binds opts with metadata

headers/meta.hpp/meta_binds.hpp

@@ -9,9 +9,7 @@
 #include "meta_base.hpp"
 #include "meta_states.hpp"
 
-namespace meta_hpp
+namespace meta_hpp::detail
-{
-    namespace detail
 {
     template < typename Class, typename... Args >
     concept class_bind_constructor_kind =
@@ -39,12 +37,70 @@ namespace meta_hpp
         stdex::same_as<Class, typename method_traits<Method>::class_type>;
 }
 
+namespace meta_hpp
+{
+    struct class_opts final {
+        metadata_map metadata{};
+    };
+
+    struct enum_opts final {
+        metadata_map metadata{};
+    };
+
+    struct scope_opts final {
+        metadata_map metadata{};
+    };
+}
+
+namespace meta_hpp
+{
+    struct argument_opts final {
+        std::string name{};
+        metadata_map metadata{};
+    };
+
+    struct constructor_opts final {
+        std::vector<argument_opts> arguments{};
+        metadata_map metadata{};
+    };
+
+    struct destructor_opts final {
+        metadata_map metadata{};
+    };
+
+    struct evalue_opts final {
+        metadata_map metadata{};
+    };
+
+    struct function_opts final {
+        std::vector<argument_opts> arguments{};
+        metadata_map metadata{};
+    };
+
+    struct member_opts final {
+        metadata_map metadata{};
+    };
+
+    struct method_opts final {
+        std::vector<argument_opts> arguments{};
+        metadata_map metadata{};
+    };
+
+    struct variable_opts final {
+        metadata_map metadata{};
+    };
+}
+
+namespace meta_hpp
+{
     template < detail::class_kind Class >
     class class_bind final {
     public:
-        explicit class_bind();
+        explicit class_bind(class_opts opts);
         operator class_type() const noexcept;
 
+        // constructor_
+
         template < typename... Args
                  , constructor_policy_kind Policy = constructor_policy::as_object >
         class_bind& constructor_(Policy = Policy{})
@@ -52,38 +108,75 @@ namespace meta_hpp
 
         template < typename... Args
                  , constructor_policy_kind Policy = constructor_policy::as_object >
-        class_bind& constructor_(
+        class_bind& constructor_(constructor_opts opts, Policy = Policy{})
-            std::initializer_list<std::string_view> anames,
-            Policy = Policy{})
             requires detail::class_bind_constructor_kind<Class, Args...>;
 
+        // destructor_
+
         class_bind& destructor_()
             requires detail::class_bind_destructor_kind<Class>;
 
+        class_bind& destructor_(destructor_opts opts)
+            requires detail::class_bind_destructor_kind<Class>;
+
+        // base_
+
         template < detail::class_kind Base >
         class_bind& base_()
             requires detail::class_bind_base_kind<Class, Base>;
 
-        template < detail::function_kind Function
+        // function_
-                 , function_policy_kind Policy = function_policy::as_copy >
-        class_bind& function_(std::string name, Function function, Policy = Policy{});
 
         template < detail::function_kind Function
                  , function_policy_kind Policy = function_policy::as_copy >
         class_bind& function_(
             std::string name,
             Function function,
-            std::initializer_list<std::string_view> anames,
             Policy = Policy{});
 
+        template < detail::function_kind Function
+                 , function_policy_kind Policy = function_policy::as_copy >
+        class_bind& function_(
+            std::string name,
+            Function function,
+            function_opts opts,
+            Policy = Policy{});
+
+        template < detail::function_kind Function
+                 , function_policy_kind Policy = function_policy::as_copy >
+        class_bind& function_(
+            std::string name,
+            Function function,
+            std::initializer_list<std::string_view> arguments,
+            Policy = Policy{});
+
+        // member_
+
         template < detail::member_kind Member
                  , member_policy_kind Policy = member_policy::as_copy >
-        class_bind& member_(std::string name, Member member, Policy = Policy{})
+        class_bind& member_(
+            std::string name,
+            Member member,
+            Policy = Policy{})
             requires detail::class_bind_member_kind<Class, Member>;
 
+        template < detail::member_kind Member
+                 , member_policy_kind Policy = member_policy::as_copy >
+        class_bind& member_(
+            std::string name,
+            Member member,
+            member_opts opts,
+            Policy = Policy{})
+            requires detail::class_bind_member_kind<Class, Member>;
+
+        // method_
+
         template < detail::method_kind Method
                  , method_policy_kind Policy = method_policy::as_copy >
-        class_bind& method_(std::string name, Method method, Policy = Policy{})
+        class_bind& method_(
+            std::string name,
+            Method method,
+            Policy = Policy{})
             requires detail::class_bind_method_kind<Class, Method>;
 
         template < detail::method_kind Method
@@ -91,13 +184,35 @@ namespace meta_hpp
         class_bind& method_(
             std::string name,
             Method method,
-            std::initializer_list<std::string_view> anames,
+            method_opts opts,
             Policy = Policy{})
             requires detail::class_bind_method_kind<Class, Method>;
 
