Casing in namespace is not respected

[nojaf]

In https://github.com/rescript-lang/experimental-rescript-webapi I noticed that bunx rewatch has slightly different output than bunx rescript.

Steps to reproduce:

• Create new project with rescript@12.0.0-alpha.4
• Add "namespace": "PkmnAPI", to rescript.json
• Create a function in one file and use it in another

ProduceAPI.res

let meh = (a: int) => {
  true
}

Consume.res

let b  = ProduceAPI.meh(1);

After bunx rescript I get:

// Generated by ReScript, PLEASE EDIT WITH CARE

import * as ProduceAPI$PkmnAPI from "./ProduceAPI.re.js";

let b = ProduceAPI$PkmnAPI.meh(1);

export {
  b,
}
/* b Not a pure module */

with bunx rewatch:

// Generated by ReScript, PLEASE EDIT WITH CARE

import * as ProduceAPI$PkmnApi from "./ProduceAPI.re.js";

let b = ProduceAPI$PkmnApi.meh(1);

export {
  b,
}
/* b Not a pure module */

ProduceAPI$PkmnAPI (rescript) versus ProduceAPI$PkmnApi (rewatch)

[rolandpeelen]

@jfrolich -- I think you did some work on namespacing. Care to have a look?

[tsnobip]

here is the culprit:

rewatch/src/config.rs

Line 315 in 39ea554

namespace => packages::Namespace::Namespace(namespace.to_string().to_case(Case::Pascal)),

while bsb doesn't actually convert to Pascal case but use a custom algorithm:

let namespace_of_package_name (s : string) : string =
  let len = String.length s in
  let buf = Ext_buffer.create len in
  let add capital ch =
    Ext_buffer.add_char buf (if capital then Char.uppercase_ascii ch else ch)
  in
  let rec aux capital off len =
    if off >= len then ()
    else
      let ch = String.unsafe_get s off in
      match ch with
      | 'a' .. 'z' | 'A' .. 'Z' | '0' .. '9' | '_' ->
        add capital ch;
        aux false (off + 1) len
      | '/' | '-' -> aux true (off + 1) len
      | _ -> aux capital (off + 1) len
  in
  aux true 0 len;
  Ext_buffer.contents buf

IMO it's a bit unfortunate that all this mangling happens for namespace, but if we don't want to introduce a breaking change we should likely make rewatch implement the same algorithm.