Sum types in config file

[nxy7]

Hello, title of this question might be hard to understand so I'll give some example of what I'm asking about.
I'd like to have field that can be one of two types - string or struct. Example

cmd: |
   echo "test"
   echo "message"

Or

cmd:
   shell: zsh
   run: |
      echo "test"
      echo "message"

So there are two shapes of cmd field. Ideally I'd like to unmarshal config directly into config field that has the following structure

type Config struct {
   Cmd struct {
      Shell string
      Run string
   }
}

So in the first case i'd like it to unmarchal 'cmd' string into Config.Cmd.Run and provide some defaults myself. Second one (full config) is easy. I'd like to avoid 'any' type to have easier job working with Config later on, but if there's any way to have something like rust enum<String, Config> i'd gladly take that. Is that possible?

[nxy7]

I think I'll just make 2 Config structs: "Config" and "RawConfig". RawConfig will read data as 'any' type and construct type Cmd interface{} used in real config. Pain, but it'll do.