+        template < detail::method_kind Method
+                 , method_policy_kind Policy = method_policy::as_copy >
+        class_bind& method_(
+            std::string name,
+            Method method,
+            std::initializer_list<std::string_view> arguments,
+            Policy = Policy{})
+            requires detail::class_bind_method_kind<Class, Method>;
+
+        // variable_
+
         template < detail::pointer_kind Pointer
                  , variable_policy_kind Policy = variable_policy::as_copy >
-        class_bind& variable_(std::string name, Pointer pointer, Policy = Policy{});
+        class_bind& variable_(
+            std::string name,
+            Pointer pointer,
+            Policy = Policy{});
+
+        template < detail::pointer_kind Pointer
+                 , variable_policy_kind Policy = variable_policy::as_copy >
+        class_bind& variable_(
+            std::string name,
+            Pointer pointer,
+            variable_opts opts,
+            Policy = Policy{});
     private:
         detail::class_type_data_ptr data_;
     };
@@ -108,10 +223,11 @@ namespace meta_hpp
     template < detail::enum_kind Enum >
     class enum_bind final {
     public:
-        explicit enum_bind();
+        explicit enum_bind(enum_opts opts);
         operator enum_type() const noexcept;
 
         enum_bind& evalue_(std::string name, Enum value);
+        enum_bind& evalue_(std::string name, Enum value, evalue_opts opts);
     private:
         detail::enum_type_data_ptr data_;
     };
@@ -124,8 +240,8 @@ namespace meta_hpp
         struct local_tag {};
         struct static_tag {};
 
-        explicit scope_bind(std::string name, local_tag);
+        explicit scope_bind(std::string name, scope_opts opts, local_tag);
-        explicit scope_bind(std::string_view name, static_tag);
+        explicit scope_bind(std::string_view name, scope_opts opts, static_tag);
         operator scope() const noexcept;
 
         template < detail::class_kind Class >
@@ -134,21 +250,47 @@ namespace meta_hpp
         template < detail::enum_kind Enum >
         scope_bind& enum_(std::string name);
 
-        template < detail::function_kind Function
+        // function_
-                 , function_policy_kind Policy = function_policy::as_copy >
-        scope_bind& function_(std::string name, Function function, Policy = Policy{});
 
         template < detail::function_kind Function
                  , function_policy_kind Policy = function_policy::as_copy >
         scope_bind& function_(
             std::string name,
             Function function,
-            std::initializer_list<std::string_view> anames,
+            Policy = Policy{});
+
+        template < detail::function_kind Function
+                 , function_policy_kind Policy = function_policy::as_copy >
+        scope_bind& function_(
+            std::string name,
+            Function function,
+            function_opts opts,
+            Policy = Policy{});
+
+        template < detail::function_kind Function
+                 , function_policy_kind Policy = function_policy::as_copy >
+        scope_bind& function_(
+            std::string name,
+            Function function,
+            std::initializer_list<std::string_view> arguments,
+            Policy = Policy{});
+
+        // variable_
+
+        template < detail::pointer_kind Pointer
+                 , variable_policy_kind Policy = variable_policy::as_copy >
+        scope_bind& variable_(
+            std::string name,
+            Pointer pointer,
             Policy = Policy{});
 
         template < detail::pointer_kind Pointer
                  , variable_policy_kind Policy = variable_policy::as_copy >
-        scope_bind& variable_(std::string name, Pointer pointer, Policy = Policy{});
+        scope_bind& variable_(
+            std::string name,
+            Pointer pointer,
+            variable_opts opts,
+            Policy = Policy{});
     private:
         detail::scope_state_ptr state_;
     };
@@ -157,20 +299,20 @@ namespace meta_hpp
 namespace meta_hpp
 {
     template < detail::class_kind Class >
-    class_bind<Class> class_() {
+    class_bind<Class> class_(class_opts opts = {}) {
-        return class_bind<Class>{};
+        return class_bind<Class>{std::move(opts)};
     }
 
     template < detail::enum_kind Enum >
-    enum_bind<Enum> enum_() {
+    enum_bind<Enum> enum_(enum_opts opts = {}) {
-        return enum_bind<Enum>{};
+        return enum_bind<Enum>{std::move(opts)};
     }
 
-    inline scope_bind local_scope_(std::string name) {
+    inline scope_bind local_scope_(std::string name, scope_opts opts = {}) {
-        return scope_bind{std::move(name), scope_bind::local_tag()};
+        return scope_bind{std::move(name), std::move(opts), scope_bind::local_tag()};
     }
 
-    inline scope_bind static_scope_(std::string_view name) {
+    inline scope_bind static_scope_(std::string_view name, scope_opts opts = {}) {
-        return scope_bind{name, scope_bind::static_tag()};
+        return scope_bind{name, std::move(opts), scope_bind::static_tag()};
     }
 }

headers/meta.hpp/meta_binds/class_bind.hpp

@@ -14,14 +14,21 @@
 namespace meta_hpp
 {
     template < detail::class_kind Class >
-    class_bind<Class>::class_bind()
+    class_bind<Class>::class_bind(class_opts opts)
-    : data_{detail::type_access(detail::resolve_type<Class>())} {}
+    : data_{detail::type_access(detail::resolve_type<Class>())} {
+        data_->metadata.swap(opts.metadata);
+        data_->metadata.merge(opts.metadata);
+    }
 
     template < detail::class_kind Class >
     class_bind<Class>::operator class_type() const noexcept {
         return class_type{data_};
     }
 
