Improve: remove utility functions from Fmt_ast (ocaml-ppx#1059)

CHANGES.md

@@ -1,5 +1,6 @@
 ### (master)
 
+  + Improve: remove utility functions from Fmt_ast (#1059) (Guillaume Petiot)
   + Fix newlines and indentation in toplevel extension points (#1054) (Guillaume Petiot)
   + Fix placement of doc comments around extensions (#1052) (Jules Aguillon)
   + Improve: inline extensions that do not break (#1050) (Guillaume Petiot)

src/Conf.ml

@@ -2078,4 +2078,40 @@ and debug = !debug
 
 and check = !check
 
-let parse_line_in_attribute = parse_line ~from:`Attribute
+open Migrate_ast.Parsetree
+
+let update ?(quiet = false) c {attr_name= {txt; loc}; attr_payload; _} =
+  let result =
+    match txt with
+    | "ocamlformat" -> (
+      match attr_payload with
+      | PStr
+          [ { pstr_desc=
+                Pstr_eval
+                  ( { pexp_desc= Pexp_constant (Pconst_string (str, None))
+                    ; pexp_attributes= []
+                    ; _ }
+                  , [] )
+            ; _ } ] ->
+          parse_line ~from:`Attribute c str
+      | _ -> Error (`Malformed "string expected") )
+    | _ when String.is_prefix ~prefix:"ocamlformat." txt ->
+        Error
+          (`Malformed
+            (Format.sprintf "unknown suffix %S"
+               (String.chop_prefix_exn ~prefix:"ocamlformat." txt)))
+    | _ -> Ok c
+  in
+  match result with
+  | Ok conf -> conf
+  | Error error ->
+      let reason = function
+        | `Malformed line -> Format.sprintf "Invalid format %S" line
+        | `Misplaced (name, _) -> Format.sprintf "%s not allowed here" name
+        | `Unknown (name, _) -> Format.sprintf "Unknown option %s" name
+        | `Bad_value (name, value) ->
+            Format.sprintf "Invalid value for %s: %S" name value
+      in
+      let w = Warnings.Attribute_payload (txt, reason error) in
+      if (not c.quiet) && not quiet then Compat.print_warning loc w ;
+      c

src/Conf.mli

@@ -108,12 +108,6 @@ val debug : bool
 val check : bool
 (** Check whether the input files already are formatted. *)
 
-val parse_line_in_attribute :
-     t
-  -> string
-  -> ( t
-     , [ `Unknown of string * string
-       | `Bad_value of string * string
-       | `Malformed of string
-       | `Misplaced of string * string ] )
-     Result.t
+val update : ?quiet:bool -> t -> Migrate_ast.Parsetree.attribute -> t
+(** [update ?quiet c a] updates configuration [c] after reading attribute
+    [a]. [quiet] is false by default. *)