Async: change syntax of callables

We now pass our own Async::Future to each task, instead of expecting tasks
to return their future. This allows us to re-use the same Future for repeated
invocations, like in the Each task.

1 files changed, 20 insertions, 1 deletions

diff --git a/async/src/async_impl.h b/async/src/async_impl.h
index 46bc25d..7b5c140 100644
--- a/async/src/async_impl.h
+++ b/async/src/async_impl.h
@@ -26,7 +26,26 @@
 
 namespace Async {
 
+namespace detail {
+
+template<typename T>
+struct identity
+{
+    typedef T type;
+};
+
+template<typename T, typename Enable = void>
+struct isIterable {
+    enum { value = 0 };
+};
+
+template<typename T>
+struct isIterable<T, typename std::conditional<false, typename T::iterator, void>::type> {
+    enum { value = 1 };
+};
+
+} // namespace Detail
 
 } // namespace Async
 
-#endif // ASYNC_IMPL_H
\ No newline at end of file
+#endif // ASYNC_IMPL_H