+    //
+    // constructor_
+    //
+
     template < detail::class_kind Class >
     template < typename... Args, constructor_policy_kind Policy >
     class_bind<Class>& class_bind<Class>::constructor_(Policy policy)
@@ -33,34 +40,50 @@ namespace meta_hpp
     template < detail::class_kind Class >
     template < typename... Args, constructor_policy_kind Policy >
     class_bind<Class>& class_bind<Class>::constructor_(
-        std::initializer_list<std::string_view> anames,
+        constructor_opts opts,
         [[maybe_unused]] Policy policy)
         requires detail::class_bind_constructor_kind<Class, Args...>
     {
-        auto constructor_state = detail::constructor_state::make<Policy, Class, Args...>();
+        auto state = detail::constructor_state::make<Policy, Class, Args...>(std::move(opts.metadata));
 
-        if ( anames.size() > constructor_state->arguments.size() ) {
+        if ( opts.arguments.size() > state->arguments.size() ) {
             detail::throw_exception_with("provided argument names don't match constructor argument count");
         }
 
-        for ( std::size_t i = 0; i < anames.size(); ++i ) {
+        for ( std::size_t i = 0; i < opts.arguments.size(); ++i ) {
-            argument& arg = constructor_state->arguments[i];
+            argument& arg = state->arguments[i];
-            detail::state_access(arg)->name = std::string{std::data(anames)[i]};
+            detail::state_access(arg)->name = std::move(opts.arguments[i].name);
+            detail::state_access(arg)->metadata = std::move(opts.arguments[i].metadata);
         }
 
-        data_->constructors.emplace(constructor_state->index, std::move(constructor_state));
+        data_->constructors.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 
+    //
+    // destructor_
+    //
+
     template < detail::class_kind Class >
     class_bind<Class>& class_bind<Class>::destructor_()
         requires detail::class_bind_destructor_kind<Class>
     {
-        auto destructor_state = detail::destructor_state::make<Class>();
+        return destructor_({});
-        data_->destructors.emplace(destructor_state->index, std::move(destructor_state));
+    }
+
+    template < detail::class_kind Class >
+    class_bind<Class>& class_bind<Class>::destructor_(destructor_opts opts)
+        requires detail::class_bind_destructor_kind<Class>
+    {
+        auto state = detail::destructor_state::make<Class>(std::move(opts.metadata));
+        data_->destructors.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 
+    //
+    // base_
+    //
+
     template < detail::class_kind Class >
     template < detail::class_kind Base >
     class_bind<Class>& class_bind<Class>::base_()
@@ -75,9 +98,17 @@ namespace meta_hpp
         return *this;
     }
 
+    //
+    // function_
+    //
+
     template < detail::class_kind Class >
     template < detail::function_kind Function, function_policy_kind Policy >
-    class_bind<Class>& class_bind<Class>::function_(std::string name, Function function, Policy policy) {
+    class_bind<Class>& class_bind<Class>::function_(
+        std::string name,
+        Function function,
+        Policy policy)
+    {
         return function_(std::move(name), std::move(function), {}, policy);
     }
 
@@ -86,37 +117,96 @@ namespace meta_hpp
     class_bind<Class>& class_bind<Class>::function_(
         std::string name,
         Function function,
-        std::initializer_list<std::string_view> anames,
+        function_opts opts,
         [[maybe_unused]] Policy policy)
     {
-        auto function_state = detail::function_state::make<Policy>(std::move(name), std::move(function));
+        auto state = detail::function_state::make<Policy>(
+            std::move(name),
+            std::move(function),
+            std::move(opts.metadata));
 
-        if ( anames.size() > function_state->arguments.size() ) {
+        if ( opts.arguments.size() > state->arguments.size() ) {
+            detail::throw_exception_with("provided arguments don't match function argument count");
+        }
+
+        for ( std::size_t i = 0; i < opts.arguments.size(); ++i ) {
+            argument& arg = state->arguments[i];
+            detail::state_access(arg)->name = std::move(opts.arguments[i].name);
+            detail::state_access(arg)->metadata = std::move(opts.arguments[i].metadata);
+        }
+
+        data_->functions.insert_or_assign(state->index, std::move(state));
+        return *this;
+    }
+
+    template < detail::class_kind Class >
+    template < detail::function_kind Function, function_policy_kind Policy >
+    class_bind<Class>& class_bind<Class>::function_(
+        std::string name,
+        Function function,
+        std::initializer_list<std::string_view> arguments,
+        [[maybe_unused]] Policy policy)
+    {
+        auto state = detail::function_state::make<Policy>(
+            std::move(name),
+            std::move(function),
+            {});
+
+        if ( arguments.size() > state->arguments.size() ) {
             detail::throw_exception_with("provided argument names don't match function argument count");
         }
 
