add value helper-functions

headers/meta.hpp/meta_fwd.hpp

@@ -8,6 +8,8 @@
 
 #include <any>
 #include <array>
+#include <cstddef>
+#include <cstdint>
 #include <functional>
 #include <map>
 #include <optional>

headers/meta.hpp/meta_value.hpp

@@ -18,6 +18,10 @@ namespace meta_hpp
         value(T&& value)
         : raw_{std::forward<T>(value)} {}
 
+        template < typename T, typename... Args >
+        value(std::in_place_type_t<T>, Args&&... args)
+        : raw_{std::in_place_type<T>, std::forward<Args>(args)...} {}
+
         template < typename T >
         auto cast() const {
             return std::any_cast<T>(raw_);
@@ -32,6 +36,25 @@ namespace meta_hpp
         auto try_cast() const noexcept {
             return std::any_cast<T>(&raw_);
         }
+    public:
+        bool to_bool() const { return cast<bool>(); }
+        int to_int() const { return cast<int>(); }
+        float to_float() const { return cast<float>(); }
+        double to_double() const { return cast<double>(); }
+        std::string to_string() const { return cast<std::string>(); }
+
+        std::int8_t to_int8() const { return cast<std::int8_t>(); }
+        std::int16_t to_int16() const { return cast<std::int16_t>(); }
+        std::int32_t to_int32() const { return cast<std::int32_t>(); }
+        std::int64_t to_int64() const { return cast<std::int64_t>(); }
+
+        std::uint8_t to_uint8() const { return cast<std::uint8_t>(); }
+        std::uint16_t to_uint16() const { return cast<std::uint16_t>(); }
+        std::uint32_t to_uint32() const { return cast<std::uint32_t>(); }
+        std::uint64_t to_uint64() const { return cast<std::uint64_t>(); }
+
+        std::size_t to_size_t() const { return cast<std::size_t>(); }
+        std::ptrdiff_t to_ptrdiff_t() const { return cast<std::ptrdiff_t>(); }
     private:
         std::any raw_;
     };

untests/meta_value_tests.cpp

@@ -13,4 +13,24 @@ namespace
 
 TEST_CASE("meta/value") {
     namespace meta = meta_hpp;
+    using namespace std::string_literals;
+
+    CHECK(meta::value{true}.to_bool() == true);
+    CHECK(meta::value{1}.to_int() == 1);
+    CHECK(meta::value{1.f}.to_float() == 1.f);
+    CHECK(meta::value{1.0}.to_double() == 1.0);
+    CHECK(meta::value{"meta"s}.to_string() == "meta");
+
+    CHECK(meta::value{std::in_place_type<std::int8_t>, 1}.to_int8() == 1);
+    CHECK(meta::value{std::in_place_type<std::int16_t>, 1}.to_int16() == 1);
+    CHECK(meta::value{std::in_place_type<std::int32_t>, 1}.to_int32() == 1);
+    CHECK(meta::value{std::in_place_type<std::int64_t>, 1}.to_int64() == 1);
+
+    CHECK(meta::value{std::in_place_type<std::uint8_t>, 1}.to_uint8() == 1u);
+    CHECK(meta::value{std::in_place_type<std::uint16_t>, 1}.to_uint16() == 1u);
+    CHECK(meta::value{std::in_place_type<std::uint32_t>, 1}.to_uint32() == 1u);
+    CHECK(meta::value{std::in_place_type<std::uint64_t>, 1}.to_uint64() == 1u);
+
+    CHECK(meta::value{std::in_place_type<std::size_t>, 1}.to_size_t() == 1u);
+    CHECK(meta::value{std::in_place_type<std::ptrdiff_t>, 1}.to_ptrdiff_t() == 1u);
 }