[keel] Add cleaner way to write type converters

src/olympic/keel/include/keel/typeconv.hpp

@@ -174,6 +174,73 @@ class Converter: public BaseConverter {
 
 };
 
+
+template<auto Func>
+class ConverterFunc: public BaseConverter {
+	private:
+		template<typename SrcType, typename DstType>
+		struct ParamExtractor {
+			using Src = SrcType;
+			using Dst = DstType;
+		};
+
+		template<typename S, typename D>
+		static auto makeParamExtractor(ox::Error (*)(keel::Context&, S&, D&)) {
+			return ParamExtractor<S, D>{};
+		}
+
+	public:
+		using SrcType = decltype(makeParamExtractor(Func))::Src;
+		using DstType = decltype(makeParamExtractor(Func))::Dst;
+
+		[[nodiscard]]
+		constexpr ox::StringView srcTypeName() const noexcept final {
+			return ox::ModelTypeName_v<SrcType>;
+		}
+
+		[[nodiscard]]
+		constexpr int srcTypeVersion() const noexcept final {
+			return ox::ModelTypeVersion_v<SrcType>;
+		}
+
+		[[nodiscard]]
+		constexpr bool srcMatches(ox::StringViewCR pSrcTypeName, int pSrcTypeVersion) const noexcept final {
+			constexpr auto SrcTypeName = ox::requireModelTypeName<SrcType>();
+			constexpr auto SrcTypeVersion = ox::requireModelTypeVersion<SrcType>();
+			return pSrcTypeName == SrcTypeName
+			    && pSrcTypeVersion == SrcTypeVersion;
+		}
+
+		[[nodiscard]]
+		constexpr bool dstMatches(ox::StringViewCR dstTypeName, int dstTypeVersion) const noexcept final {
+			constexpr auto DstTypeName = ox::StringView{ox::requireModelTypeName<DstType>()};
+			constexpr auto DstTypeVersion = ox::requireModelTypeVersion<DstType>();
+			return dstTypeName == DstTypeName
+			    && dstTypeVersion == DstTypeVersion;
+		}
+
+		ox::Result<ox::UPtr<Wrap>> convertPtrToPtr(
+				keel::Context &ctx, Wrap &src) const noexcept final {
+			ox::Result<ox::UPtr<Wrap>> dst{makeWrap<DstType>()};
+			OX_RETURN_ERROR(convert(ctx, wrapCast<SrcType>(src), wrapCast<DstType>(*dst.value)));
+			return dst;
+		}
+
+		ox::Result<ox::UPtr<Wrap>> convertBuffToPtr(
+				keel::Context &ctx, ox::BufferView const&srcBuff) const noexcept final {
+			OX_REQUIRE_M(src, readAsset<SrcType>(srcBuff));
+			ox::Result<ox::UPtr<Wrap>> dst{makeWrap<DstType>()};
+			OX_RETURN_ERROR(convert(ctx, src, wrapCast<DstType>(*dst.value)));
+			return dst;
+		}
+
+	protected:
+		ox::Error convert(keel::Context &ctx, SrcType &src, DstType &dst) const noexcept {
+			return Func(ctx, src, dst);
+		}
+
+};
+
 ox::Result<ox::UPtr<Wrap>> convert(
 		keel::Context &ctx,
 		ox::BufferView const&srcBuffer,