Consider providing some typedefs or newtypes for system identifiers

[HadrienG2]

Heim exposes various system identifiers as primitive types like i32 or string slices. It would be a nice polish touch if those identifiers could be referred to via more explicit type names. I'm not sure whether the full awkwardness of newtypes would be worthwhile though, maybe a typedef would be enough.

For a motivating example, BTreeMap<SessionID, Vec<ProcessID>> decidedly reads more clearly than BTreeMap<i32, Vec<i32>>.

[svartalf]

Do you have the specific example? There are typedefs in most of the places, so there is also a chance that you are hitting the rust-lang/rust#15823 bug.

[HadrienG2]

Well, session IDs and process IDs are two examples. Right now, the rustdoc renders this: https://docs.rs/heim/0.1.0-alpha.1/heim/host/os/linux/trait.UserExt.html .

And indeed, I see that they use typedefs in https://github.com/heim-rs/heim/blob/master/heim-host/src/os/linux.rs so... good old rustdoc type alias bug, I guess 🤷‍♀️

[HadrienG2]

I don't think the SessionId typedef is exposed yet by host::os::linux though. Maybe something worth thinking about.