From d94d56bb395f64a819c72fe5d09228ec31e0dd93 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Sat, 19 Nov 2022 13:34:39 +0100
Subject: entity: wip constraints

---
 entity/constraints.hpp |  2 +-
 entity/metadata.hpp    | 23 ++++++++++++++++-------
 2 files changed, 17 insertions(+), 8 deletions(-)

(limited to 'entity')

diff --git a/entity/constraints.hpp b/entity/constraints.hpp
index f629b149..f8434bd7 100644
--- a/entity/constraints.hpp
+++ b/entity/constraints.hpp
@@ -50,7 +50,7 @@ template<typename T> constexpr std::pair<T, T> range::convert() const
 }
 
 struct length final {
-    std::size_t value = (std::size_t)-1;
+    std::size_t value = std::numeric_limits<std::size_t>::max();
 };
 
 struct group final {
diff --git a/entity/metadata.hpp b/entity/metadata.hpp
index a402a2a3..8bd36cb8 100644
--- a/entity/metadata.hpp
+++ b/entity/metadata.hpp
@@ -65,6 +65,9 @@ template<typename Obj, typename Type, typename Default, std::size_t I, typename
 requires FieldReader<F, Obj, Type>
 struct find_reader<Obj, Type, Default, I, F, Fs...> { using type = F; static constexpr std::size_t index = I; };
 
+template<typename Obj, typename Type, typename... Fs>
+using find_reader2 = find_reader<Obj, Type, Type, 0, Fs...>;
+
 template<typename Obj, auto constant>
 constexpr auto constantly = [](const Obj&) constexpr { return constant; };
 
@@ -80,9 +83,9 @@ private:
     static constexpr auto default_predicate = detail::constantly<Obj, field_status::enabled>;
     using default_predicate_t = std::decay_t<decltype(default_predicate)>;
     using c_predicate = detail::find_reader<Obj, field_status, default_predicate_t, 0, Ts...>;
-    using c_range  = detail::find_reader<Obj, constraints::range<Type>, constraints::range<Type>, 0, Ts...>;
-    using c_length = detail::find_reader<Obj, constraints::length, constraints::length, 0, Ts...>;
-    using c_group  = detail::find_reader<Obj, constraints::group, constraints::group, 0, Ts...>;
+    using c_range  = detail::find_reader2<Obj, constraints::range<Type>, Ts...>;
+    using c_length = detail::find_reader2<Obj, constraints::length, Ts...>;
+    using c_group  = detail::find_reader2<Obj, constraints::group, Ts...>;
     static constexpr std::size_t good_arguments =
         unsigned(c_predicate::index != sizeof...(Ts)) +
         unsigned(c_range::index != sizeof...(Ts)) +
@@ -96,14 +99,17 @@ public:
     using Reader = R;
     using Writer = W;
     using Predicate = typename c_predicate::type;
+    using Range = typename c_range::type;
+    using Length = typename c_length::type;
+    using Group = typename c_group::type;
 
     StringView name;
     [[no_unique_address]] R reader;
     [[no_unique_address]] W writer;
     [[no_unique_address]] Predicate predicate;
-    [[no_unique_address]] c_range range;
-    [[no_unique_address]] c_length length;
-    [[no_unique_address]] c_group group;
+    [[no_unique_address]] Range range;
+    [[no_unique_address]] Length length;
+    [[no_unique_address]] Group group;
 
     constexpr entity_field(const entity_field&) = default;
     constexpr entity_field& operator=(const entity_field&) = default;
@@ -115,7 +121,10 @@ public:
     static constexpr field_status is_enabled(const Predicate & p, const Obj& x);
     constexpr entity_field(StringView name, R r, W w, Ts&&... ts) noexcept :
         name{name}, reader{r}, writer{w},
-        predicate{std::get<c_predicate::index>(std::forward_as_tuple(ts..., default_predicate))}
+        predicate{std::get<c_predicate::index>(std::forward_as_tuple(ts..., default_predicate))},
+        range{std::get<c_range::index>(std::forward_as_tuple(ts..., constraints::range<Type>{}))},
+        length{std::get<c_length::index>(std::forward_as_tuple(ts..., constraints::length{}))},
+        group{std::get<c_length::index>(std::forward_as_tuple(ts..., constraints::group{}))}
     {}
     constexpr erased_accessor erased() const;
 };
-- 
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