How can I merge two configs? about cpp-hocon

[MikaelSmith]

I don't recall exactly how this works; you may need to attempt dynamic_cast to config_value, which has a render method.

[MikaelSmith]

I think this is a case where being a port of a Java library gets messy. The interface - https://github.com/lightbend/config/blob/f92a4ee2f672c8254d87b27831d0903d3d0d6cc2/config/src/main/java/com/typesafe/config/ConfigMergeable.java - returns ConfigMergeable, but specific implementations can have more specific return values. In C++ I don't believe that's possible, so you need to attempt to cast to what you expect to get back. You should get back a config or config_value: https://puppetlabs.github.io/cpp-hocon/classhocon_1_1config__mergeable.html#a7b52c8c1cca8e617b34ea9eb439c8f59