Split Preproressing.pp_and... in two functions

Signed-off-by: Jeremie Dimino <jeremie@dimino.org>

src/gen_rules.ml

@@ -555,8 +555,8 @@ module Gen(P : Install_rules.Params) = struct
     in
     (* Preprocess before adding the alias module as it doesn't need
        preprocessing *)
-    let modules =
-      Preprocessing.pp_and_lint_modules sctx ~dir ~dep_kind ~modules ~scope
+    let pp =
+      Preprocessing.make sctx ~dir ~dep_kind ~scope
         ~preprocess:lib.buildable.preprocess
         ~preprocessor_deps:
           (SC.Deps.interpret sctx ~scope ~dir
@@ -564,6 +564,7 @@ module Gen(P : Install_rules.Params) = struct
         ~lint:lib.buildable.lint
         ~lib_name:(Some lib.name)
     in
+    let modules = Preprocessing.pp_modules pp modules in
 
     let modules =
       match alias_module with
@@ -817,13 +818,16 @@ module Gen(P : Install_rules.Params) = struct
         SC.Deps.interpret sctx exes.buildable.preprocessor_deps
           ~scope ~dir
       in
-      Preprocessing.pp_and_lint_modules sctx ~dir ~dep_kind:Required ~modules
+      let pp =
+        Preprocessing.make sctx ~dir ~dep_kind:Required
           ~scope
           ~preprocess:exes.buildable.preprocess
           ~preprocessor_deps
           ~lint:exes.buildable.lint
           ~lib_name:None
       in
+      Preprocessing.pp_modules pp modules
+    in
 
     let programs =
       List.map exes.names ~f:(fun (loc, name) ->

src/preprocessing.ml

@@ -293,9 +293,9 @@ let lint_module sctx ~dir ~dep_kind ~lint ~lib_name ~scope = Staged.stage (
   fun ~(source : Module.t) ~ast ->
     Per_module.get lint source.name ~source ~ast)
 
-(* Generate rules to build the .pp files and return a new module map
-   where all filenames point to the .pp files *)
-let pp_and_lint_modules sctx ~dir ~dep_kind ~modules ~lint ~preprocess
+type t = (Module.t -> Module.t) Per_module.t
+
+let make sctx ~dir ~dep_kind ~lint ~preprocess
       ~preprocessor_deps ~lib_name ~scope =
   let preprocessor_deps =
     Build.memoize "preprocessor deps" preprocessor_deps
@@ -303,7 +303,6 @@ let pp_and_lint_modules sctx ~dir ~dep_kind ~modules ~lint ~preprocess
   let lint_module =
     Staged.unstage (lint_module sctx ~dir ~dep_kind ~lint ~lib_name ~scope)
   in
-  let preprocess =
   Per_module.map preprocess ~f:(function
     | Preprocess.No_preprocessing ->
       (fun m ->
@@ -359,6 +358,7 @@ let pp_and_lint_modules sctx ~dir ~dep_kind ~modules ~lint ~preprocess
                    ; A "-o"; Target dst
                    ; Ml_kind.ppx_driver_flag kind; Dep src
                    ])))))
-  in
+
+let pp_modules t modules =
   Module.Name.Map.map modules ~f:(fun (m : Module.t) ->
-    Per_module.get preprocess m.name m)
+    Per_module.get t m.name m)

src/preprocessing.mli

@@ -2,18 +2,25 @@
 
 open! Import
 
-(** Setup pre-processing and linting rules and return the list of
-    pre-processed modules *)
-val pp_and_lint_modules
+(** Preprocessing object *)
+type t
+
+val make
   :  Super_context.t
   -> dir:Path.t
   -> dep_kind:Build.lib_dep_kind
-  -> modules:Module.t Module.Name.Map.t
   -> lint:Jbuild.Preprocess_map.t
   -> preprocess:Jbuild.Preprocess_map.t
   -> preprocessor_deps:(unit, Path.t list) Build.t
   -> lib_name:string option
   -> scope:Scope.t
+  -> t
+
+(** Setup the preprocessing rules for the following modules and
+    returns the translated modules *)
+val pp_modules
+  :  t
+  -> Module.t Module.Name.Map.t
   -> Module.t Module.Name.Map.t
 
 (** Get a path to a cached ppx driver *)