entity: add visit_tuple

1 files changed, 26 insertions, 1 deletions

diff --git a/src/entity.hpp b/src/entity.hpp
index 32ab759f..31a13632 100644
--- a/src/entity.hpp
+++ b/src/entity.hpp
@@ -131,11 +131,12 @@ struct Entity final {
 };
 
 namespace detail {
+
 template<typename F, typename Tuple, std::size_t N>
 requires std::invocable<F, decltype(std::get<N>(std::declval<Tuple>()))>
 constexpr CORRADE_ALWAYS_INLINE void visit_tuple(F&& fun, Tuple&& tuple)
 {
-    using Size = std::tuple_size<std::decay_t<Tuple>>;
+    using Size = std::tuple_size<std::remove_cvref_t<Tuple>>;
     static_assert(N < Size());
 
     fun(std::get<N>(tuple));
@@ -143,6 +144,20 @@ constexpr CORRADE_ALWAYS_INLINE void visit_tuple(F&& fun, Tuple&& tuple)
         visit_tuple<F, Tuple, N+1>(std::forward<F>(fun), std::forward<Tuple>(tuple));
 }
 
+template<typename F, typename Tuple, std::size_t N>
+requires std::is_invocable_r_v<bool, F, decltype(std::get<N>(std::declval<Tuple>()))>
+constexpr CORRADE_ALWAYS_INLINE bool find_in_tuple(F&& fun, Tuple&& tuple)
+{
+    using Size = std::tuple_size<std::remove_cvref_t<Tuple>>;
+    static_assert(N < Size());
+
+    if (fun(std::get<N>(tuple)))
+        return true;
+    if constexpr(N+1 < Size())
+        return find_in_tuple<F, Tuple, N+1>(std::forward<F>(fun), std::forward<Tuple>(tuple));
+    return false;
+}
+
 } // namespace detail
 
 template<typename F, typename Tuple>
@@ -153,6 +168,16 @@ constexpr void visit_tuple(F&& fun, Tuple&& tuple)
         detail::visit_tuple<F, Tuple, 0>(std::forward<F>(fun), std::forward<Tuple>(tuple));
 }
 
+template<typename F, typename Tuple>
+constexpr bool find_in_tuple(F&& fun, Tuple&& tuple)
+{
+    using Size = std::tuple_size<std::decay_t<Tuple>>;
+    if constexpr(Size() > 0)
+        return detail::find_in_tuple<F, Tuple, 0>(std::forward<F>(fun), std::forward<Tuple>(tuple));
+    else
+        return false;
+}
+
 enum class erased_field_type : std::uint32_t {
     none,
     string,