[PoC] support inline/nested records inside of externals

[zth]

Closes #7386

Mostly a PoC for now, to see if it was possible to just extend the current mechanisms to this. Feedback appreciated. There are still issues to solve, but this serves as a base for discussion/experimentation.

Support inline record definitions in externals:

@module("node:fs")
external readFileSync: (
  string,
  ~options: {
    encoding?: [#utf8 | #ascii | #base64],
    flag?: string,
    misc?: {
      mode?: int,
    },
  },
) => option<{filename: string, size: string}> = "fs.readFileSync"

[zth]

cc @nojaf

[pkg-pr-new]

Open in StackBlitz

rescript

npm i https://pkg.pr.new/rescript-lang/rescript@7791

@rescript/darwin-arm64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/darwin-arm64@7791

@rescript/darwin-x64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/darwin-x64@7791

@rescript/linux-arm64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/linux-arm64@7791

@rescript/linux-x64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/linux-x64@7791

@rescript/win32-x64

npm i https://pkg.pr.new/rescript-lang/rescript/@rescript/win32-x64@7791

commit: 9eaa9be

[tsnobip]

This would make writing bindings so much easier!!