Preliminary support for dune-project files

bin/main.ml

@@ -142,9 +142,12 @@ module Make(M : sig val which : which end) = struct
       let files = Sys.readdir dir |> Array.to_list |> String.Set.of_list in
       if String.Set.mem files "jbuild-workspace" then
         cont counter ~candidates:((0, dir, to_cwd) :: candidates) dir ~to_cwd
-      else if String.Set.exists files ~f:(fun fn ->
-        String.is_prefix fn ~prefix:"jbuild-workspace") then
+      else if M.which = Jbuilder &&
+              String.Set.exists files ~f:(fun fn ->
+                String.is_prefix fn ~prefix:"jbuild-workspace") then
         cont counter ~candidates:((1, dir, to_cwd) :: candidates) dir ~to_cwd
+      else if String.Set.mem files "dune-project" then
+        cont counter ~candidates:((2, dir, to_cwd) :: candidates) dir ~to_cwd
       else
         cont counter ~candidates dir ~to_cwd
     and cont counter ~candidates ~to_cwd dir =

doc/jbuild.rst

@@ -31,8 +31,8 @@ The following sections describe the available stanzas and their meaning.
 jbuild_version
 --------------
 
-``(jbuild_version 1)`` specifies that we are using the version 1 of
-the Jbuilder metadata format in this ``jbuild`` file.
+Deprecated. This stanza is no longer used and will be removed in the
+future.
 
 library
 -------

doc/project-layout-specification.rst

@@ -2,9 +2,10 @@
 Project Layout and Metadata Specification
 *****************************************
 
-A typical jbuilder project will have one or more ``<package>.opam`` file
-at toplevel as well as ``jbuild`` files wherever interesting things are:
-libraries, executables, tests, documents to install, etc...
+A typical jbuilder project will have a ```dune-project`` and one or
+more ``<package>.opam`` file at toplevel as well as ``jbuild`` files
+wherever interesting things are: libraries, executables, tests,
+documents to install, etc...
 
 It is recommended to organize your project so that you have exactly one
 library per directory. You can have several executables in the same
@@ -83,10 +84,10 @@ Examples
 
     this_is_an_atom_123'&^%!  ; this is a comment
     "another atom in an OCaml-string \"string in a string\" \123"
-    
+
     ; empty list follows below
     ()
-    
+
     ; a more complex example
     (
       (
@@ -103,6 +104,33 @@ Examples
 
 .. _opam-files:
 
+dune-project files
+==================
+
+These files are used to mark the root of projects as well as define
+project-wide parameters. These files are required to have a ``lang``
+which controls the names and contents of all configuration files read
+by Dune. The ``lang`` stanza looks like:
+
+.. code:: scheme
+
+          (lang dune 0.1)
+
+The 0.1 version of the language is exactly the same as the Jbuilder
+language. So to convert a Jbuilder project to Dune, simply write this
+file at the root of your project.
+
+Additionally, they can contains the following stanzas.
+
+name
+----
+
+Sets the name of the project:
+
+.. code:: scheme
+
+    (name <name>)
+
 <package>.opam files
 ====================
 

doc/usage.rst

@@ -15,7 +15,8 @@ jbuild-workspace
 ----------------
 
 The root of the current workspace is determined by looking up a
-``jbuild-workspace`` file in the current directory and parent directories.
+``jbuild-workspace`` or ``dune-project`` file in the current directory
+and parent directories.
 
 ``jbuilder`` prints out the root when starting if it is not the
 current directory:
@@ -50,6 +51,8 @@ this file.
 jbuild-workspace\*
 ------------------
 
+The following is deprecated and no longer works with ``dune``.
+
 In addition to the previous rule, if no ``jbuild-workspace`` file is found,
 ``jbuilder`` will look for any file whose name starts with ``jbuild-workspace``
 in ancestor directories. For instance ``jbuild-workspace.dev``. If such a file

src/dune_project.ml

@@ -0,0 +1,69 @@
+open Import
+open Sexp.Of_sexp
+
+type t =
+  { name : string
+  }
+
+let filename = "dune-project"
+
+type lang =
+  | Dune_0_1
+
+let lang =
+  let version ver =
+    match string ver with
+    | "0.1" -> Dune_0_1
+    | _ ->
+      of_sexp_error ver "unsupported version of the dune language"
+  in
+  let name =
+    enum
+      [ ("dune", ()) ]
+  in
+  sum
+    [ cstr "lang" (name @> version @> nil) (fun () v -> v) ]
+
+module Acc = struct
+  type t =
+    { name : string option
+    }
+
+  let init =
+    { name = None }
+end
+
+let load ~dir =
+  let fname = Path.to_string (Path.relative dir filename) in
+  let sexps = Sexp.load ~fname ~mode:Many in
+  let langs, sexps =
+    List.partition_map sexps ~f:(function
+      | List (loc, Atom (_, A "lang") :: _) as sexp ->
+        Left (lang sexp, loc)
+      | sexp -> Right sexp)
+  in
+  let _lang =
+    match langs with
+    | [] ->
+      Loc.fail (Loc.in_file fname)
+        "language not specified, you need to add (lang dune 0.1)"
+    | [(v, _)] -> v
+    | _ :: (_, loc) :: _ ->
+      Loc.fail loc "language specified too many times"
+  in
+  let acc =
+    List.fold_left sexps ~init:Acc.init ~f:(fun (acc : Acc.t) sexp ->
+      sum
+        [ cstr "lang" nil acc
+        ; cstr_loc "name" (string @> nil) (fun loc name ->
+            match acc.name with
+            | None -> { Acc.name = Some name }
+            | Some _ -> Loc.fail loc "name specified too many times")
+        ]
+        sexp)
+  in
+  { name =
+      match acc.name with
+      | Some s -> s
+      | None -> "_" ^ String.concat ~sep:"_" (Path.explode_exn dir)
+  }

src/dune_project.mli

@@ -0,0 +1,10 @@
+(** dune-project files *)
+
+type t =
+  { name : string
+  }
+
+val load : dir:Path.t -> t
+
+(** "dune-project" *)
+val filename : string

src/jbuild_load.ml

@@ -222,6 +222,31 @@ let load ?extra_ignored_subtrees ?(ignore_promoted_rules=false) () =
     |> Path.Map.of_list_multi
     |> Path.Map.map ~f:Scope_info.make
   in
+
+  let projects =
+    File_tree.fold ftree ~traverse_ignored_dirs:false ~init:[]
+      ~f:(fun dir acc ->
+        let path = File_tree.Dir.path dir in
+        let files = File_tree.Dir.files dir in
+        if String.Set.mem files Dune_project.filename then begin
+          (path, Dune_project.load ~dir:path) :: acc
+        end else
+          acc)
+    |> Path.Map.of_list_exn
+  in
+  let scopes =
+    Path.Map.merge scopes projects ~f:(fun path scope project ->
+      match scope, project with
+      | None, None -> assert false
+      | Some _, None -> scope
+      | None, Some { name } ->
+        Some { name     = Some name
+             ; packages = Package.Name.Map.empty
+             ; root     = path
+             }
+      | Some scope, Some { name } -> Some { scope with name = Some name })
+  in
+
   let scopes =
     if Path.Map.mem scopes Path.root then
       scopes