Manually merge PR from wravery, closes #309

doc/Changelog.md

@@ -2,7 +2,7 @@
 
 ## 3.2.6
 
-Released 2022-??-??
+Released 2022-06-29
 
 * Made `unwind()` optional for parse tree nodes.
 * Fixed `demangle()` for MSVC, again.

include/tao/pegtl/internal/unwind_guard.hpp

@@ -0,0 +1,39 @@
+// Copyright (c) 2014-2022 Dr. Colin Hirsch and Daniel Frey
+// Please see LICENSE for license or visit https://github.com/taocpp/PEGTL/
+
+#ifndef TAO_PEGTL_INTERNAL_UNWIND_GUARD_HPP
+#define TAO_PEGTL_INTERNAL_UNWIND_GUARD_HPP
+
+#include "../config.hpp"
+
+#include <optional>
+#include <utility>
+
+namespace TAO_PEGTL_NAMESPACE::internal
+{
+   template< typename Unwind >
+   struct unwind_guard
+   {
+      explicit unwind_guard( Unwind&& unwind_impl )
+         : unwind( std::move( unwind_impl ) )
+      {}
+
+      ~unwind_guard()
+      {
+         if( unwind ) {
+            ( *unwind )();
+         }
+      }
+
+      unwind_guard( const unwind_guard& ) = delete;
+      unwind_guard( unwind_guard&& ) noexcept = delete;
+
+      unwind_guard& operator=( const unwind_guard& ) = delete;
+      unwind_guard& operator=( unwind_guard&& ) noexcept = delete;
+
+      std::optional< Unwind > unwind;
+   };
+
+}  // namespace TAO_PEGTL_NAMESPACE::internal
+
+#endif

include/tao/pegtl/match.hpp

@@ -19,6 +19,7 @@
 #include "internal/marker.hpp"
 #include "internal/missing_apply.hpp"
 #include "internal/missing_apply0.hpp"
+#include "internal/unwind_guard.hpp"
 
 #if defined( _MSC_VER )
 #pragma warning( push )
@@ -72,13 +73,12 @@ namespace TAO_PEGTL_NAMESPACE
       {
 #if defined( __cpp_exceptions )
          if constexpr( has_unwind< Control< Rule >, void, const ParseInput&, States... > ) {
-            try {
-               return match_no_control< Rule, A, M, Action, Control >( in, st... );
-            }
-            catch( ... ) {
+            unwind_guard ug( [ & ] {
                Control< Rule >::unwind( static_cast< const ParseInput& >( in ), st... );
-               throw;
-            }
+            } );
+            const auto result = match_no_control< Rule, A, M, Action, Control >( in, st... );
+            ug.unwind.reset();
+            return result;
          }
          else {
             return match_no_control< Rule, A, M, Action, Control >( in, st... );