From 58997d9df7a65e180cbf6005f1736265ee38d041 Mon Sep 17 00:00:00 2001
From: Jeremie Dimino <jeremie@dimino.org>
Date: Wed, 20 Jun 2018 12:16:51 +0100
Subject: [PATCH] Present menhir as an extension

Signed-off-by: Jeremie Dimino <jeremie@dimino.org>
---
 CHANGES.md                                    |  3 ++
 src/dune_project.ml                           |  2 +-
 src/gen_rules.ml                              |  4 +-
 src/jbuild.ml                                 | 43 ++++++++++++++++---
 src/jbuild.mli                                |  3 +-
 .../test-cases/dune-project-edition/run.t     |  9 ++++
 .../test-cases/menhir/dune-project            |  1 +
 7 files changed, 56 insertions(+), 9 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index b30853d4..809467a0 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -81,6 +81,9 @@ next
 - Rename `files_recursively_in` to `source_tree` to make it clearer it
   doesn't include generated files (#899, fix #843, @diml)
 
+- Present the `menhir` stanza as an extension with its own version
+  (#..., @diml)
+
 1.0+beta20 (10/04/2018)
 -----------------------
 
diff --git a/src/dune_project.ml b/src/dune_project.ml
index 4695c231..d4900e46 100644
--- a/src/dune_project.ml
+++ b/src/dune_project.ml
@@ -259,7 +259,7 @@ module Extension = struct
         let parse_args p =
           let open Sexp.Of_sexp in
           let dune_project_edited = ref false in
-          parse p Univ_map.empty (List (Loc.none, []))
+          parse (enter p) Univ_map.empty (List (Loc.of_pos __POS__, []))
           |> List.map ~f:(fun (name, p) ->
             (name,
              return () >>= fun () ->
diff --git a/src/gen_rules.ml b/src/gen_rules.ml
index ea02f97b..0502cb4e 100644
--- a/src/gen_rules.ml
+++ b/src/gen_rules.ml
@@ -252,7 +252,7 @@ module Gen(P : Install_rules.Params) = struct
           let generated_files =
             List.concat_map stanzas ~f:(fun stanza ->
               match (stanza : Stanza.t) with
-              | Menhir menhir ->
+              | Menhir.T menhir ->
                 Menhir_rules.targets menhir
               | Rule rule ->
                 List.map (user_rule rule  ~dir ~scope) ~f:Path.basename
@@ -998,7 +998,7 @@ module Gen(P : Install_rules.Params) = struct
         | _ -> None));
     List.iter stanzas ~f:(fun stanza ->
       match (stanza : Stanza.t) with
-      | Menhir m ->
+      | Menhir.T m ->
         let cctx =
           match
             List.find_map (Menhir_rules.module_names m)
diff --git a/src/jbuild.ml b/src/jbuild.ml
index 4aa130d2..713755d9 100644
--- a/src/jbuild.ml
+++ b/src/jbuild.ml
@@ -1155,7 +1155,34 @@ module Menhir = struct
     ; loc        :  Loc.t
     }
 
+  let syntax =
+    Syntax.create
+      ~name:"menhir"
+      ~desc:"the menhir extension"
+      [ (1, 0) ]
+
   let t =
+    record
+      (field_o "merge_into" string >>= fun merge_into ->
+       field_oslu "flags" >>= fun flags ->
+       field "modules" (list string) >>= fun modules ->
+       Rule.Mode.field >>= fun mode ->
+       return
+         { merge_into
+         ; flags
+         ; modules
+         ; mode
+         ; loc = Loc.none
+         })
+
+  type Stanza.t += T of t
+
+  let () =
+    Dune_project.Extension.register syntax
+      (return [ "menhir", t >>| fun x -> [T x] ])
+
+  (* Syntax for jbuild files *)
+  let jbuild_syntax =
     record
       (field_o "merge_into" string >>= fun merge_into ->
        field_oslu "flags" >>= fun flags ->
@@ -1275,7 +1302,6 @@ type Stanza.t +=
   | Install     of Install_conf.t
   | Alias       of Alias_conf.t
   | Copy_files  of Copy_files.t
-  | Menhir      of Menhir.t
   | Documentation of Documentation.t
   | Env         of Env.t
 
@@ -1313,10 +1339,6 @@ module Stanzas = struct
       (loc >>= fun loc ->
        Rule.ocamlyacc >>| fun x ->
        rules (Rule.ocamlyacc_to_rule loc x))
-    ; "menhir",
-      (loc >>= fun loc ->
-       Menhir.t >>| fun x ->
-       [Menhir { x with loc }])
     ; "install",
       (Install_conf.t >>| fun x ->
        [Install x])
@@ -1347,6 +1369,17 @@ module Stanzas = struct
     ]
 
   let jbuild_parser =
+    (* The menhir stanza was part of the vanilla jbuild
+       syntax. Starting from Dune 1.0, it is presented as an
+       extension with its own version. *)
+    let stanzas =
+      stanzas @
+      [ "menhir",
+        (loc >>= fun loc ->
+         Menhir.jbuild_syntax >>| fun x ->
+         [Menhir.T { x with loc }])
+      ]
+    in
     Syntax.set syntax (0, 0) (sum stanzas)
 
   let () =
diff --git a/src/jbuild.mli b/src/jbuild.mli
index eacd8654..4bceafd4 100644
--- a/src/jbuild.mli
+++ b/src/jbuild.mli
@@ -303,6 +303,8 @@ module Menhir : sig
     ; mode       : Rule.Mode.t
     ; loc        : Loc.t
     }
+
+  type Stanza.t += T of t
 end
 
 module Alias_conf : sig
@@ -353,7 +355,6 @@ type Stanza.t +=
   | Install     of Install_conf.t
   | Alias       of Alias_conf.t
   | Copy_files  of Copy_files.t
-  | Menhir      of Menhir.t
   | Documentation of Documentation.t
   | Env         of Env.t
 
diff --git a/test/blackbox-tests/test-cases/dune-project-edition/run.t b/test/blackbox-tests/test-cases/dune-project-edition/run.t
index b40bafe0..abbe2aa3 100644
--- a/test/blackbox-tests/test-cases/dune-project-edition/run.t
+++ b/test/blackbox-tests/test-cases/dune-project-edition/run.t
@@ -7,3 +7,12 @@
   Info: creating file dune-project with this contents: (lang dune 1.0)
   $ cat dune-project
   (lang dune 1.0)
+
+Test that using menhir automatically update the dune-project file
+
+  $ echo '(library ((name x))) (menhir ((modules (x))))' >> src/dune
+  $ dune build
+  Info: appending this line to dune-project: (using menhir 1.0)
+  $ cat dune-project
+  (lang dune 1.0)
+  (using menhir 1.0)
diff --git a/test/blackbox-tests/test-cases/menhir/dune-project b/test/blackbox-tests/test-cases/menhir/dune-project
index de4fc209..0b09661e 100644
--- a/test/blackbox-tests/test-cases/menhir/dune-project
+++ b/test/blackbox-tests/test-cases/menhir/dune-project
@@ -1 +1,2 @@
 (lang dune 1.0)
+(using menhir 1.0)