feat: Provide lib to compile grader helper libraries

and facility to link them during the `build` step.

NOTE: the helper library is going to be included in every exercise. A
lighter approach could be to keep loading it separately, e.g. after
loading the cma/js file from a directory holding static content on the
server (and removing the `.cma` from the compilation line in
`precompile_exercise.ml`).

This will probably fit well once we include such a mechanism for loading
custom libraries as the prelude to exercises, the main difference being
that the latter will also need the `cmi` files.

Author: AltGr

META.learn-ocaml.template

@@ -0,0 +1,6 @@
+package "test_lib" (
+  directory = "test_lib"
+  version = "0.13.2"
+  description = "Learn-ocaml dependencies for automatic graders"
+  requires = "compiler-libs"
+)

src/grader/dune

@@ -168,20 +168,19 @@
 )
 
 ;; cmis that are needed to precompile the graders for exercises
-;; FIXME: now we install the libs through dune, so use that ??
 (install
- (section share)
+ (section lib)
  (package learn-ocaml)
  (files
-  (../ppx-metaquot/.ty.objs/byte/ty.cmi as grading_cmis/ty.cmi)
-  (../ppx-metaquot/.fun_ty.objs/byte/fun_ty.cmi as grading_cmis/fun_ty.cmi)
-;;  (.exercise_init.objs/byte/exercise_init.cmi as grading_cmis/exercise_init.cmi)
-  (.introspection_intf.objs/byte/introspection_intf.cmi as grading_cmis/introspection_intf.cmi)
-  (.pre_test.objs/byte/learnocaml_internal.cmi as grading_cmis/learnocaml_internal.cmi)
-  (.pre_test.objs/byte/pre_test.cmi as grading_cmis/pre_test.cmi)
-  (.learnocaml_report.objs/byte/learnocaml_report.cmi as grading_cmis/learnocaml_report.cmi)
-  (.pre_test.objs/byte/learnocaml_callback.cmi as grading_cmis/learnocaml_callback.cmi) ;;FIXME separate lib??
-  (.testing_dyn.objs/byte/test_lib.cmi as grading_cmis/test_lib.cmi))
+  (../ppx-metaquot/.ty.objs/byte/ty.cmi as test_lib/ty.cmi)
+  (../ppx-metaquot/.fun_ty.objs/byte/fun_ty.cmi as test_lib/fun_ty.cmi)
+;;  (.exercise_init.objs/byte/exercise_init.cmi as test_lib/exercise_init.cmi)
+  (.introspection_intf.objs/byte/introspection_intf.cmi as test_lib/introspection_intf.cmi)
+  (.pre_test.objs/byte/learnocaml_internal.cmi as test_lib/learnocaml_internal.cmi)
+  (.pre_test.objs/byte/pre_test.cmi as test_lib/pre_test.cmi)
+  (.learnocaml_report.objs/byte/learnocaml_report.cmi as test_lib/learnocaml_report.cmi)
+  (.pre_test.objs/byte/learnocaml_callback.cmi as test_lib/learnocaml_callback.cmi) ;;FIXME separate lib??
+  (.testing_dyn.objs/byte/test_lib.cmi as test_lib/test_lib.cmi))
 )
 
 

src/grader/learnocaml_internal.mli

@@ -0,0 +1,4 @@
+(* This interface is used to pre-compile modules for the toplevel, giving them
+   access to specific toplevel functions. It should not be made accessible to
+   the non-precompiled code running in the toplevel *)
+include Learnocaml_internal_intf.S

src/repo/learnocaml_precompile_exercise.ml

@@ -6,7 +6,7 @@ open Lwt.Infix
 let grading_cmis_dir, grading_ppx_dir =
   let prefix = Filename.dirname (Filename.dirname (Sys.executable_name)) in
   let ( / ) = Filename.concat in
-  ref (prefix/"share"/"learn-ocaml"/"grading_cmis"),
+  ref (prefix/"lib"/"learn-ocaml"/"test_lib"),
   ref (prefix/"lib"/"learn-ocaml"/"grading_ppx")
 
 let run ?dir cmd args =
@@ -91,7 +91,7 @@ let precompile ~exercise_dir =
        ~source:["test.ml"]
        ~target:"test.cmo"
      >>= fun () ->
-     ocamlc ~dir ["-a"]
+     ocamlc ~dir (["-a"] @ grader_flags)
        ~source:["test.cmo"]
        ~target:"test.cma"
      >>= fun () ->

src/toplevel/dune

@@ -10,7 +10,6 @@
 
 (library
  (name learnocaml_internal_intf)
- (public_name learn-ocaml.learnocaml_internal_intf)
  (wrapped false)
  (modules learnocaml_internal_intf)
  (modules_without_implementation learnocaml_internal_intf)

src/toplevel/learnocaml_internal_intf.mli

@@ -0,0 +1,4 @@
+(* (hidden) interface of the module that will be pre-loaded in the toplevel *)
+module type S = sig
+  val register_printer: string -> ('a -> 'b) -> unit
+end