Commands to interact with discocaml, associated IPC.

1 files changed, 23 insertions, 4 deletions

diff --git a/discocaml/main.ml b/discocaml/main.ml
index 2cc97b5..d9895f1 100644
--- a/discocaml/main.ml
+++ b/discocaml/main.ml
@@ -1,3 +1,14 @@
+type command = [ `Roundtrip ]
+
+let command_of_yojson = function
+  | `String "Roundtrip" -> Ok `Roundtrip
+  | _ -> Error "invalid command"
+
+type request = { expr : string; command : command }
+[@@deriving of_yojson { exn = true }]
+
+type response = [ `Error of string ] [@@deriving to_yojson { exn = true }]
+
 (*
 type position = [%import: Lexing.position] [@@deriving show]
 
@@ -14,14 +25,22 @@ type structure_item_desc = [%import: Parsetree.structure_item_desc]
 type structure_item = [%import: Parsetree.structure_item] [@@deriving show]
 type structure = [%import: Parsetree.structure] [@@deriving show]
 type toplevel_phrase = [%import: Parsetree.toplevel_phrase] [@@deriving show]
-*)
 
 let parse ~path (src : string) =
   let buf = Lexing.from_string src in
   buf.lex_start_p <- { buf.lex_start_p with pos_fname = path };
   buf.lex_curr_p <- { buf.lex_curr_p with pos_fname = path };
-  Parse.use_file buf
+  Parse.expression buf
+
+let () =
+  parse ~path:"main.ml" " print_endline ((\"Hello, world!\") )"
+  |> Format.fprintf Format.std_formatter "\n%a\n" Pprintast.expression
+*)
+
+let handle_request { expr; command } : response =
+  match command with `Roundtrip -> `Error ("TODO: " ^ expr)
 
 let () =
-  parse ~path:"main.ml" "let () = print_endline ((\"Hello, world!\") )"
-  |> List.iter (Pprintast.toplevel_phrase Format.std_formatter)
+  Yojson.Safe.from_channel stdin
+  |> request_of_yojson_exn |> handle_request |> response_to_yojson
+  |> Yojson.Safe.to_channel stdout