ++----------------
 include/beman/task/detail/state_rep.hpp | 48 +++++++++++++++++++++++++
 4 files changed, 62 insertions(+), 39 deletions(-)
 create mode 100644 include/beman/task/detail/state_rep.hpp

diff --git a/include/beman/task/detail/awaiter.hpp b/include/beman/task/detail/awaiter.hpp
index 8320ec4..eb9b861 100644
--- a/include/beman/task/detail/awaiter.hpp
+++ b/include/beman/task/detail/awaiter.hpp
@@ -6,6 +6,7 @@
 
 #include <beman/task/detail/handle.hpp>
 #include <beman/task/detail/state_base.hpp>
+#include <beman/task/detail/state_rep.hpp>
 #include <coroutine>
 #include <utility>
 
@@ -45,18 +46,21 @@ struct awaiter_op_t<Awaiter, ParentPromise, false> {
 };
 
 template <typename Value, typename Env, typename OwnPromise, typename ParentPromise>
-class awaiter : public ::beman::task::detail::state_base<Value, Env> {
+class awaiter : public ::beman::task::detail::state_base<Value, Env>, ::beman::task::detail::state_rep<Env, ::beman::task::detail::handle<OwnPromise>> {
   public:
     using stop_token_type = typename ::beman::task::detail::state_base<Value, Env>::stop_token_type;
     using scheduler_type  = typename ::beman::task::detail::state_base<Value, Env>::scheduler_type;
 
-    explicit awaiter(::beman::task::detail::handle<OwnPromise> h) : handle(::std::move(h)) {}
+    explicit awaiter(::beman::task::detail::handle<OwnPromise> h) :
+        ::beman::task::detail::state_rep<Env, ::beman::task::detail::handle<OwnPromise>>(std::move(h))
+    {
+    }
     constexpr auto await_ready() const noexcept -> bool { return false; }
     auto           await_suspend(::std::coroutine_handle<ParentPromise> parent) noexcept {
         this->scheduler.emplace(
             this->template from_env<scheduler_type>(::beman::execution::get_env(parent.promise())));
         this->parent = ::std::move(parent);
-        return this->handle.start(this);
+        return this->receiver.start(this);
     }
     auto await_resume() { return this->result_resume(); }
 
@@ -79,18 +83,16 @@ class awaiter : public ::beman::task::detail::state_base<Value, Env> {
         return this->actual_complete();
     }
     auto actual_complete() -> std::coroutine_handle<> {
-        return this->no_completion_set() ? this->parent.promise().unhandled_stopped() : ::std::move(this->parent);
+        return this->::beman::task::detail::state_base<Value, Env>::no_completion_set() ? this->parent.promise().unhandled_stopped() : ::std::move(this->parent);
     }
     auto do_get_scheduler() -> scheduler_type override { return *this->scheduler; }
     auto do_set_scheduler(scheduler_type other) -> scheduler_type override {
         return ::std::exchange(*this->scheduler, other);
     }
     auto do_get_stop_token() -> stop_token_type override { return {}; }
-    auto do_get_environment() -> Env& override { return this->env; }
+    auto do_get_environment() -> Env& override { return this->context; }
 
-    Env                                                   env;
     ::std::optional<scheduler_type>                       scheduler;
-    ::beman::task::detail::handle<OwnPromise>             handle;
     ::std::coroutine_handle<ParentPromise>                parent{};
     ::std::optional<awaiter_op_t<awaiter, ParentPromise>> reschedule{};
 };
diff --git a/include/beman/task/detail/handle.hpp b/include/beman/task/detail/handle.hpp
index 2a848d3..b2e40ab 100644
--- a/include/beman/task/detail/handle.hpp
+++ b/include/beman/task/detail/handle.hpp
@@ -32,6 +32,9 @@ class handle {
     auto release() -> ::std::coroutine_handle<P> {
         return ::std::coroutine_handle<P>::from_promise(*this->h.release());
     }
+    auto get_env() const noexcept {
+        return ::beman::execution::get_env(*this->h);
+    }
 };
 
 } // namespace beman::task::detail
diff --git a/include/beman/task/detail/state.hpp b/include/beman/task/detail/state.hpp
index df2b315..714a077 100644
--- a/include/beman/task/detail/state.hpp
+++ b/include/beman/task/detail/state.hpp
@@ -4,8 +4,9 @@
 #ifndef INCLUDED_INCLUDE_BEMAN_TASK_DETAIL_STATE
 #define INCLUDED_INCLUDE_BEMAN_TASK_DETAIL_STATE
 