-        for ( std::size_t i = 0; i < anames.size(); ++i ) {
+        for ( std::size_t i = 0; i < arguments.size(); ++i ) {
-            argument& arg = function_state->arguments[i];
+            argument& arg = state->arguments[i];
-            detail::state_access(arg)->name = std::string{std::data(anames)[i]};
+            detail::state_access(arg)->name = std::data(arguments)[i];
         }
 
-        data_->functions.emplace(function_state->index, std::move(function_state));
+        data_->functions.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 
+    //
+    // member_
+    //
+
+    template < detail::class_kind Class >
+    template < detail::member_kind Member, member_policy_kind Policy >
+    class_bind<Class>& class_bind<Class>::member_(
+        std::string name,
+        Member member,
+        Policy policy)
+        requires detail::class_bind_member_kind<Class, Member>
+    {
+        return member_(std::move(name), std::move(member), {}, policy);
+    }
+
     template < detail::class_kind Class >
     template < detail::member_kind Member, member_policy_kind Policy >
-    class_bind<Class>& class_bind<Class>::member_(std::string name, Member member, [[maybe_unused]] Policy policy)
+    class_bind<Class>& class_bind<Class>::member_(
+        std::string name,
+        Member member,
+        member_opts opts,
+        [[maybe_unused]] Policy policy)
         requires detail::class_bind_member_kind<Class, Member>
     {
-        auto member_state = detail::member_state::make<Policy>(std::move(name), std::move(member));
+        auto state = detail::member_state::make<Policy>(
-        data_->members.emplace(member_state->index, std::move(member_state));
+            std::move(name),
+            std::move(member),
+            std::move(opts.metadata));
+        data_->members.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 
+    //
+    // method_
+    //
+
     template < detail::class_kind Class >
     template < detail::method_kind Method, method_policy_kind Policy >
-    class_bind<Class>& class_bind<Class>::method_(std::string name, Method method, Policy policy)
+    class_bind<Class>& class_bind<Class>::method_(
+        std::string name,
+        Method method,
+        Policy policy)
         requires detail::class_bind_method_kind<Class, Method>
     {
         return method_(std::move(name), std::move(method), {}, policy);
@@ -127,30 +217,83 @@ namespace meta_hpp
     class_bind<Class>& class_bind<Class>::method_(
         std::string name,
         Method method,
-        std::initializer_list<std::string_view> anames,
+        method_opts opts,
         [[maybe_unused]] Policy policy)
         requires detail::class_bind_method_kind<Class, Method>
     {
-        auto method_state = detail::method_state::make<Policy>(std::move(name), std::move(method));
+        auto state = detail::method_state::make<Policy>(
+            std::move(name),
+            std::move(method),
+            std::move(opts.metadata));
 
-        if ( anames.size() > method_state->arguments.size() ) {
+        if ( opts.arguments.size() > state->arguments.size() ) {
-            detail::throw_exception_with("provided argument names don't match method argument count");
+            detail::throw_exception_with("provided arguments don't match method argument count");
         }
 
-        for ( std::size_t i = 0; i < anames.size(); ++i ) {
+        for ( std::size_t i = 0; i < opts.arguments.size(); ++i ) {
-            argument& arg = method_state->arguments[i];
+            argument& arg = state->arguments[i];
-            detail::state_access(arg)->name = std::string{std::data(anames)[i]};
+            detail::state_access(arg)->name = std::move(opts.arguments[i].name);
+            detail::state_access(arg)->metadata = std::move(opts.arguments[i].metadata);
         }
 
-        data_->methods.emplace(method_state->index, std::move(method_state));
+        data_->methods.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 
+    template < detail::class_kind Class >
+    template < detail::method_kind Method, method_policy_kind Policy >
+    class_bind<Class>& class_bind<Class>::method_(
+        std::string name,
+        Method method,
+        std::initializer_list<std::string_view> arguments,
+        [[maybe_unused]] Policy policy)
+        requires detail::class_bind_method_kind<Class, Method>
+    {
+        auto state = detail::method_state::make<Policy>(
+            std::move(name),
+            std::move(method),
+            {});
+
+        if ( arguments.size() > state->arguments.size() ) {
+            detail::throw_exception_with("provided argument names don't match method argument count");
+        }
+
+        for ( std::size_t i = 0; i < arguments.size(); ++i ) {
+            argument& arg = state->arguments[i];
+            detail::state_access(arg)->name = std::data(arguments)[i];
+        }
+
+        data_->methods.insert_or_assign(state->index, std::move(state));
+        return *this;
+    }
+
+    //
+    // variable_
+    //
+
     template < detail::class_kind Class >
     template < detail::pointer_kind Pointer, variable_policy_kind Policy >
-    class_bind<Class>& class_bind<Class>::variable_( std::string name, Pointer pointer, [[maybe_unused]] Policy policy) {
+    class_bind<Class>& class_bind<Class>::variable_(
-        auto variable_state = detail::variable_state::make<Policy>(std::move(name), std::move(pointer));
+        std::string name,
-        data_->variables.emplace(variable_state->index, std::move(variable_state));
+        Pointer pointer,
+        Policy policy)
+    {
+        return variable_(std::move(name), std::move(pointer), {}, policy);
+    }
+
+    template < detail::class_kind Class >
+    template < detail::pointer_kind Pointer, variable_policy_kind Policy >
+    class_bind<Class>& class_bind<Class>::variable_(
+        std::string name,
+        Pointer pointer,
+        variable_opts opts,
+        [[maybe_unused]] Policy policy)
+    {
+        auto state = detail::variable_state::make<Policy>(
+            std::move(name),
+            std::move(pointer),
+            std::move(opts.metadata));
+        data_->variables.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 }

