Add invoke and apply to TaggedContainers.hpp

sxs-collaboration · Feb 15, 2023 · f37d6ac · f37d6ac
1 parent a7fdeee
commit f37d6ac
Show file tree

Hide file tree

Showing 2 changed files with 69 additions and 0 deletions.
diff --git a/src/DataStructures/TaggedContainers.hpp b/src/DataStructures/TaggedContainers.hpp
@@ -78,3 +78,50 @@ gsl::not_null<typename Tag::type*> get(
   }
 }
 /// @}
+
+namespace detail {
+template <typename Callable, typename T, typename... Args,
+          typename... ReturnTags, typename... ArgumentTags>
+auto apply_impl(const gsl::not_null<T*> return_args,
+                tmpl::list<ReturnTags...> /*meta*/,
+                tmpl::list<ArgumentTags...> /*meta*/, Callable&& fn,
+                const Args&... args) {
+  return fn.apply(get<ReturnTags>(return_args)...,
+                  get<ArgumentTags>(args...)...);
+}
+
+template <typename Callable, typename T, typename... Args,
+          typename... ReturnTags, typename... ArgumentTags>
+auto invoke_impl(const gsl::not_null<T*> return_args,
+                 tmpl::list<ReturnTags...> /*meta*/,
+                 tmpl::list<ArgumentTags...> /*meta*/, Callable&& fn,
+                 const Args&... args) {
+  return fn(get<ReturnTags>(return_args)..., get<ArgumentTags>(args...)...);
+}
+}  // namespace detail
+
+/*!
+ * \brief Call
+ * `fn.apply(get<Callable::return_tags>(return_args)...,
+ * get<Callable::argument_tags>(args...))`
+ */
+template <typename Callable, typename T, typename... Args>
+auto apply(const gsl::not_null<T*> return_args, Callable&& fn,
+           const Args&... args) {
+  return detail::apply_impl(return_args, typename Callable::return_tags{},
+                            typename Callable::argument_tags{},
+                            std::forward<Callable>(fn), args...);
+}
+
+/*!
+ * \brief Call
+ * `fn(get<Callable::return_tags>(return_args)...,
+ * get<Callable::argument_tags>(args...))`
+ */
+template <typename Callable, typename T, typename... Args>
+auto invoke(const gsl::not_null<T*> return_args, Callable&& fn,
+            const Args&... args) {
+  return detail::invoke_impl(return_args, typename Callable::return_tags{},
+                             typename Callable::argument_tags{},
+                             std::forward<Callable>(fn), args...);
+}
diff --git a/tests/Unit/DataStructures/Test_TaggedContainers.cpp b/tests/Unit/DataStructures/Test_TaggedContainers.cpp
@@ -27,6 +27,21 @@ struct MyDouble2 : db::SimpleTag {
 };
 }  // namespace Tags
 
+struct Function {
+  using return_tags = tmpl::list<Tags::MyDouble2>;
+  using argument_tags = tmpl::list<Tags::MyDouble>;
+
+  static double apply(const gsl::not_null<double*> result, const double input) {
+    *result = input;
+    return 2.0 * input;
+  }
+
+  double operator()(const gsl::not_null<double*> result, const double input) {
+    *result = 3.0 * input;
+    return input;
+  }
+};
+
 // Test that desired tags are retrieved.
 void test_tagged_containers() {
   const auto box = db::create<db::AddSimpleTags<Tags::MyDouble>>(1.2);
@@ -63,6 +78,13 @@ void test_tagged_containers() {
   CHECK(get<Tags::MyDouble>(box, vars, tuple) == 1.2);
   CHECK(get<Tags::MyDouble2>(tuple, box, vars) == 4.4);
   CHECK(get<Tags::MyScalar>(vars, tuple, box).get() == 3.2);
+
+  CHECK(invoke(make_not_null(&tuple), Function{}, box) ==
+        get<Tags::MyDouble>(box));
+  CHECK(get<Tags::MyDouble2>(tuple) == 3.0 * get<Tags::MyDouble>(box));
+  CHECK(apply(make_not_null(&tuple), Function{}, box) ==
+        2.0 * get<Tags::MyDouble>(box));
+  CHECK(get<Tags::MyDouble2>(tuple) == get<Tags::MyDouble>(box));
 }
 }  // namespace