Add support for retrieving generator's element as string

src/catch2/interfaces/catch_interfaces_generatortracker.cpp

@@ -0,0 +1,32 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE_1_0.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/interfaces/catch_interfaces_generatortracker.hpp>
+#include <string>
+
+namespace Catch {
+    namespace Generators {
+
+        bool GeneratorUntypedBase::countedNext() {
+            auto ret = next();
+            if ( ret ) {
+                m_stringReprCache.clear();
+                ++m_currentElementIndex;
+            }
+            return ret;
+        }
+
+        StringRef GeneratorUntypedBase::currentElementAsString() const {
+            if ( m_stringReprCache.empty() ) {
+                m_stringReprCache = stringifyImpl();
+            }
+            return m_stringReprCache;
+        }
+
+    } // namespace Generators
+} // namespace Catch