create namespace in honor of directory structure

[Nymphium]

The below project seems to have namespaces with directories:

lib/
  data/
    data.ml
    foo/
      foo.ml
      foo_pat.ml
    bar/
      bar.ml
    biz/
      foo/
       ...
src/
  command_line.ml
  main.ml

however, dune supports only "flat" namespace.

In the above example, I must create a dune file like:

(library (name foo))

and Foo module can be referred anywhere.

When I rename foo to foo__ , although dune generates Foo__ module and data.ml can only refer the module, I cannot name foo__ to lib/data/biz/foo due to conflict with the flat namesmace.

Desired Behavior

I want dune to create modules with respect to the directory structure.
For example. the above project may contain "bundled" modules for each directories such as:

module Foo = struct
  module Foo (* or `include Foo` *)
  module Foo_pat
end
...
module Biz = struct
  module Biz
end

Or I can create such modules via generate_module in dune 2.8 ?
(* However, I wish I can get these modules without any settings ;) *)

[rgrinberg]

This is a duplicate of #1084. It's definitely something we'd like, but there are higher priority items right now.

[Nymphium]

Okay, thank you!