headers/meta.hpp/meta_binds/enum_bind.hpp

@@ -14,8 +14,11 @@
 namespace meta_hpp
 {
     template < detail::enum_kind Enum >
-    enum_bind<Enum>::enum_bind()
+    enum_bind<Enum>::enum_bind(enum_opts opts)
-    : data_{detail::type_access(detail::resolve_type<Enum>())} {}
+    : data_{detail::type_access(detail::resolve_type<Enum>())} {
+        data_->metadata.swap(opts.metadata);
+        data_->metadata.merge(opts.metadata);
+    }
 
     template < detail::enum_kind Enum >
     enum_bind<Enum>::operator enum_type() const noexcept {
@@ -24,8 +27,16 @@ namespace meta_hpp
 
     template < detail::enum_kind Enum >
     enum_bind<Enum>& enum_bind<Enum>::evalue_(std::string name, Enum value) {
-        auto evalue_state = detail::evalue_state::make(std::move(name), std::move(value));
+        return evalue_(std::move(name), std::move(value), {});
-        data_->evalues.emplace(evalue_state->index, std::move(evalue_state));
+    }
+
+    template < detail::enum_kind Enum >
+    enum_bind<Enum>& enum_bind<Enum>::evalue_(std::string name, Enum value, evalue_opts opts) {
+        auto state = detail::evalue_state::make(
+            std::move(name),
+            std::move(value),
+            std::move(opts.metadata));
+        data_->evalues.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 }

headers/meta.hpp/meta_binds/scope_bind.hpp

@@ -15,12 +15,15 @@
 namespace meta_hpp
 {
     // NOLINTNEXTLINE(readability-named-parameter)
-    inline scope_bind::scope_bind(std::string name, local_tag)
+    inline scope_bind::scope_bind(std::string name, scope_opts opts, local_tag)
-    : state_{detail::scope_state::make(std::move(name))} {}
+    : state_{detail::scope_state::make(std::move(name), std::move(opts.metadata))} {}
 
     // NOLINTNEXTLINE(readability-named-parameter)
-    inline scope_bind::scope_bind(std::string_view name, static_tag)
+    inline scope_bind::scope_bind(std::string_view name, scope_opts opts, static_tag)
-    : state_{detail::state_access(detail::resolve_scope(name))} {}
+    : state_{detail::state_access(detail::resolve_scope(name))} {
+        state_->metadata.swap(opts.metadata);
+        state_->metadata.merge(opts.metadata);
+    }
 
     inline scope_bind::operator scope() const noexcept {
         return scope{state_};
@@ -38,8 +41,16 @@ namespace meta_hpp
         return *this;
     }
 
+    //
+    // function_
+    //
+
     template < detail::function_kind Function, function_policy_kind Policy >
-    scope_bind& scope_bind::function_(std::string name, Function function, Policy policy) {
+    scope_bind& scope_bind::function_(
+        std::string name,
+        Function function,
+        Policy policy)
+    {
         return function_(std::move(name), std::move(function), {}, policy);
     }
 
@@ -47,28 +58,78 @@ namespace meta_hpp
     scope_bind& scope_bind::function_(
         std::string name,
         Function function,
-        std::initializer_list<std::string_view> anames,
+        function_opts opts,
         [[maybe_unused]] Policy policy)
     {
-        auto function_state = detail::function_state::make<Policy>(std::move(name), std::move(function));
+        auto state = detail::function_state::make<Policy>(
+            std::move(name),
+            std::move(function),
+            std::move(opts.metadata));
 
-        if ( anames.size() > function_state->arguments.size() ) {
+        if ( opts.arguments.size() > state->arguments.size() ) {
+            detail::throw_exception_with("provided arguments don't match function argument count");
+        }
+
+        for ( std::size_t i = 0; i < opts.arguments.size(); ++i ) {
+            argument& arg = state->arguments[i];
+            detail::state_access(arg)->name = std::move(opts.arguments[i].name);
+            detail::state_access(arg)->metadata = std::move(opts.arguments[i].metadata);
+        }
+
+        state_->functions.insert_or_assign(state->index, std::move(state));
+        return *this;
+    }
+
+    template < detail::function_kind Function, function_policy_kind Policy >
+    scope_bind& scope_bind::function_(
+        std::string name,
+        Function function,
+        std::initializer_list<std::string_view> arguments,
+        [[maybe_unused]] Policy policy)
+    {
+        auto state = detail::function_state::make<Policy>(
+            std::move(name),
+            std::move(function),
+            {});
+
+        if ( arguments.size() > state->arguments.size() ) {
             detail::throw_exception_with("provided argument names don't match function argument count");
         }
 
