First class support for private toplevel items

[bobzhang]

private let u = 3
private let {length} = module (List)
private external ..

Note private in expression is not needed

let u = {
  let a = b  // a is already private by the scope
}

[jfrolich]

When the OCaml version is upgraded this is already supported using:

open {
   let u = 3
   ...
}

Are you aware of that?

[bloodyowl]

Is it planned for modules too?

private module Styles = {
  // css in js declarations
}

would be pretty nice to have to detect dead code without needing an interface file sometimes

[jfrolich]

Is it planned for modules too?

private module Styles = {
  // css in js declarations
}

would be pretty nice to have to detect dead code without needing an interface file sometimes

This is also covered with the local open feature.

[bloodyowl]

This is also covered with the local open feature.

I feel like the DX would be better for beginners to have a private X vs open { X } though 🙂

[chenglou]

private would actually be a desugaring of that new inline open

[bobzhang]

Note I proposed private let instead of let private since it looks like the former is easier to implement

[dodomorandi]

Just a minor thing: did you consider the possibility of using a slightly shorter keyword, something like pvt? I imagine that in some contexts private could be used often, creating some sort of grammar noise. A shorter keyword would improve the situation. On the other hand, a private block would make this change unnecessary:

private {
    let u = 3
    let {length} = module (List)
    external ..
}

[bobzhang]

private is already a keyword used in other places

[chenglou]

private is already a keyword, so we'll reuse it. Won't create a new one. pvt is short but not that descriptive. (Old Reason syntax used pri for "private" in some places. Folks didn't like it)

private block won't do; you need to interleave some private and non-private lines, so that'll end up being lots of bulky blocks for one-line bindings.

[ryyppy]

Currently unsure if this topic is colliding with this RFC regarding private by default.

For backlog grooming reasons, we'll remove the PRIORITY:high tag for now.

[stale[bot]]

The rescript-lang/syntax repo is obsolete and will be archived soon. If this issue is still relevant, please reopen in the compiler repo (https://github.com/rescript-lang/rescript-compiler) or comment here to ask for it to be moved. Thank you for your contributions.