Access property by path

This example demonstrates that FReader/FWriter can be used standalone, without FDcSerializer/FDcDeserializer.

UE built-in module PropertyPath allow accessing nested object properties by a path like Foo.Bar.Baz:

• DcPropertyPathAccess.h
• DcPropertyPathAccess.cpp

// DataConfigExtra/Private/DataConfig/Extra/Types/DcPropertyPathAccess.cpp
FString Str;
UTEST_TRUE("...", PropertyPathHelpers::GetPropertyValue(Outer, TEXT("StructRoot.Middle.InnerMost.StrField"), Str));
UTEST_TRUE("...", Str == TEXT("Foo"));

UTEST_TRUE("...", PropertyPathHelpers::SetPropertyValue(Outer, TEXT("StructRoot.Middle.InnerMost.StrField"), FString(TEXT("Bar"))));
UTEST_TRUE("...", Outer->StructRoot.Middle.InnerMost.StrField == TEXT("Bar"));

We implemented a pair of methods DcExtra::GetDatumPropertyByPath/SetDatumPropertyByPath with FDcPropertyReader:

// DataConfigExtra/Private/DataConfig/Extra/Types/DcPropertyPathAccess.cpp
UTEST_TRUE("...", CheckStrPtr(GetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.Middle.InnerMost.StrField"), TEXT("Foo")));
UTEST_TRUE("...", CheckStrPtr(GetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.Arr.0.StrField"), TEXT("Bar0")));
UTEST_TRUE("...", CheckStrPtr(GetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.Arr.1.StrField"), TEXT("Bar1")));
UTEST_TRUE("...", CheckStrPtr(GetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.NameMap.FooKey.StrField"), TEXT("FooValue")));

UTEST_TRUE("...", SetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.Middle.InnerMost.StrField", TEXT("AltFoo")));
UTEST_TRUE("...", SetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.Arr.0.StrField", TEXT("AltBar0")));
UTEST_TRUE("...", SetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.Arr.1.StrField", TEXT("AltBar1")));
UTEST_TRUE("...", SetDatumPropertyByPath<FString>(FDcPropertyDatum(Outer), "StructRoot.NameMap.FooKey.StrField", TEXT("AltFooValue")));

Comparing to PropertyPathHelpers these new ones support Array and Map, and support USTRUCT roots. We're missing some features like expanding weak/lazy object references but it should be easy to implement.

Remember that we have bundled JSON/MsgPack reader/writers that can also be used standalone.