diff --git a/cmake/macros/group_sources.cmake b/cmake/macros/group_sources.cmake
index c0de7df..9c2bebf 100644
--- a/cmake/macros/group_sources.cmake
+++ b/cmake/macros/group_sources.cmake
@@ -20,39 +20,41 @@
 # SOFTWARE.
 
 set(WITH_SOURCE_TREE "hierarchical")
-macro(group_sources dir)
+macro(group_sources)
   # Skip this if WITH_SOURCE_TREE is not set (empty string).
   if (NOT ${WITH_SOURCE_TREE} STREQUAL "")
-    # Include all header and c files
-    file(GLOB_RECURSE elements RELATIVE ${dir} *.h *.hpp *.inl *.inc *.c *.cpp *.cc)
+    foreach(dir ${ARGN})
+      # Include all header and c files
+      file(GLOB_RECURSE elements RELATIVE ${dir} ${dir}/*)
 
-    foreach(element ${elements})
-      # Extract filename and directory
-      get_filename_component(element_name ${element} NAME)
-      get_filename_component(element_dir ${element} DIRECTORY)
+      foreach(element ${elements})
+        # Extract filename and directory
+        get_filename_component(element_name ${element} NAME)
+        get_filename_component(element_dir ${element} DIRECTORY)
 
-      if (NOT ${element_dir} STREQUAL "")
-        # If the file is in a subdirectory use it as source group.
-        if (${WITH_SOURCE_TREE} STREQUAL "flat")
-          # Build flat structure by using only the first subdirectory.
-          string(FIND ${element_dir} "/" delemiter_pos)
-          if (NOT ${delemiter_pos} EQUAL -1)
-            string(SUBSTRING ${element_dir} 0 ${delemiter_pos} group_name)
-            source_group("${group_name}" FILES ${dir}/${element})
+        if (NOT ${element_dir} STREQUAL "")
+          # If the file is in a subdirectory use it as source group.
+          if (${WITH_SOURCE_TREE} STREQUAL "flat")
+            # Build flat structure by using only the first subdirectory.
+            string(FIND ${element_dir} "/" delemiter_pos)
+            if (NOT ${delemiter_pos} EQUAL -1)
+              string(SUBSTRING ${element_dir} 0 ${delemiter_pos} group_name)
+              source_group("${group_name}" FILES ${dir}/${element})
+            else()
+              # Build hierarchical structure.
+              # File is in root directory.
+              source_group("${element_dir}" FILES ${dir}/${element})
+            endif()
           else()
-            # Build hierarchical structure.
-            # File is in root directory.
-            source_group("${element_dir}" FILES ${dir}/${element})
+            # Use the full hierarchical structure to build source_groups.
+            string(REPLACE "/" "\\" group_name ${element_dir})
+            source_group("${group_name}" FILES ${dir}/${element})
           endif()
         else()
-          # Use the full hierarchical structure to build source_groups.
-          string(REPLACE "/" "\\" group_name ${element_dir})
-          source_group("${group_name}" FILES ${dir}/${element})
+          # If the file is in the root directory, place it in the root source_group.
+          source_group("\\" FILES ${dir}/${element})
         endif()
-      else()
-        # If the file is in the root directory, place it in the root source_group.
-        source_group("\\" FILES ${dir}/${element})
-      endif()
+      endforeach()
     endforeach()
   endif()
 endmacro()
diff --git a/include/continuable/continuable-operations.hpp b/include/continuable/continuable-operations.hpp
new file mode 100644
index 0000000..17ea49f
--- /dev/null
+++ b/include/continuable/continuable-operations.hpp
@@ -0,0 +1,40 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_OPERATIONS_HPP_INCLUDED
+#define CONTINUABLE_OPERATIONS_HPP_INCLUDED
+
+/// \defgroup Operations Operations
+/// provides functions to work with asynchronous control flows.
+
+#include <continuable/operations/async.hpp>
+#include <continuable/operations/loop.hpp>
+
+#endif // CONTINUABLE_OPERATIONS_HPP_INCLUDED
diff --git a/include/continuable/continuable.hpp b/include/continuable/continuable.hpp
index 214b220..cbbc43a 100644
--- a/include/continuable/continuable.hpp
+++ b/include/continuable/continuable.hpp
@@ -48,6 +48,7 @@ namespace cti {}
 #include <continuable/continuable-base.hpp>
 #include <continuable/continuable-connections.hpp>
 #include <continuable/continuable-coroutine.hpp>
+#include <continuable/continuable-operations.hpp>
 #include <continuable/continuable-primitives.hpp>
 #include <continuable/continuable-promise-base.hpp>
 #include <continuable/continuable-promisify.hpp>
diff --git a/include/continuable/detail/operations/async.hpp b/include/continuable/detail/operations/async.hpp
new file mode 100644
index 0000000..71e1fd1
--- /dev/null
+++ b/include/continuable/detail/operations/async.hpp
@@ -0,0 +1,47 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_OPERATIONS_ASYNC_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_OPERATIONS_ASYNC_HPP_INCLUDED
+
+#include <continuable/continuable-base.hpp>
+
+namespace cti {
+namespace detail {
+namespace operations {
+template <typename Callable, typename... Args>
+auto async(Callable&& callable, Args&&... args) {
+}
+} // namespace operations
+
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_OPERATIONS_ASYNC_HPP_INCLUDED
diff --git a/include/continuable/detail/operations/loop.hpp b/include/continuable/detail/operations/loop.hpp
new file mode 100644
index 0000000..6088f0f
--- /dev/null
+++ b/include/continuable/detail/operations/loop.hpp
@@ -0,0 +1,126 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_DETAIL_OPERATIONS_LOOP_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_OPERATIONS_LOOP_HPP_INCLUDED
+
+#include <cassert>
+#include <memory>
+#include <tuple>
+#include <type_traits>
+#include <continuable/continuable-base.hpp>
