refactor(melange): move stanza definition

src/dune_engine/dune_project.ml

@@ -345,12 +345,6 @@ end
 
 module Melange_syntax = struct
   let name = "melange"
-
-  let t =
-    Dune_lang.Syntax.create ~name ~desc:"support for Melange compiler"
-      [ ((0, 1), `Since (3, 6)) ]
-
-  let () = Extension.register_simple t (return [])
 end
 
 let explicit_extensions_map explicit_extensions =

src/dune_engine/dune_project.mli

@@ -202,5 +202,5 @@ val encode : t -> Dune_lang.t list
 val dune_site_extension : unit Extension.t
 
 module Melange_syntax : sig
-  val t : Dune_lang.Syntax.t
+  val name : string
 end

src/dune_rules/dir_status.ml

@@ -50,7 +50,7 @@ let get_include_subdirs stanzas =
 let find_module_stanza stanzas =
   List.find_map stanzas ~f:(fun stanza ->
       match stanza with
-      | Melange_emit { loc; _ }
+      | Melange_stanzas.Emit.T { loc; _ }
       | Library { buildable = { loc; _ }; _ }
       | Executables { buildable = { loc; _ }; _ }
       | Tests { exes = { buildable = { loc; _ }; _ }; _ } -> Some loc

src/dune_rules/dune_file.ml

@@ -455,7 +455,7 @@ module Mode_conf = struct
         ; ("native", return @@ Ocaml Native)
         ; ("best", return @@ Ocaml Best)
         ; ( "melange"
-          , Dune_lang.Syntax.since Dune_project.Melange_syntax.t (0, 1)
+          , Dune_lang.Syntax.since Melange_stanzas.syntax (0, 1)
             >>> return Melange )
         ]
 
@@ -2274,7 +2274,6 @@ type Stanza.t +=
   | Cram of Cram_stanza.t
   | Generate_sites_module of Generate_sites_module.t
   | Plugin of Plugin.t
-  | Melange_emit of Melange_stanzas.Emit.t
 
 module Stanzas = struct
   type t = Stanza.t list
@@ -2391,10 +2390,6 @@ module Stanzas = struct
       , let+ () = Dune_lang.Syntax.since Section.dune_site_syntax (0, 1)
         and+ t = Plugin.decode in
         [ Plugin t ] )
-    ; ( "melange.emit"
-      , let+ () = Dune_lang.Syntax.since Dune_project.Melange_syntax.t (0, 1)
-        and+ t = Melange_stanzas.Emit.decode in
-        [ Melange_emit t ] )
     ]
 
   let () = Dune_project.Lang.register Stanza.syntax stanzas

src/dune_rules/dune_file.mli

@@ -482,7 +482,6 @@ type Stanza.t +=
   | Cram of Cram_stanza.t
   | Generate_sites_module of Generate_sites_module.t
   | Plugin of Plugin.t
-  | Melange_emit of Melange_stanzas.Emit.t
 
 val stanza_package : Stanza.t -> Package.t option
 

src/dune_rules/gen_rules.ml

@@ -144,7 +144,7 @@ end = struct
       | true ->
         let+ () = Mdx.gen_rules ~sctx ~dir ~scope ~expander mdx in
         empty_none)
-    | Melange_emit mel ->
+    | Melange_stanzas.Emit.T mel ->
       let+ cctx, merlin =
         Melange_rules.setup_emit_cmj_rules ~dir_contents ~dir ~scope ~sctx
           ~expander mel
@@ -379,7 +379,7 @@ let under_melange_emit_target ~dir =
   | None -> None
   | Some stanzas ->
     List.find_map stanzas.stanzas ~f:(function
-      | Melange_emit mel ->
+      | Melange_stanzas.Emit.T mel ->
         let target_dir = Path.Build.relative parent mel.target in
         Option.some_if (Path.Build.equal target_dir dir) mel
       | _ -> None)
@@ -505,7 +505,7 @@ let gen_rules ~sctx ~dir components : Build_config.gen_rules_result Memo.t =
             | None -> subdirs
             | Some stanzas ->
               List.filter_map stanzas.stanzas ~f:(function
-                | Melange_emit mel -> Some mel.target
+                | Melange_stanzas.Emit.T mel -> Some mel.target
                 | _ -> None)
               |> String.Set.of_list |> String.Set.union subdirs
           in

src/dune_rules/melange_stanzas.ml

@@ -20,6 +20,8 @@ module Emit = struct
     ; javascript_extension : string
     }
 
+  type Stanza.t += T of t
+
   let decode_lib =
     let+ loc = loc
     and+ t =
@@ -125,3 +127,12 @@ module Emit = struct
        ; modules_without_implementation
        })
 end
+
+let syntax =
+  Dune_lang.Syntax.create ~name:Dune_project.Melange_syntax.name
+    ~desc:"support for Melange compiler"
+    [ ((0, 1), `Since (3, 6)) ]
+
+let () =
+  Dune_project.Extension.register_simple syntax
+    (return [ ("melange.emit", Emit.decode >>| fun x -> [ Emit.T x ]) ])

src/dune_rules/melange_stanzas.mli

@@ -20,5 +20,9 @@ module Emit : sig
     ; javascript_extension : string
     }
 
+  type Stanza.t += T of t
+
   val decode : t Dune_lang.Decoder.t
 end
+
+val syntax : Syntax.t

src/dune_rules/ml_sources.ml

@@ -378,7 +378,7 @@ let modules_of_stanzas dune_file ~dir ~scope ~lookup_vlib ~modules =
           Modules_group.relocate_alias_module modules ~src_dir
         in
         Memo.return (`Executables (exes, modules, obj_dir))
-      | Melange_emit mel ->
+      | Melange_stanzas.Emit.T mel ->
         let modules =
           let modules =
             Modules_field_evaluator.eval ~modules ~stanza_loc:mel.loc

src/dune_rules/ocaml_flags.ml

@@ -95,7 +95,7 @@ module Spec = struct
     and+ native = field_oslu "ocamlopt_flags"
     and+ melange =
       field_oslu
-        ~check:(Dune_lang.Syntax.since Dune_project.Melange_syntax.t (0, 1))
+        ~check:(Dune_lang.Syntax.since Melange_stanzas.syntax (0, 1))
         "melange.compile_flags"
     in
     let specific = Lib_mode.Map.make ~byte ~native ~melange in