1 files changed, 91 insertions, 17 deletions

diff --git a/Rx/v2/src/rxcpp/operators/rx-switch_if_empty.hpp b/Rx/v2/src/rxcpp/operators/rx-switch_if_empty.hpp
index cf51109..b9bab52 100644
--- a/Rx/v2/src/rxcpp/operators/rx-switch_if_empty.hpp
+++ b/Rx/v2/src/rxcpp/operators/rx-switch_if_empty.hpp
@@ -2,6 +2,21 @@
 
 #pragma once
 
+/*! \file rx-switch_if_empty.hpp
+
+    \brief If the source Observable terminates without emitting any items, emits items from a backup Observable.
+
+    \tparam BackupSource the type of the backup observable.
+
+    \param t a backup observable that is used if the source observable is empty.
+
+    \return Observable that emits items from a backup observable if the source observable is empty.
+
+    \sample
+    \snippet switch_if_empty.cpp switch_if_empty sample
+    \snippet output.txt switch_if_empty sample
+*/
+
 #if !defined(RXCPP_OPERATORS_RX_SWITCH_IF_EMPTY_HPP)
 #define RXCPP_OPERATORS_RX_SWITCH_IF_EMPTY_HPP
 
@@ -13,6 +28,16 @@ namespace operators {
 
 namespace detail {
 
+template<class... AN>
+struct switch_if_empty_invalid_arguments {};
+
+template<class... AN>
+struct switch_if_empty_invalid : public rxo::operator_base<switch_if_empty_invalid_arguments<AN...>> {
+    using type = observable<switch_if_empty_invalid_arguments<AN...>, switch_if_empty_invalid<AN...>>;
+};
+template<class... AN>
+using switch_if_empty_invalid_t = typename switch_if_empty_invalid<AN...>::type;
+
 template<class T, class BackupSource>
 struct switch_if_empty
 {
@@ -75,30 +100,79 @@ struct switch_if_empty
     }
 };
 
-template<class BackupSource>
-class switch_if_empty_factory
-{
-    typedef rxu::decay_t<BackupSource> backup_source_type;
-    backup_source_type backup;
-public:
-    switch_if_empty_factory(backup_source_type b) : backup(std::move(b)) {}
-    template<class Observable>
-    auto operator()(Observable&& source)
-        -> decltype(source.template lift<rxu::value_type_t<rxu::decay_t<Observable>>>(switch_if_empty<rxu::value_type_t<rxu::decay_t<Observable>>, backup_source_type>(backup))) {
-        return      source.template lift<rxu::value_type_t<rxu::decay_t<Observable>>>(switch_if_empty<rxu::value_type_t<rxu::decay_t<Observable>>, backup_source_type>(backup));
-    }
-};
+}
 
+/*! @copydoc rx-switch_if_empty.hpp
+*/
+template<class... AN>
+auto switch_if_empty(AN&&... an)
+    ->      operator_factory<switch_if_empty_tag, AN...> {
+     return operator_factory<switch_if_empty_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
 }
 
-template<class BackupSource>
-auto switch_if_empty(BackupSource&& b)
-    ->      detail::switch_if_empty_factory<BackupSource> {
-    return  detail::switch_if_empty_factory<BackupSource>(std::forward<BackupSource>(b));
+/*! \brief If the source Observable terminates without emitting any items, emits a default item and completes.
+
+    \tparam Value the type of the value to emit.
+
+    \param v the default value to emit.
+
+    \return Observable that emits the specified default item if the source observable is empty.
+
+    \sample
+    \snippet default_if_empty.cpp default_if_empty sample
+    \snippet output.txt default_if_empty sample
+*/
+template<class... AN>
+auto default_if_empty(AN&&... an)
+    ->      operator_factory<default_if_empty_tag, AN...> {
+     return operator_factory<default_if_empty_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
 }
 
 }
 
+template<>
+struct member_overload<switch_if_empty_tag>
+{
+    template<class Observable, class BackupSource,
+        class Enabled = rxu::enable_if_all_true_type_t<
+            all_observables<Observable, BackupSource>>,
+        class SourceValue = rxu::value_type_t<Observable>,
+        class SwitchIfEmpty = rxo::detail::switch_if_empty<SourceValue, rxu::decay_t<BackupSource>>>
+    static auto member(Observable&& o, BackupSource&& b)
+        -> decltype(o.template lift<SourceValue>(SwitchIfEmpty(std::forward<BackupSource>(b)))) {
+        return      o.template lift<SourceValue>(SwitchIfEmpty(std::forward<BackupSource>(b)));
+    }
+
+    template<class... AN>
+    static operators::detail::switch_if_empty_invalid_t<AN...> member(AN...) {
+        std::terminate();
+        return {};
+        static_assert(sizeof...(AN) == 10000, "switch_if_empty takes (BackupSource)");
+    }
+};
+
+template<>
+struct member_overload<default_if_empty_tag>
+{
+    template<class Observable, class Value,
+        class Enabled = rxu::enable_if_all_true_type_t<
+            is_observable<Observable>>,
+        class SourceValue = rxu::value_type_t<Observable>,
+        class BackupSource = decltype(rxs::from(std::declval<SourceValue>())),
+        class DefaultIfEmpty = rxo::detail::switch_if_empty<SourceValue, BackupSource>>
+    static auto member(Observable&& o, Value v)
+        -> decltype(o.template lift<SourceValue>(DefaultIfEmpty(rxs::from(std::move(v))))) {
+        return      o.template lift<SourceValue>(DefaultIfEmpty(rxs::from(std::move(v))));
+    }
+
+    template<class... AN>
+    static operators::detail::switch_if_empty_invalid_t<AN...> member(AN...) {
+        std::terminate();
+        return {};
+        static_assert(sizeof...(AN) == 10000, "default_if_empty takes (Value)");
+    }
+};
+
 }
 
 #endif