[nickknw]

Here is a practical everyday example where languages that can represent emptiness in the type system come in handy.

He ends up using pointers and mentions: "Using pointers also means that clients of the library will need to perform their own nil checks where appropriate to prevent panics."

Looking forward to using Rust :)

[carbocation]

> Using pointers also means that clients of the library will need to perform their own nil checks where appropriate to prevent panics.

In practice, as your Rust comment alludes, I find working with nil properties in Go types (used to shuffle between the DB and JSON) to be quite painful. I end up keeping track of a lot more state than I really want to, and errors can be introduced subtly.

In Go, you can usually use a type's zero value without doing anything special. But if that type contains any nil properties, you can't presume this anymore. If I have:

    type Thing struct {
        ID int
        Bad *string
    }

I then have to do nil checks in every method that might handle Thing, or I have to make it accessible only via functions which perform those checks for me in advance. Either way, much less convenient.