WIP Lazy coroutines

rt/result.hpp

@@ -13,7 +13,6 @@ namespace typon
   template <typename T>
   struct result
   {
-
     std::exception_ptr _exception;
     union
     {
@@ -56,14 +55,12 @@ namespace typon
       }
       return std::move(_value);
     }
-
   };
 
 
   template <typename T>
   struct result<T&>
   {
-
     T* _value;
     std::exception_ptr _exception;
 
@@ -85,16 +82,16 @@ namespace typon
       }
       return *_value;
     }
-
   };
 
 
   template <>
   struct result<void>
   {
-
     std::exception_ptr _exception;
 
+    void return_void() noexcept {}
+
     void unhandled_exception() noexcept
     {
       _exception = std::current_exception();
@@ -107,7 +104,6 @@ namespace typon
         std::rethrow_exception(_exception);
       }
     }
-
   };
 
 }

rt/task.hpp

@@ -3,7 +3,6 @@
 
 #include <coroutine>
 
-#include <promise.hpp>
 #include <result.hpp>
 
 
@@ -11,49 +10,69 @@ namespace typon
 {
 
   template <typename T = void>
-  //struct [[nodiscard]] task
-  struct task
+  struct [[nodiscard]] task
   {
     struct promise_type;
 
     std::coroutine_handle<promise_type> _coroutine;
-    result<T> _result;
 
-    struct promise_type : promise<T>
+    ~task()
+    {
+      _coroutine.destroy();
+    }
+
+    struct promise_type : result<T>
     {
 
-      // std::coroutine_handle<> _continuation;
+      std::coroutine_handle<> _continuation;
+
+      struct final_awaitable : std::suspend_always
+      {
+        template <typename Promise>
+        std::coroutine_handle<> await_suspend(std::coroutine_handle<Promise> coroutine) noexcept
+        {
+          return coroutine.promise()._continuation;
+        }
+      };
 
       task get_return_object() noexcept
       {
-        task _task { std::coroutine_handle<promise_type>::from_promise(*this), result<T> {} };
-        this->_result = std::addressof(_task._result);
-        return _task;
+        return { std::coroutine_handle<promise_type>::from_promise(*this) };
       }
 
-      std::suspend_never initial_suspend() noexcept
+      std::suspend_always initial_suspend() noexcept
       {
         return {};
       }
 
-      std::suspend_never final_suspend() noexcept
+      final_awaitable final_suspend() noexcept
       {
         return {};
       }
-
     };
 
-    // auto operator co_await() const&& noexcept
-    // {
-    //   struct awaitable
-    //   {
-    //     bool await_ready() noexcept
-    //     {
+    auto operator co_await() const&& noexcept
+    {
+      struct awaitable
+      {
+        std::coroutine_handle<promise_type> _coroutine;
+
+        bool await_ready() { return false; };
+
+        std::coroutine_handle<> await_suspend(std::coroutine_handle<> awaiting_coroutine) noexcept
+        {
+          _coroutine.promise()._continuation = awaiting_coroutine;
+          return _coroutine;
+        }
 
-    //     }
-    //   };
-    // }
+        decltype(auto) await_resume()
+        {
+          return _coroutine.promise().get();
+        }
+      };
 
+      return awaitable { _coroutine };
+    }
   };
   
 }