decouple take_while from observable (#293)

* Implementation of take_while operator and tests

* Refactored tests and changed documentation

* Removed 'noexcept' specifier from helper class in take_while test

* Removed 'const' specifier from not_equal_to helper class in take_while test in order to get rid of MSVC assignment operator warning.

* decouple take_while from observable

1 files changed, 6 insertions, 13 deletions

diff --git a/Rx/v2/src/rxcpp/rx-observable.hpp b/Rx/v2/src/rxcpp/rx-observable.hpp
index 1ff8c02..8033198 100644
--- a/Rx/v2/src/rxcpp/rx-observable.hpp
+++ b/Rx/v2/src/rxcpp/rx-observable.hpp
@@ -2930,22 +2930,15 @@ public:
         return  take_until(rxs::timer(when, cn), cn);
     }
 
-    /*! For the first items fulfilling the predicate from this observable emit them from the new observable that is returned.
-
-    \tparam Predicate  the type of the predicate
-
-    \param t  the predicate
-
-    \return  An observable that emits only the first items emitted by the source Observable fulfilling the predicate, or all of the items from the source observable if the predicate never returns false
-*/
-    template<class Predicate>
-    auto take_while(Predicate t) const
+    /*! @copydoc rx-take_while.hpp
+    */
+    template<class... AN>
+    auto take_while(AN&&... an) const
     /// \cond SHOW_SERVICE_MEMBERS
-    ->      observable<T,   rxo::detail::take_while<T, this_type, Predicate>>
+    -> decltype(observable_member(take_while_tag{}, *(this_type*)nullptr, std::forward<AN>(an)...))
     /// \endcond
     {
-        return  observable<T,   rxo::detail::take_while<T, this_type, Predicate>>(
-                rxo::detail::take_while<T, this_type, Predicate>(*this, t));
+        return  observable_member(take_while_tag{}, *this,                std::forward<AN>(an)...);
     }
 
     /*! Infinitely repeat this observable.