Is this a bug of a parser: `module M struct = ... end **in** document`?

[nekketsuuu]

Currently, it is necessary to write in before a document-type value in a .saty file even if there is only a definition of a module in "preamble".

@require: stdjareport

module M = struct
  let foo = 42
end

in  % <-- This `in` is necessary! Without this, SATySFi throws a syntax error.
document (|
  title = {example};
  author = {nekketsuuu};
|) '<
>

It looks strange a bit if I think like OCaml. Is this a design choice of SATySFi, or a bug of parser?

Environment

• Ubuntu 18.04
• OCaml 4.06.1
• SATySFi >=0.03 (current head 7ba1d05d258eac087e0439f3b731c96ca193c8a2)