Better support for mli/rei only modules (#489)

Author: jeremiedimino

CHANGES.md

@@ -26,6 +26,8 @@ next
   directory can't see each other unless one of them depend on the
   other (#472)
 
+- Better support for mli/rei only modules (#490)
+
 1.0+beta17 (01/02/2018)
 -----------------------
 

doc/jbuild.rst

@@ -167,6 +167,16 @@ modules you want.
   build system. It is not for casual uses, see the `re2 library
   <https://github.com/janestreet/re2>`__ for an example of use
 
+- ``(modules_without_implementation <modules>)`` specifies a list of
+  modules that have only a ``.mli`` or ``.rei`` but no ``.ml`` or
+  ``.re`` file. Such modules are usually referred as *mli only
+  modules*. They are not officially supported by the OCaml compiler,
+  however they are commonly used. Such modules must only define
+  types. Since it is not reasonably possible for Jbuilder to check
+  that this is the case, Jbuilder requires the user to explicitly list
+  such modules to avoid surprises. ``<modules>`` must be a subset of
+  the modules listed in the ``(modules ...)`` field.
+
 Note that when binding C libraries, Jbuilder doesn't provide special support for
 tools such as ``pkg-config``, however it integrates easily with `configurator
 <https://github.com/janestreet/configurator>`__ by using ``(c_flags (:include
@@ -250,6 +260,9 @@ binary at the same place as where ``ocamlc`` was found, or when there is a
 - ``flags``, ``ocamlc_flags`` and ``ocamlopt_flags``. See the section about
    specifying `OCaml flags`_
 
+- ``(modules_without_implementation <modules>)`` is the same as the
+  corresponding field of `library`_
+
 executables
 -----------
 

src/context.ml

@@ -52,7 +52,8 @@ type t =
   ; opam_var_cache          : (string, string) Hashtbl.t
   ; natdynlink_supported    : bool
   ; ocamlc_config           : (string * string) list
-  ; version                 : string
+  ; version_string          : string
+  ; version                 : int * int * int
   ; stdlib_dir              : Path.t
   ; ccomp_type              : string
   ; c_compiler              : string
@@ -318,16 +319,16 @@ let create ~(kind : Kind.t) ~path ~base_env ~env_extra ~name ~merlin
     let get_path var = Path.absolute (get var) in
     let stdlib_dir = get_path "standard_library" in
     let natdynlink_supported = Path.exists (Path.relative stdlib_dir "dynlink.cmxa") in
-    let version = get "version" in
+    let version_string = get "version" in
+    let version = Scanf.sscanf version_string "%u.%u.%u" (fun a b c -> a, b, c) in
     let env, env_extra =
       (* See comment in ansi_color.ml for setup_env_for_colors. For OCaml < 4.05,
          OCAML_COLOR is not supported so we use OCAMLPARAM. OCaml 4.02 doesn't support
          'color' in OCAMLPARAM, so we just don't force colors with 4.02. *)
-      let ocaml_version = Scanf.sscanf version "%u.%u" (fun a b -> a, b) in
       if !Clflags.capture_outputs
       && Lazy.force Ansi_color.stderr_supports_colors
-      && ocaml_version > (4, 02)
-      && ocaml_version < (4, 05) then
+      && version >= (4, 03, 0)
+      && version <  (4, 05, 0) then
         let value =
           match get_env env "OCAMLPARAM" with
           | None -> "color=always,_"
@@ -401,6 +402,7 @@ let create ~(kind : Kind.t) ~path ~base_env ~env_extra ~name ~merlin
 
       ; stdlib_dir
       ; ocamlc_config = String_map.bindings ocamlc_config
+      ; version_string
       ; version
       ; ccomp_type              = get       "ccomp_type"
       ; c_compiler

src/context.mli

@@ -88,7 +88,8 @@ type t =
 
   ; (** Output of [ocamlc -config] *)
     ocamlc_config           : (string * string) list
-  ; version                 : string
+  ; version_string          : string
+  ; version                 : int * int * int
   ; stdlib_dir              : Path.t
   ; ccomp_type              : string
   ; c_compiler              : string