-        for ( std::size_t i = 0; i < anames.size(); ++i ) {
+        for ( std::size_t i = 0; i < arguments.size(); ++i ) {
-            argument& arg = function_state->arguments[i];
+            argument& arg = state->arguments[i];
-            detail::state_access(arg)->name = std::string{std::data(anames)[i]};
+            detail::state_access(arg)->name = std::data(arguments)[i];
         }
 
-        state_->functions.emplace(function_state->index, std::move(function_state));
+        state_->functions.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 
+    //
+    // variable_
+    //
+
+    template < detail::pointer_kind Pointer, variable_policy_kind Policy >
+    scope_bind& scope_bind::variable_(
+        std::string name,
+        Pointer pointer,
+        Policy policy)
+    {
+        return variable_(std::move(name), std::move(pointer), {}, policy);
+    }
+
     template < detail::pointer_kind Pointer, variable_policy_kind Policy >
-    scope_bind& scope_bind::variable_(std::string name, Pointer pointer, [[maybe_unused]] Policy policy) {
+    scope_bind& scope_bind::variable_(
-        auto variable_state = detail::variable_state::make<Policy>(std::move(name), std::move(pointer));
+        std::string name,
-        state_->variables.emplace(variable_state->index, std::move(variable_state));
+        Pointer pointer,
+        variable_opts opts,
+        [[maybe_unused]] Policy policy)
+    {
+        auto state = detail::variable_state::make<Policy>(
+            std::move(name),
+            std::move(pointer),
+            std::move(opts.metadata));
+        state_->variables.insert_or_assign(state->index, std::move(state));
         return *this;
     }
 }

