Re: [Caml-list] js_of_ocaml with node

[Alain Frisch <alain@frisch.fr>]

On 04/28/2015 12:41 AM, Daniel Bünzli wrote:
> Le mardi, 28 avril 2015 à 00:03, Alain Frisch a écrit :
>> val mkdir: string -> int -> unit
>> [@@js.global "fs.mkdirAsync"]
>
> That should be "fs.mkdirSync".

Indeed!

> Just curious, how would the binding to the async fs.mkdir look like ?

Something like:

val mkdir_async: string -> int -> (js_exn option -> unit) -> unit
   [@@js.global "fs.mkdir"]

assuming some predefined bindings for js_exn.  (One could also decide to 
bind JS exception to OCaml's exn type, but the gain is not clear.)

There are other possible variations, such as making the mode optional:

val mkdir_async:
     string ->
     ?mode:(int[@js.default 0o777]) ->
     (js_exn option -> unit) ->
     unit
   [@@js.global "fs.mkdir"]


Here js.default forces the default value for the optional mode argument. 
  Without it, a missing value will send an `undefined` as the second 
argument (I don't know if fs.mkdir would be happy with it).  This is 
currently not supported, but one could also extend the tool to allow:

val mkdir_async:
     string ->
     ?mode:(int[@js.drop_if_missing]) ->
     (js_exn option -> unit) -> unit
   [@@js.global "fs.mkdir"]

so that the second argument is dropped in the JS call if not provided 
(but I don't see how to support that for OCaml callbacks in full 
generality, since the function needs to check the type of arguments to 
decide how to interpret them).


Alain