Use old namespace macro

src/util/streamable_generator.h

@@ -3,22 +3,18 @@
 #include <exception>
 #include <sstream>
 
-// coroutines are still experimental in clang, adapt the appropriate namespaces.
+// coroutines are still experimental in clang, adapt the appropriate
+// namespaces.
 #ifdef __clang__
 #include <experimental/coroutine>
+namespace qlever_stdOrExp = std::experimental;
 #else
 #include <coroutine>
+namespace qlever_stdOrExp = std;
 #endif
 
 namespace ad_utility::stream_generator {
 
-// coroutines are still experimental in clang, adapt the appropriate namespaces.
-#ifdef __clang__
-using std::suspend_always = std::experimental::suspend_always;
-using std::suspend_never = std::experimental::suspend_never;
-using std::coroutine_handle = std::experimental::coroutine_handle;
-#endif
-
 template <typename T>
 concept Streamable = requires(T x, std::ostream& os) {
   os << x;
@@ -33,7 +29,8 @@ class suspend_sometimes {
  public:
   explicit suspend_sometimes(const bool suspend) : suspend(suspend) {}
   bool await_ready() const noexcept { return !suspend; }
-  constexpr void await_suspend(std::coroutine_handle<>) const noexcept {}
+  constexpr void await_suspend(
+      qlever_stdOrExp::coroutine_handle<>) const noexcept {}
   constexpr void await_resume() const noexcept {}
 };
 
@@ -47,8 +44,12 @@ class stream_generator_promise {
 
   stream_generator get_return_object() noexcept;
 
-  constexpr std::suspend_always initial_suspend() const noexcept { return {}; }
-  constexpr std::suspend_always final_suspend() const noexcept { return {}; }
+  constexpr qlever_stdOrExp::suspend_always initial_suspend() const noexcept {
+    return {};
+  }
+  constexpr qlever_stdOrExp::suspend_always final_suspend() const noexcept {
+    return {};
+  }
 
   template <Streamable T>
   suspend_sometimes yield_value(T&& value) noexcept {
@@ -75,7 +76,7 @@ class stream_generator_promise {
 
   // Don't allow any use of 'co_await' inside the generator coroutine.
   template <typename U>
-  std::suspend_never await_transform(U&& value) = delete;
+  qlever_stdOrExp::suspend_never await_transform(U&& value) = delete;
 
   void rethrow_if_exception() {
     if (m_exception) {
@@ -139,15 +140,16 @@ class [[nodiscard]] stream_generator {
   friend class detail::stream_generator_promise;
 
   explicit stream_generator(
-      std::coroutine_handle<promise_type> coroutine) noexcept
+      qlever_stdOrExp::coroutine_handle<promise_type> coroutine) noexcept
       : m_coroutine(coroutine) {}
 
-  std::coroutine_handle<promise_type> m_coroutine;
+  qlever_stdOrExp::coroutine_handle<promise_type> m_coroutine;
 };
 
 namespace detail {
 inline stream_generator stream_generator_promise::get_return_object() noexcept {
-  using coroutine_handle = std::coroutine_handle<stream_generator_promise>;
+  using coroutine_handle =
+      qlever_stdOrExp::coroutine_handle<stream_generator_promise>;
   return stream_generator{coroutine_handle::from_promise(*this)};
 }
 }  // namespace detail