From 75b64b7dfad9ce659d91128fb49773dfa78926ee Mon Sep 17 00:00:00 2001
From: Patrick Ferris <patrick@sirref.org>
Date: Mon, 3 Aug 2026 15:00:33 +0100
Subject: [PATCH] Add hint to unix backend

---
 example/unix/main.ml    |  8 ++++++--
 src/bruit.ml            | 14 --------------
 src/unix/bruit_unix.ml  | 19 +++++++++++++++----
 src/unix/bruit_unix.mli |  1 +
 4 files changed, 22 insertions(+), 20 deletions(-)

diff --git a/example/unix/main.ml b/example/unix/main.ml
index a9b449e..76f0f83 100644
--- a/example/unix/main.ml
+++ b/example/unix/main.ml
@@ -6,12 +6,16 @@ let history prefix =
 
 let complete s =
   match String.get s 0 with
-  | 'h' -> [ "hello"; "hello there" ]
+  | 'h' -> [ "hello"; "hello there"; "heya" ]
   | _ | (exception Invalid_argument _) -> []
 
+let hint = function
+  | "h" | "he" | "hel" -> Some ("hello", `Fg `Cyan)
+  | _ -> None
+
 let () =
   Fmt_tty.setup_std_outputs ();
-  let ctx = Bruit_unix.stdctx () in
+  let ctx = Bruit_unix.stdctx ~hint () in
   let rec loop sys_break =
     let prompt =
       if sys_break then "[\x1b[31m130\x1b[0m] \x1b[33m>>\x1b[0m "
diff --git a/src/bruit.ml b/src/bruit.ml
index 8193e19..92167d1 100644
--- a/src/bruit.ml
+++ b/src/bruit.ml
@@ -259,20 +259,6 @@ let utf8_prev_char_len s off =
   in
   loop (off - 1)
 
-let _refresh_with_hints ~pwidth ~ab (state : State.t) =
-  let buf_width = utf8_display_width state state.buf state.len in
-  if pwidth + buf_width < state.cols then
-    begin match state.hint (State.buf state |> Bytes.to_string) with
-    | None -> ()
-    | Some (hint, style) ->
-        let () =
-          Format.fprintf Format.str_formatter "%a"
-            Fmt.(styled style string)
-            hint
-        in
-        Buffer.add_string ab (Format.flush_str_formatter ())
-    end
-
 let refresh_line_with_completions (state : State.t) lcs =
   if state.completion_idx < List.length lcs then
     let saved_state = state in
diff --git a/src/unix/bruit_unix.ml b/src/unix/bruit_unix.ml
index 9ade011..2a2d75c 100644
--- a/src/unix/bruit_unix.ml
+++ b/src/unix/bruit_unix.ml
@@ -39,7 +39,17 @@ let utf8_next_char_len s off =
   Bytes.get_utf_8_uchar s off
   |> Uchar.utf_decode_uchar |> Uchar.utf_8_byte_length
 
-let render ofd = function
+let refresh_with_hints ~hint ~ab buf =
+  begin match hint (buf |> Bytes.to_string) with
+  | None -> ()
+  | Some (hint, style) ->
+      let () =
+        Format.fprintf Format.str_formatter "%a" Fmt.(styled style string) hint
+      in
+      Buffer.add_string ab (Format.flush_str_formatter ())
+  end
+
+let render ~hint ofd = function
   | Bruit.Clear_screen ->
       let b = Bytes.of_string "\x1b[H\x1b[2J" in
       let _ : int = write ofd b ~off:0 ~len:(Bytes.length b) in
@@ -71,7 +81,7 @@ let render ofd = function
       Buffer.add_bytes ab prompt;
       Buffer.add_bytes ab (Bytes.sub buf 0 buf_len);
 
-      (* refresh_with_hints ~pwidth:state.len ~ab state; *)
+      refresh_with_hints ~hint ~ab (Bytes.sub buf 0 buf_len);
 
       (* Erase to the right *)
       Buffer.add_string ab "\x1b[0K";
@@ -82,11 +92,12 @@ let render ofd = function
       let _ : int = write ofd bs ~off:0 ~len:(Bytes.length bs) in
       ()
 
-let stdctx ?(stdin = Unix.stdin) ?(stdout = Unix.stdout) () =
+let stdctx ?(stdin = Unix.stdin) ?(stdout = Unix.stdout) ?(hint = fun _ -> None)
+    () =
   let read () = read stdin in
   let next_key () = Bruit.key read in
   let enter_raw_mode = enter_raw_mode stdin in
   let exit_raw_mode = exit_raw_mode stdin in
   Bruit.make_ctx ~next_key ~enter_raw_mode ~exit_raw_mode
     ~get_columns:Terminal.Size.get_columns
-    ~guess_printed_width:Terminal.guess_printed_width (render stdout)
+    ~guess_printed_width:Terminal.guess_printed_width (render ~hint stdout)
diff --git a/src/unix/bruit_unix.mli b/src/unix/bruit_unix.mli
index ac52d67..195548d 100644
--- a/src/unix/bruit_unix.mli
+++ b/src/unix/bruit_unix.mli
@@ -5,6 +5,7 @@
 val stdctx :
   ?stdin:Unix.file_descr ->
   ?stdout:Unix.file_descr ->
+  ?hint:(string -> (string * Fmt.style) option) ->
   unit ->
   Unix.terminal_io Bruit.ctx
 (** [stdctx ()] will by default use {! Unix.stdin} and {! Unix.stdout}. It is up
-- 
2.51.2