-#include <beman/task/detail/state_base.hpp>
 #include <beman/task/detail/promise_type.hpp>
+#include <beman/task/detail/state_base.hpp>
+#include <beman/task/detail/state_rep.hpp>
 #include <beman/task/detail/stop_source.hpp>
 #include <type_traits>
 #include <utility>
@@ -13,37 +14,6 @@
 // ----------------------------------------------------------------------------
 
 namespace beman::task::detail {
-template <typename C, typename Receiver>
-struct state_rep {
-    std::remove_cvref_t<Receiver> receiver;
-    C                             context;
-    template <typename R>
-    state_rep(R&& r) : receiver(std::forward<R>(r)), context() {}
-};
-template <typename C, typename Receiver>
-    requires requires { C(::beman::execution::get_env(std::declval<std::remove_cvref_t<Receiver>&>())); } &&
-             (not requires(const Receiver& receiver) {
-                 typename C::template env_type<decltype(::beman::execution::get_env(receiver))>;
-             })
-struct state_rep<C, Receiver> {
-    std::remove_cvref_t<Receiver> receiver;
-    C                             context;
-    template <typename R>
-    state_rep(R&& r) : receiver(std::forward<R>(r)), context(::beman::execution::get_env(this->receiver)) {}
-};
-template <typename C, typename Receiver>
-    requires requires(const Receiver& receiver) {
-        typename C::template env_type<decltype(::beman::execution::get_env(receiver))>;
-    }
-struct state_rep<C, Receiver> {
-    using upstream_env = decltype(::beman::execution::get_env(std::declval<std::remove_cvref_t<Receiver>&>()));
-    std::remove_cvref_t<Receiver>               receiver;
-    typename C::template env_type<upstream_env> own_env;
-    C                                           context;
-    template <typename R>
-    state_rep(R&& r)
-        : receiver(std::forward<R>(r)), own_env(::beman::execution::get_env(this->receiver)), context(this->own_env) {}
-};
 
 template <typename Task, typename T, typename C, typename Receiver>
 struct state : ::beman::task::detail::state_base<T, C>, ::beman::task::detail::state_rep<C, Receiver> {
diff --git a/include/beman/task/detail/state_rep.hpp b/include/beman/task/detail/state_rep.hpp
new file mode 100644
index 0000000..250b8e8
--- /dev/null
+++ b/include/beman/task/detail/state_rep.hpp
@@ -0,0 +1,48 @@
+// include/beman/task/detail/state_rep.hpp                            -*-C++-*-
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#ifndef INCLUDED_INCLUDE_BEMAN_TASK_DETAIL_STATE_REP
+#define INCLUDED_INCLUDE_BEMAN_TASK_DETAIL_STATE_REP
+
+#include <beman/execution/execution.hpp>
+#include <utility>
+
+// ----------------------------------------------------------------------------
+
+namespace beman::task::detail {
+template <typename C, typename Receiver>
+struct state_rep {
+    std::remove_cvref_t<Receiver> receiver;
+    C                             context;
+    template <typename R>
+    state_rep(R&& r) : receiver(std::forward<R>(r)), context() {}
+};
+template <typename C, typename Receiver>
+    requires requires { C(::beman::execution::get_env(std::declval<std::remove_cvref_t<Receiver>&>())); } &&
+             (not requires(const Receiver& receiver) {
+                 typename C::template env_type<decltype(::beman::execution::get_env(receiver))>;
+             })
+struct state_rep<C, Receiver> {
+    std::remove_cvref_t<Receiver> receiver;
+    C                             context;
+    template <typename R>
+    state_rep(R&& r) : receiver(std::forward<R>(r)), context(::beman::execution::get_env(this->receiver)) {}
+};
+template <typename C, typename Receiver>
+    requires requires(const Receiver& receiver) {
+        typename C::template env_type<decltype(::beman::execution::get_env(receiver))>;
+    }
+struct state_rep<C, Receiver> {
+    using upstream_env = decltype(::beman::execution::get_env(std::declval<std::remove_cvref_t<Receiver>&>()));
+    std::remove_cvref_t<Receiver>               receiver;
+    typename C::template env_type<upstream_env> own_env;
+    C                                           context;
+    template <typename R>
+    state_rep(R&& r)
+        : receiver(std::forward<R>(r)), own_env(::beman::execution::get_env(this->receiver)), context(this->own_env) {}
+};
+}
+
+// ----------------------------------------------------------------------------
+
+#endif

From e86ea3e4af491c0ff9a770d83666fe670a08cc31 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dietmar=20K=C3=BChl?= <dietmar.kuehl@me.com>
Date: Thu, 7 Aug 2025 21:09:36 +0100
Subject: [PATCH 2/3] added a missing function to the result_type

---
 include/beman/task/detail/result_type.hpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/beman/task/detail/result_type.hpp b/include/beman/task/detail/result_type.hpp
index c74ab62..7a8bffe 100644
--- a/include/beman/task/detail/result_type.hpp
+++ b/include/beman/task/detail/result_type.hpp
@@ -162,6 +162,7 @@ class result_type<Stop, Value, ::beman::execution::completion_signatures<>> {
     auto set_value(T&& value) -> void {
         this->result.template emplace<1u>(::std::forward<T>(value));
     }
+    auto no_completion_set() const noexcept -> bool { return this->result.index() == 0u; }
 
     /**
      * \brief Call the completion function according to the current result.