+#include <continuable/continuable-result.hpp>
+#include <continuable/detail/utility/traits.hpp>
+#include <continuable/detail/utility/util.hpp>
+
+namespace cti {
+namespace detail {
+template <typename T>
+struct loop_trait {
+  static_assert(!std::is_same<T, T>::value,
+                "The callable passed to cti::loop must always return a "
+                "cti::continuable_base which resolves to a cti::result.");
+};
+
+template <typename Continuation, typename... Args>
+struct loop_trait<continuable_base<Continuation, //
+                                   signature_arg_t<result<Args...>>>> {
+  template <typename Callable>
+  static auto make(Callable&& callable) {
+    return make_continuable<Args...>(std::forward<Callable>(callable));
+  }
+};
+template <typename Continuation>
+struct loop_trait<continuable_base<Continuation, signature_arg_t<result<>>>> {
+  template <typename Callable>
+  static auto make(Callable&& callable) {
+    return make_continuable<void>(std::forward<Callable>(callable));
+  }
+};
+
+namespace operations {
+template <typename Promise, typename Callable, typename ArgsTuple>
+class loop_frame : public std::enable_shared_from_this<
+                       loop_frame<Promise, Callable, ArgsTuple>> {
+  Promise promise_;
+  Callable callable_;
+  ArgsTuple args_;
+
+public:
+  void loop() {
+    traits::unpack(
+        [&callable_](auto&&... args) {
+          util::invoke(callable_, std::forward<decltype(args)>(args)...)
+              .then([me = this->shared_from_this()](auto&& result) {
+                if (result.is_empty()) {
+                  me->loop();
+                } else if (result.is_value()) {
+                  traits::unpack(std::move(promise_), result);
+                } else {
+                  assert(result.is_exception());
+                  traits::unpack(std::move(promise_), exception_arg_t{},
+                                 result.get_exception());
+                }
+              });
+        },
+        args_);
+  }
+};
+
+template <typename Promise, typename Callable, typename ArgsTuple>
+auto make_loop_frame(Promise&& promise, Callable&& callable,
+                     ArgsTuple&& args_tuple) {
+  using frame_t =
+      loop_frame<traits::unrefcv_t<Promise>, traits::unrefcv_t<Callable>,
+                 traits::unrefcv_t<ArgsTuple>>;
+
+  return std::make_shared<frame_t>(std::forward<Promise>(promise),
+                                   std::forward<Callable>(callable),
+                                   std::forward<ArgsTuple>(args_tuple));
+}
+
+template <typename Callable, typename... Args>
+auto loop(Callable&& callable, Args&&... args) {
+  using invocation_result_t =
+      decltype(util::invoke(callable, args...).finish());
+  using trait_t = loop_trait<invocation_result_t>;
+  return trait_t::make([callable = std::forward<decltype(callable)>(callable),
+                        args = std::make_tuple(std::forward<decltype(args)>(
+                            args)...)](auto&& promise) mutable {
+    // Do the actual looping
+    auto frame = make_loop_frame(std::forward<decltype(promise)>(promise));
+    frame->loop();
+  });
+}
+} // namespace operations
+} // namespace detail
+} // namespace cti
+
+#endif // CONTINUABLE_DETAIL_OPERATIONS_LOOP_HPP_INCLUDED
diff --git a/include/continuable/operations/async.hpp b/include/continuable/operations/async.hpp
new file mode 100644
index 0000000..02320c7
--- /dev/null
+++ b/include/continuable/operations/async.hpp
@@ -0,0 +1,49 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_OPERATIONS_ASYNC_HPP_INCLUDED
+#define CONTINUABLE_OPERATIONS_ASYNC_HPP_INCLUDED
+
+#include <utility>
+#include <continuable/detail/operations/async.hpp>
+
+namespace cti {
+/// \ingroup Operations
+/// \{
+
+template <typename Callable, typename... Args>
+auto async(Callable&& callable, Args&&... args) {
+  return detail::operations::async(std::forward<Callable>(callable),
+                                   std::forward<Args>(args)...);
+}
+/// \}
+} // namespace cti
+
+#endif // CONTINUABLE_OPERATIONS_ASYNC_HPP_INCLUDED
diff --git a/include/continuable/operations/loop.hpp b/include/continuable/operations/loop.hpp
new file mode 100644
index 0000000..649287b
--- /dev/null
+++ b/include/continuable/operations/loop.hpp
@@ -0,0 +1,49 @@
+
+/*
+
+                        /~` _  _ _|_. _     _ |_ | _
+                        \_,(_)| | | || ||_|(_||_)|(/_
+
+                    https://github.com/Naios/continuable
+                                   v4.0.0
+
+  Copyright(c) 2015 - 2019 Denis Blank <denis.blank at outlook dot com>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files(the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions :
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+**/
+
+#ifndef CONTINUABLE_OPERATIONS_LOOP_HPP_INCLUDED
+#define CONTINUABLE_OPERATIONS_LOOP_HPP_INCLUDED
+
+#include <utility>
+#include <continuable/detail/operations/loop.hpp>
+
+namespace cti {
+/// \ingroup Operations
+/// \{
+
+template <typename Callable, typename... Args>
+auto loop(Callable&& callable, Args&&... args) {
+  return detail::operations::loop(std::forward<Callable>(callable),
+                                  std::forward<Args>(args)...);
+}
+/// \}
+} // namespace cti
+
+#endif // CONTINUABLE_OPERATIONS_LOOP_HPP_INCLUDED
diff --git a/test/playground/CMakeLists.txt b/test/playground/CMakeLists.txt
index 027b3ed..0109f99 100644
--- a/test/playground/CMakeLists.txt
+++ b/test/playground/CMakeLists.txt
@@ -1,34 +1,16 @@
-set(INCLUDE_DIR ${CMAKE_SOURCE_DIR}/include/continuable)
+set(INCLUDE_DIR ${CMAKE_SOURCE_DIR}/include)
 
