improve the STDEXEC_TRY and STDEXEC_CATCH portability macros (#1549)

Author: ericniebler

.clang-format

@@ -90,7 +90,9 @@ Macros: [
   'STDEXEC_IMMOVABLE_NO_UNIQUE_ADDRESS=[[no_unique_address]]',
   'STDEXEC_MISSING_MEMBER(X,Y)=true',
   'STDEXEC_DEFINE_MEMBER(X)=void foo() {}',
-  'STDEXEC_AUTO_RETURN(...)=->decltype(auto){ return __VA_ARGS__; }'
+  'STDEXEC_AUTO_RETURN(...)=->decltype(auto){ return __VA_ARGS__; }',
+  'STDEXEC_TRY(...)=try { __VA_ARGS__ }',
+  'STDEXEC_CATCH(...)=catch __VA_ARGS__',
 ]
 MaxEmptyLinesToKeep: 2
 NamespaceIndentation: All

include/stdexec/__detail/__config.hpp

@@ -523,19 +523,34 @@ namespace stdexec {
 #  include <cuda_runtime_api.h>
 #endif
 
+// The following macros are used to conditionally compile exception handling code. They
+// are used in the same way as `try` and `catch` blocks, but they allow for different
+// behavior based on whether exceptions are enabled or not, and whether the code is being
+// compiled for device or not.
+//
+// Usage:
+//   STDEXEC_TRY({
+//     ...                               // Code that may throw an exception
+//   })
+//   STDEXEC_CATCH_OR((cuda_error& e) {  // Handle CUDA exceptions
+//     ...
+//   })
+//   STDEXEC_CATCH((...) {               // Handle any other exceptions
+//     ...
+//   })
 // clang-format off
 #if STDEXEC_NO_EXCEPTIONS() || (STDEXEC_CUDA_COMPILATION() && defined(__CUDA_ARCH__))
-#  define STDEXEC_TRY
-#  define STDEXEC_CATCH(...) STDEXEC_CATCH_I
-#  define STDEXEC_CATCH_I(...)
+#  define STDEXEC_TRY(...) { __VA_ARGS__ }
+#  define STDEXEC_CATCH(...)
+#  define STDEXEC_CATCH_OR(...)
 #elif STDEXEC_CUDA_COMPILATION() && STDEXEC_NVHPC()
-#  define STDEXEC_TRY if target (nv::target::is_host) { try
-#  define STDEXEC_CATCH(...) catch(__VA_ARGS__) STDEXEC_CATCH_I
-#  define STDEXEC_CATCH_I(...) { __VA_ARGS__ } } else { __VA_ARGS__ }
+#  define STDEXEC_TRY(...) if target (nv::target::is_device) { __VA_ARGS__ } else { try { __VA_ARGS__ }
+#  define STDEXEC_CATCH(...) catch __VA_ARGS__ }
+#  define STDEXEC_CATCH_OR(...) catch __VA_ARGS__
 #else
-#  define STDEXEC_TRY try
-#  define STDEXEC_CATCH(...) catch(__VA_ARGS__) STDEXEC_CATCH_I
-#  define STDEXEC_CATCH_I(...) { __VA_ARGS__ }
+#  define STDEXEC_TRY(...) try { __VA_ARGS__ }
+#  define STDEXEC_CATCH(...) catch __VA_ARGS__
+#  define STDEXEC_CATCH_OR(...) catch __VA_ARGS__
 #endif
 // clang-format on
 

include/stdexec/__detail/__receivers.hpp

@@ -192,18 +192,20 @@ namespace stdexec {
   template <class _Receiver, class _Fun, class... _As>
   STDEXEC_ATTRIBUTE(host, device)
   void __set_value_invoke(_Receiver&& __rcvr, _Fun&& __fun, _As&&... __as) noexcept {
-    STDEXEC_TRY {
+    STDEXEC_TRY({
       if constexpr (same_as<void, __invoke_result_t<_Fun, _As...>>) {
         __invoke(static_cast<_Fun&&>(__fun), static_cast<_As&&>(__as)...);
         stdexec::set_value(static_cast<_Receiver&&>(__rcvr));
       } else {
-        set_value(
+        stdexec::set_value(
           static_cast<_Receiver&&>(__rcvr),
           __invoke(static_cast<_Fun&&>(__fun), static_cast<_As&&>(__as)...));
       }
-    }
-    STDEXEC_CATCH(...)(if constexpr (!__nothrow_invocable<_Fun, _As...>) {
-      stdexec::set_error(static_cast<_Receiver&&>(__rcvr), std::current_exception());
+    })
+    STDEXEC_CATCH((...) { //
+      if constexpr (!__nothrow_invocable<_Fun, _As...>) {
+        stdexec::set_error(static_cast<_Receiver&&>(__rcvr), std::current_exception());
+      }
     })
   }
 

test/nvexec/let_stopped.cpp

@@ -39,7 +39,7 @@ namespace {
   }
 
   TEST_CASE(
-    "let_stopped can preceed a sender without values",
+    "nvexec let_stopped can preceed a sender without values",
     "[cuda][stream][adaptors][let_stopped]") {
     nvexec::stream_context stream_ctx{};
 

test/nvexec/upon_error.cpp

@@ -38,7 +38,7 @@ namespace {
   }
 
   TEST_CASE(
-    "upon_error can preceed a sender without values",
+    "nvexec upon_error can preceed a sender without values",
     "[cuda][stream][adaptors][upon_error]") {
     nvexec::stream_context stream_ctx{};
 
@@ -62,7 +62,7 @@ namespace {
   }
 
   TEST_CASE(
-    "upon_error can succeed a sender without values",
+    "nvexec upon_error can succeed a sender without values",
     "[cuda][stream][adaptors][upon_error]") {
     nvexec::stream_context stream_ctx{};