From b460f9a3f003992e58b85a4f495f707878be7b47 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dietmar=20K=C3=BChl?= <dietmar.kuehl@me.com>
Date: Thu, 7 Aug 2025 21:11:39 +0100
Subject: [PATCH 3/3] clang-format

---
 include/beman/task/detail/awaiter.hpp   | 13 +++++++------
 include/beman/task/detail/handle.hpp    |  4 +---
 include/beman/task/detail/state_rep.hpp |  2 +-
 3 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/include/beman/task/detail/awaiter.hpp b/include/beman/task/detail/awaiter.hpp
index eb9b861..ab751b5 100644
--- a/include/beman/task/detail/awaiter.hpp
+++ b/include/beman/task/detail/awaiter.hpp
@@ -46,15 +46,14 @@ struct awaiter_op_t<Awaiter, ParentPromise, false> {
 };
 
 template <typename Value, typename Env, typename OwnPromise, typename ParentPromise>
-class awaiter : public ::beman::task::detail::state_base<Value, Env>, ::beman::task::detail::state_rep<Env, ::beman::task::detail::handle<OwnPromise>> {
+class awaiter : public ::beman::task::detail::state_base<Value, Env>,
+                ::beman::task::detail::state_rep<Env, ::beman::task::detail::handle<OwnPromise>> {
   public:
     using stop_token_type = typename ::beman::task::detail::state_base<Value, Env>::stop_token_type;
     using scheduler_type  = typename ::beman::task::detail::state_base<Value, Env>::scheduler_type;
 
-    explicit awaiter(::beman::task::detail::handle<OwnPromise> h) :
-        ::beman::task::detail::state_rep<Env, ::beman::task::detail::handle<OwnPromise>>(std::move(h))
-    {
-    }
+    explicit awaiter(::beman::task::detail::handle<OwnPromise> h)
+        : ::beman::task::detail::state_rep<Env, ::beman::task::detail::handle<OwnPromise>>(std::move(h)) {}
     constexpr auto await_ready() const noexcept -> bool { return false; }
     auto           await_suspend(::std::coroutine_handle<ParentPromise> parent) noexcept {
         this->scheduler.emplace(
@@ -83,7 +82,9 @@ class awaiter : public ::beman::task::detail::state_base<Value, Env>, ::beman::t
         return this->actual_complete();
     }
     auto actual_complete() -> std::coroutine_handle<> {
-        return this->::beman::task::detail::state_base<Value, Env>::no_completion_set() ? this->parent.promise().unhandled_stopped() : ::std::move(this->parent);
+        return this->::beman::task::detail::state_base<Value, Env>::no_completion_set()
+                   ? this->parent.promise().unhandled_stopped()
+                   : ::std::move(this->parent);
     }
     auto do_get_scheduler() -> scheduler_type override { return *this->scheduler; }
     auto do_set_scheduler(scheduler_type other) -> scheduler_type override {
diff --git a/include/beman/task/detail/handle.hpp b/include/beman/task/detail/handle.hpp
index b2e40ab..28d9c3d 100644
--- a/include/beman/task/detail/handle.hpp
+++ b/include/beman/task/detail/handle.hpp
@@ -32,9 +32,7 @@ class handle {
     auto release() -> ::std::coroutine_handle<P> {
         return ::std::coroutine_handle<P>::from_promise(*this->h.release());
     }
-    auto get_env() const noexcept {
-        return ::beman::execution::get_env(*this->h);
-    }
+    auto get_env() const noexcept { return ::beman::execution::get_env(*this->h); }
 };
 
 } // namespace beman::task::detail
diff --git a/include/beman/task/detail/state_rep.hpp b/include/beman/task/detail/state_rep.hpp
index 250b8e8..abb2baa 100644
--- a/include/beman/task/detail/state_rep.hpp
+++ b/include/beman/task/detail/state_rep.hpp
@@ -41,7 +41,7 @@ struct state_rep<C, Receiver> {
     state_rep(R&& r)
         : receiver(std::forward<R>(r)), own_env(::beman::execution::get_env(this->receiver)), context(this->own_env) {}
 };
-}
+} // namespace beman::task::detail
 
 // ----------------------------------------------------------------------------