-file(GLOB LIB_SOURCES CONFIGURE_DEPENDS ${INCLUDE_DIR}/*.hpp)
-file(GLOB LIB_SOURCES_DETAIL CONFIGURE_DEPENDS ${INCLUDE_DIR}/detail/*.hpp)
-file(GLOB LIB_SOURCES_DETAIL_CONNECTIONS CONFIGURE_DEPENDS ${INCLUDE_DIR}/detail/connection/*.hpp)
-file(GLOB LIB_SOURCES_DETAIL_CORE CONFIGURE_DEPENDS ${INCLUDE_DIR}/detail/core/*.hpp)
-file(GLOB LIB_SOURCES_DETAIL_OTHER CONFIGURE_DEPENDS ${INCLUDE_DIR}/detail/other/*.hpp)
-file(GLOB LIB_SOURCES_DETAIL_TRAVERSAL CONFIGURE_DEPENDS ${INCLUDE_DIR}/detail/traversal/*.hpp)
-file(GLOB LIB_SOURCES_DETAIL_UTILITY CONFIGURE_DEPENDS ${INCLUDE_DIR}/detail/utility/*.hpp)
+file(GLOB_RECURSE LIB_SOURCES CONFIGURE_DEPENDS ${INCLUDE_DIR}/*.hpp)
 
 set(TEST
   ${CMAKE_CURRENT_LIST_DIR}/test-playground.cpp)
 
 add_executable(test-playground
   ${LIB_SOURCES}
-  ${LIB_SOURCES_DETAIL}
-  ${LIB_SOURCES_DETAIL_CONNECTIONS}
-  ${LIB_SOURCES_DETAIL_CORE}
-  ${LIB_SOURCES_DETAIL_OTHER}
-  ${LIB_SOURCES_DETAIL_TRAVERSAL}
-  ${LIB_SOURCES_DETAIL_UTILITY}
   ${TEST})
 
-source_group(continuable FILES ${LIB_SOURCES})
-source_group(continuable\\detail FILES ${LIB_SOURCES_DETAIL})
-source_group(continuable\\detail\\connections FILES ${LIB_SOURCES_DETAIL_CONNECTIONS})
-source_group(continuable\\detail\\core FILES ${LIB_SOURCES_DETAIL_CORE})
-source_group(continuable\\detail\\other FILES ${LIB_SOURCES_DETAIL_OTHER})
-source_group(continuable\\detail\\traversal FILES ${LIB_SOURCES_DETAIL_TRAVERSAL})
-source_group(continuable\\detail\\utility FILES ${LIB_SOURCES_DETAIL_UTILITY})
-source_group(test FILES ${TEST})
+group_sources(${CMAKE_CURRENT_LIST_DIR}
+              ${CMAKE_SOURCE_DIR}/include/)
 
 target_link_libraries(test-playground
   PRIVATE