unikernel/duniverse/dune_/bin/format_dune_file.ml

@@ -0,0 +1,57 @@
+open Import
+
+let doc = "Format dune files."
+
+let man =
+  [ `S "DESCRIPTION"
+  ; `P
+      {|$(b,dune format-dune-file) reads a dune file and outputs a formatted
+           version. This is a low-level command, meant to implement editor
+           support for example. To reformat a dune project, see the "Automatic
+           formatting" section in the manual.|}
+  ]
+;;
+
+let info = Cmd.info "format-dune-file" ~doc ~man
+
+let format_file ~version ~input =
+  let with_input =
+    match input with
+    | Some path -> fun f -> Io.with_lexbuf_from_file path ~f
+    | None ->
+      fun f ->
+        Exn.protect
+          ~f:(fun () -> f (Lexing.from_channel stdin))
+          ~finally:(fun () -> close_in_noerr stdin)
+  in
+  match with_input Dune_lang.Format.parse with
+  | Sexps sexps ->
+    Format.fprintf
+      Format.std_formatter
+      "%a%!"
+      Pp.to_fmt
+      (Dune_lang.Format.pp_top_sexps ~version sexps)
+  | OCaml_syntax loc ->
+    (match input with
+     | None -> User_error.raise ~loc [ Pp.text "OCaml syntax is not supported." ]
+     | Some path -> Io.with_file_in path ~f:(fun ic -> Io.copy_channels ic stdout))
+;;
+
+let term =
+  let+ path_opt =
+    let docv = "FILE" in
+    let doc = "Path to the dune file to parse." in
+    Arg.(value & pos 0 (some path) None & info [] ~docv ~doc)
+  and+ version =
+    let docv = "VERSION" in
+    let doc = "Which version of Dune language to use." in
+    let default =
+      Dune_lang.Syntax.greatest_supported_version_exn Dune_lang.Stanza.syntax
+    in
+    Arg.(value & opt version default & info [ "dune-version" ] ~docv ~doc)
+  in
+  let input = Option.map ~f:Arg.Path.path path_opt in
+  format_file ~version ~input
+;;
+
+let command = Cmd.v info term