untests/meta_states/metadata_tests.cpp

@@ -0,0 +1,246 @@
+/*******************************************************************************
+ * This file is part of the "https://github.com/blackmatov/meta.hpp"
+ * For conditions of distribution and use, see copyright notice in LICENSE.md
+ * Copyright (C) 2021-2022, by Matvey Cherevko (blackmatov@gmail.com)
+ ******************************************************************************/
+
+#include "../meta_untests.hpp"
+
+namespace
+{
+    enum class color : unsigned {
+        red = 0xFF0000,
+        green = 0x00FF00,
+        blue = 0x0000FF,
+    };
+
+    struct ivec2 {
+        int x{};
+        int y{};
+
+        explicit ivec2(int v) : x{v}, y{v} {}
+        ivec2(int x, int y) : x{x}, y{y} {}
+
+        ivec2& add(const ivec2& other) noexcept {
+            x += other.x;
+            y += other.y;
+            return *this;
+        }
+
+        static ivec2 iadd(const ivec2& l, const ivec2& r) noexcept {
+            return {l.x + r.x, l.y + r.y};
+        }
+    };
+}
+
+TEST_CASE("meta/meta_states/metadata/enum") {
+    namespace meta = meta_hpp;
+    using namespace std::string_literals;
+
+    meta::enum_<color>({
+        .metadata{
+            {"desc1", meta::uvalue{"enum-desc1"s}},
+            {"desc2", meta::uvalue{"enum-desc2"s}},
+        }
+    })
+    .evalue_("red", color::red, {
+        .metadata{{"desc1", meta::uvalue{"red-color"s}}}
+    })
+    .evalue_("green", color::green, {
+        .metadata{{"desc1", meta::uvalue{"green-color"s}}}
+    })
+    .evalue_("blue", color::blue, {
+        .metadata{{"desc1", meta::uvalue{"blue-color"s}}}
+    });
+
+    // metadata override
+
+    meta::enum_<color>({
+        .metadata{
+            {"desc2", meta::uvalue{"new-enum-desc2"s}},
+            {"desc3", meta::uvalue{"new-enum-desc3"s}},
+        }
+    });
+
+    meta::enum_<color>()
+        .evalue_("red", color::red, {
+            .metadata{
+                {"desc2", meta::uvalue{"new-red-color"s}},
+            }
+        });
+
+    //
+
+    const meta::enum_type color_type = meta::resolve_type<color>();
+    REQUIRE(color_type);
+
+    SUBCASE("color") {
+        CHECK(color_type.get_metadata().at("desc1") == "enum-desc1"s);
+        CHECK(color_type.get_metadata().at("desc2") == "new-enum-desc2"s);
+        CHECK(color_type.get_metadata().at("desc3") == "new-enum-desc3"s);
+    }
+
+    SUBCASE("color::red") {
+        const meta::evalue red_evalue = color_type.get_evalue("red");
+        REQUIRE(red_evalue);
+        CHECK_FALSE(red_evalue.get_metadata().contains("desc1"));
+        CHECK(red_evalue.get_metadata().at("desc2") == "new-red-color"s);
+    }
+}
+
+TEST_CASE("meta/meta_states/metadata/class") {
+    namespace meta = meta_hpp;
+    using namespace std::string_literals;
+
+    meta::class_<ivec2>({
+        .metadata{
+            {"desc1", meta::uvalue{"class-desc1"s}},
+            {"desc2", meta::uvalue{"class-desc2"s}},
+        },
+    })
+    .constructor_<int>({
+        .arguments{{
+            .name{"v"},
+            .metadata{{"desc", meta::uvalue{"the ctor arg"s}}},
+        }},
+        .metadata{{"desc", meta::uvalue{"one arg 2d vector ctor"s}}},
+    })
+    .constructor_<int, int>({
+        .arguments{{
+            .name{"x"},
+            .metadata{{"desc", meta::uvalue{"the 1st ctor arg"s}}},
+        },{
+            .name{"y"},
+            .metadata{{"desc", meta::uvalue{"the 2nd ctor arg"s}}},
+        }},
+        .metadata{{"desc", meta::uvalue{"two args 2d vector ctor"s}}}
+    })
+    .member_("x", &ivec2::x, {
+        .metadata{{"desc", meta::uvalue{"x-member"s}}}
+    })
+    .member_("y", &ivec2::y, {
+        .metadata{{"desc", meta::uvalue{"y-member"s}}}
+    })
+    .method_("add", &ivec2::add, {
+        .arguments{{
+            .name{"other"},
+            .metadata{{"desc", meta::uvalue{"other-arg"s}}}
+        }},
+        .metadata{{"desc", meta::uvalue{"add-method"s}}}
+    })
+    .function_("iadd", &ivec2::iadd, {
+        .arguments{{
+            .name{"l"},
+            .metadata{{"desc", meta::uvalue{"l-arg"s}}}
+        },{
+            .name{"r"},
+            .metadata{{"desc", meta::uvalue{"r-arg"s}}}
+        }},
+        .metadata{{"desc", meta::uvalue{"iadd-function"s}}}
+    });
+
+    // metadata override
+
+    meta::class_<ivec2>({
+        .metadata{
+            {"desc2", meta::uvalue{"new-class-desc2"s}},
+            {"desc3", meta::uvalue{"new-class-desc3"s}},
+        }
+    });
+
+    //
+
+    const meta::class_type ivec2_type = meta::resolve_type<ivec2>();
+    REQUIRE(ivec2_type);
+
+    SUBCASE("ivec2") {
+        CHECK(ivec2_type.get_metadata().at("desc1") == "class-desc1"s);
+        CHECK(ivec2_type.get_metadata().at("desc2") == "new-class-desc2"s);
+        CHECK(ivec2_type.get_metadata().at("desc3") == "new-class-desc3"s);
+    }
+
+    SUBCASE("ivec2(int)") {
+        const meta::constructor ivec2_ctor = ivec2_type.get_constructor_with<int>();
+        REQUIRE(ivec2_ctor);
+
+        REQUIRE(ivec2_ctor.get_metadata().contains("desc"));
+        CHECK(ivec2_ctor.get_metadata().at("desc") == "one arg 2d vector ctor"s);
+
+        REQUIRE(ivec2_ctor.get_argument(0));
+        CHECK(ivec2_ctor.get_argument(0).get_name() == "v");
+        CHECK(ivec2_ctor.get_argument(0).get_position() == 0);
+        CHECK(ivec2_ctor.get_argument(0).get_type() == meta::resolve_type<int>());
+        REQUIRE(ivec2_ctor.get_argument(0).get_metadata().contains("desc"));
+        CHECK(ivec2_ctor.get_argument(0).get_metadata().at("desc") == "the ctor arg"s);
+
+        REQUIRE_FALSE(ivec2_ctor.get_argument(1));
+    }
+
+    SUBCASE("ivec2(int, int)") {
+        const meta::constructor ivec2_ctor = ivec2_type.get_constructor_with<int, int>();
+        REQUIRE(ivec2_ctor);
+
+        REQUIRE(ivec2_ctor.get_metadata().contains("desc"));
+        CHECK(ivec2_ctor.get_metadata().at("desc") == "two args 2d vector ctor"s);
+
+        REQUIRE(ivec2_ctor.get_argument(0));
+        CHECK(ivec2_ctor.get_argument(0).get_name() == "x");
+        CHECK(ivec2_ctor.get_argument(0).get_position() == 0);
+        CHECK(ivec2_ctor.get_argument(0).get_type() == meta::resolve_type<int>());
+        REQUIRE(ivec2_ctor.get_argument(0).get_metadata().contains("desc"));
+        CHECK(ivec2_ctor.get_argument(0).get_metadata().at("desc") == "the 1st ctor arg"s);
+
+        REQUIRE(ivec2_ctor.get_argument(1));
+        CHECK(ivec2_ctor.get_argument(1).get_name() == "y");
+        CHECK(ivec2_ctor.get_argument(1).get_position() == 1);
+        CHECK(ivec2_ctor.get_argument(1).get_type() == meta::resolve_type<int>());
+        REQUIRE(ivec2_ctor.get_argument(1).get_metadata().contains("desc"));
+        CHECK(ivec2_ctor.get_argument(1).get_metadata().at("desc") == "the 2nd ctor arg"s);
+
+        REQUIRE_FALSE(ivec2_ctor.get_argument(2));
+    }
+
+    SUBCASE("ivec2::x") {
+        const meta::member ivec2_x = ivec2_type.get_member("x");
+        REQUIRE(ivec2_x);
+
+        REQUIRE(ivec2_x.get_metadata().contains("desc"));
+        CHECK(ivec2_x.get_metadata().at("desc") == "x-member"s);
+    }
+
+    SUBCASE("ivec2::y") {
+        const meta::member ivec2_y = ivec2_type.get_member("y");
+        REQUIRE(ivec2_y);
+
+        REQUIRE(ivec2_y.get_metadata().contains("desc"));
+        CHECK(ivec2_y.get_metadata().at("desc") == "y-member"s);
+    }
+
+    SUBCASE("ivec2::add") {
+        const meta::method ivec2_add = ivec2_type.get_method("add");
+        REQUIRE(ivec2_add);
+
+        REQUIRE(ivec2_add.get_metadata().contains("desc"));
+        CHECK(ivec2_add.get_metadata().at("desc") == "add-method"s);
+
+        REQUIRE(ivec2_add.get_argument(0));
+        REQUIRE(ivec2_add.get_argument(0).get_metadata().contains("desc"));
+        CHECK(ivec2_add.get_argument(0).get_metadata().at("desc") == "other-arg"s);
+    }
+
+    SUBCASE("ivec2::iadd") {
+        const meta::function ivec2_iadd = ivec2_type.get_function("iadd");
+        REQUIRE(ivec2_iadd);
+
+        REQUIRE(ivec2_iadd.get_metadata().contains("desc"));
+        CHECK(ivec2_iadd.get_metadata().at("desc") == "iadd-function"s);
+
+        REQUIRE(ivec2_iadd.get_argument(0));
+        REQUIRE(ivec2_iadd.get_argument(0).get_metadata().contains("desc"));
+        CHECK(ivec2_iadd.get_argument(0).get_metadata().at("desc") == "l-arg"s);
+
+        REQUIRE(ivec2_iadd.get_argument(1));
+        REQUIRE(ivec2_iadd.get_argument(1).get_metadata().contains("desc"));
+        CHECK(ivec2_iadd.get_argument(1).get_metadata().at("desc") == "r-arg"s);
+    }
+}

