Improve binding.

taocpp · Oct 23, 2019 · fe0519a · fe0519a
1 parent e0944b3
commit fe0519a
Show file tree

Hide file tree

Showing 3 changed files with 11 additions and 1 deletion.
diff --git a/include/tao/json/binding/constant.hpp b/include/tao/json/binding/constant.hpp
@@ -23,6 +23,8 @@ namespace tao::json::binding
    template< bool V >
    struct element_b
    {
+      using value_t = bool;
+
       template< typename C >
       [[nodiscard]] static bool read( const C& /*unused*/ )
       {
@@ -57,6 +59,8 @@ namespace tao::json::binding
    template< std::int64_t V >
    struct element_i
    {
+      using value_t = std::int64_t;
+
       template< typename C >
       [[nodiscard]] static std::int64_t read( const C& /*unused*/ )
       {
@@ -91,6 +95,8 @@ namespace tao::json::binding
    template< std::uint64_t V >
    struct element_u
    {
+      using value_t = std::uint64_t;
+
       template< typename C >
       [[nodiscard]] static std::uint64_t read( const C& /*unused*/ )
       {
@@ -128,6 +134,8 @@ namespace tao::json::binding
    template< char... Cs >
    struct element_s< json::internal::string_t< Cs... > >
    {
+      using value_t = std::string;  // TODO: Or std::string_view? Something else? Nothing?
+
       using string = json::internal::string_t< Cs... >;
 
       template< typename C >

diff --git a/include/tao/json/binding/element.hpp b/include/tao/json/binding/element.hpp
@@ -60,6 +60,7 @@ namespace tao::json::binding
       struct element< T C::*, P, std::enable_if_t< std::is_member_function_pointer_v< T C::* > > >
       {
          using class_t = C;
+         using value_t = T;
 
          using internal_t = std::decay_t< decltype( ( std::declval< const C >().*P )() ) >;
 
@@ -79,6 +80,7 @@ namespace tao::json::binding
       struct element< T ( * )( const C& ), P >
       {
          using class_t = C;
+         using value_t = T;
 
          [[nodiscard]] static decltype( auto ) read( const C& v )
          {

diff --git a/include/tao/json/binding/internal/array.hpp b/include/tao/json/binding/internal/array.hpp
@@ -34,7 +34,7 @@ namespace tao::json::binding::internal
       }
 
       template< template< typename... > class Traits, typename C >
-      static C as_type( const basic_value< Traits >& v )  // TODO: std::enable_if_t< WHAT?, C >
+      static std::enable_if_t< std::is_constructible_v< C, typename As::value_t... >, C > as_type( const basic_value< Traits >& v )
       {
          const auto& a = get_array_impl< Traits, C >( v );
          return C( a[ Is ].template as< typename As::value_t >()... );