I'm sending a reply to a request over a chan X, where X is a struct. The request is a search operation, so ideally I'd like to be able to return either an X, or report it wasn't found.
This would be a task for a Maybe X in Haskell or an x option in OCaml. Is there any decent way to do this in Go? I'm not returning a pointer (as the original object I'm returning might be modified later), so I can't just return nil.
Edit: right now I'm making it a chan interface{} and either sending an X or nil, but this is ugly and defeats type-safety.
If you're using interface {} you're effectively returning a pointer now. Why not change interface {} to *X and make sure to return a copy of the object? If I understand your reasoning behind not using a chan *X, that is.
Another way would be to add an ok bool. You could either add it to X or wrap X, like struct {X; ok bool}
I use the pointer type, where:
Maybe X = *XNothing = nilJust x = &xI recently needed to represent an optional/maybe of a type where I didn't want to use a pointer and couldn't rely on the zero value. I ended up opting to write the below, which will wrap any type for you. It might fit your use case also.