untests/meta_utilities/arg_tests.cpp

@@ -70,7 +70,7 @@ namespace
     {\
         using namespace meta::detail;\
         auto function_ptr = meta::select_overload<int(ToType)>(&FName);\
-        meta::function f_state{function_state::make<meta::function_policy::as_copy>("", function_ptr)};\
+        meta::function f_state{function_state::make<meta::function_policy::as_copy>("", function_ptr, {})};\
         \
         if ( std::is_invocable_v<decltype(function_ptr), decltype(FromValue)> ) {\
             CHECK(uarg{FromValue}.can_cast_to<ToType>());\
@@ -94,7 +94,7 @@ namespace
     {\
         using namespace meta::detail;\
         auto function_ptr = meta::select_overload<int(ToType)>(&FName);\
-        meta::function f_state{function_state::make<meta::function_policy::as_copy>("", function_ptr)};\
+        meta::function f_state{function_state::make<meta::function_policy::as_copy>("", function_ptr, {})};\
         \
         if ( std::is_invocable_v<decltype(function_ptr), FromType> ) {\
             CHECK(f_state.is_invocable_with<FromType>());\

untests/meta_utilities/inst_tests.cpp

@@ -30,7 +30,7 @@ namespace
     {\
         using namespace meta::detail;\
         auto method_ptr = meta::select_overload<int() Qualifiers>(&clazz::FName);\
-        meta::method m_state{method_state::make<meta::method_policy::as_copy>("", method_ptr)};\
+        meta::method m_state{method_state::make<meta::method_policy::as_copy>("", method_ptr, {})};\
         \
         if ( std::is_invocable_v<decltype(method_ptr), decltype(Inst)> ) {\
             CHECK(uinst{Inst}.can_cast_to<clazz Qualifiers>());\
@@ -54,7 +54,7 @@ namespace
     {\
         using namespace meta::detail;\
         auto method_ptr = meta::select_overload<int() ToQualifiers>(&clazz::FName);\
-        meta::method m_state{method_state::make<meta::method_policy::as_copy>("", method_ptr)};\
+        meta::method m_state{method_state::make<meta::method_policy::as_copy>("", method_ptr, {})};\
         \
         if ( std::is_invocable_v<decltype(method_ptr), FromType> ) {\
             CHECK(m_state.is_invocable_with<FromType>());\