init

src/syntax.ml

@@ -0,0 +1,48 @@
+let ( let* ) o f = match o with Ok v -> f v | Error _ as e -> e
+let ( let+ ) o f = match o with Ok v -> Ok (f v) | Error _ as e -> e
+
+(* TODO use polymorphic variant for errors *)
+let unwrap_err_msg o = match o with Error (`Msg e) -> Error e | Ok v -> Ok v
+
+let list_iter f l =
+  let err = ref None in
+  try
+    List.iter
+      (fun v ->
+        match f v with
+        | Error _e as e ->
+            err := Some e;
+            raise Exit
+        | Ok () -> ())
+      l;
+    Ok ()
+  with Exit -> ( match !err with None -> assert false | Some v -> v)
+
+let list_map f l =
+  let err = ref None in
+  try
+    Ok
+      (List.map
+         (fun v ->
+           match f v with
+           | Error _e as e ->
+               err := Some e;
+               raise Exit
+           | Ok v -> v)
+         l)
+  with Exit -> ( match !err with None -> assert false | Some v -> v)
+
+let list_fold_left f acc l =
+  List.fold_left
+    (fun acc v ->
+      let* acc = acc in
+      f acc v)
+    (Ok acc) l
+
+let opt_list l =
+  match (List.for_all Option.is_none l, List.for_all Option.is_some l) with
+  | _, true ->
+      let l = List.map Option.get l in
+      Ok (Some l)
+  | true, _ -> Ok None
+  | _, _ -> Error ()