feat: add partial chords to statusbar

4 files changed, 213 insertions, 168 deletions

diff --git a/lib/command.ml b/lib/command.ml
index 31e2ca2..74b616a 100644
--- a/lib/command.ml
+++ b/lib/command.ml
@@ -18,6 +18,7 @@ type operation =
 type scope = Line | To_bol | To_eol | Down | Left | Right | Up
 
 type command =
+  | Reset
   | Type of char
   | Simple of Key.t
   | Partial of Key.t
@@ -89,59 +90,57 @@ let is_instant_operation k = List.mem ~equal:Poly.equal instant_operation k
 
 let n_stream =
   let step s k =
-    let open Sequence.Step in
     match (s, k) with
-    | `start, Key '"' -> Yield { value = Partial k; state = `chord_reg_pre }
+    | `start, Key '"' -> (`chord_reg_pre, Partial k)
     (* Register *)
-    | `chord_reg_pre, Key c -> Yield { value = Partial k; state = `chord_reg c }
+    | `chord_reg_pre, Key c -> (`chord_reg c, Partial k)
     (* Count (first) *)
     | `start, Key n when Char.('1' <= n && n <= '9') ->
         let n = Char.to_int n - 48 in
-        Yield { value = Partial k; state = `chord_fst_n (None, n) }
+        (`chord_fst_n (None, n), Partial k)
     | `chord_reg r, Key n when Char.('1' <= n && n <= '9') ->
         let n = Char.to_int n - 48 in
-        Yield { value = Partial k; state = `chord_fst_n (Some r, n) }
+        (`chord_fst_n (Some r, n), Partial k)
     | `chord_fst_n (r, m), Key n when Char.('0' <= n && n <= '9') ->
         let n = (10 * m) + Char.to_int n - 48 in
-        Yield { value = Partial k; state = `chord_fst_n (r, n) }
+        (`chord_fst_n (r, n), Partial k)
     (* Instant operations *)
-    | `start, k when is_instant_operation k ->
-        Yield { value = shortcut (to_op k); state = `start }
+    | `start, k when is_instant_operation k -> (`start, shortcut (to_op k))
     | `chord_reg r, k when is_instant_operation k ->
-        Yield { value = shortcut ~r (to_op k); state = `start }
+        (`start, shortcut ~r (to_op k))
     | `chord_fst_n (r, n), k when is_instant_operation k ->
-        Yield { value = shortcut ?r ~n (to_op k); state = `start }
+        (`start, shortcut ?r ~n (to_op k))
     (* Chord operation (first) *)
     | `start, k when is_chord_operation k ->
-        Yield { value = Partial k; state = `chord_cmd (None, None, to_op k) }
+        (`chord_cmd (None, None, to_op k), Partial k)
     | `chord_reg r, k when is_chord_operation k ->
-        Yield { value = Partial k; state = `chord_cmd (Some r, None, to_op k) }
+        (`chord_cmd (Some r, None, to_op k), Partial k)
     | `chord_fst_n (r, n), k when is_chord_operation k ->
-        Yield { value = Partial k; state = `chord_cmd (r, Some n, to_op k) }
+        (`chord_cmd (r, Some n, to_op k), Partial k)
     (* Count (second) *)
     | `chord_cmd (r, n1, c), Key n when Char.('1' <= n && n <= '9') ->
         let n = Char.to_int n - 48 in
-        Yield { value = Partial k; state = `chord_snd_n (r, n1, c, n) }
+        (`chord_snd_n (r, n1, c, n), Partial k)
     | `chord_snd_n (r, n1, c, n2), Key n when Char.('0' <= n && n <= '9') ->
         let n2 = (10 * n2) + Char.to_int n - 48 in
-        Yield { value = Partial k; state = `chord_snd_n (r, n1, c, n2) }
+        (`chord_snd_n (r, n1, c, n2), Partial k)
     (* Chord operation (second) *)
     | `chord_cmd (r, n, c), k when is_chord_operation k && Poly.(c = to_op k) ->
-        Yield { value = chord ?r ?n1:n c Line; state = `start }
+        (`start, chord ?r ?n1:n c Line)
     | `chord_snd_n (r, n1, c, n2), k
       when is_chord_operation k && Poly.(c = to_op k) ->
-        Yield { value = chord ?r ?n1 c ~n2 Line; state = `start }
+        (`start, chord ?r ?n1 c ~n2 Line)
     (* Movement *)
     | (`start | `chord_reg _), k when is_simple_movement k ->
-        Yield { value = chord Noop (to_scope k); state = `start }
+        (`start, chord Noop (to_scope k))
     | `chord_fst_n (_, n), k when is_simple_movement k ->
-        Yield { value = chord ~n1:n Noop (to_scope k); state = `start }
+        (`start, chord ~n1:n Noop (to_scope k))
     | `chord_cmd (r, n, c), k when is_simple_movement k ->
-        Yield { value = chord ?r ?n1:n c (to_scope k); state = `start }
+        (`start, chord ?r ?n1:n c (to_scope k))
     | `chord_snd_n (r, n1, c, n2), k when is_simple_movement k ->
-        Yield { value = chord ?r ?n1 c ~n2 (to_scope k); state = `start }
+        (`start, chord ?r ?n1 c ~n2 (to_scope k))
     (* Catch-all rules *)
-    | `start, _ -> Yield { value = Simple k; state = `start }
-    | _, _ -> Skip { state = `start }
+    | `start, _ -> (`start, Simple k)
+    | _, _ -> (`start, Reset)
   in
-  Sequence.unfold_with ~init:`start ~f:step Key.stream
+  Sequence.folding_map ~init:`start ~f:step Key.stream
diff --git a/lib/editor.ml b/lib/editor.ml
index c34d558..230f13a 100644
--- a/lib/editor.ml
+++ b/lib/editor.ml
@@ -12,13 +12,13 @@ type editor = {
   cursor : cursor;
   buffer : Buffer.t option;
   rendered : bool;
-  pending : Key.t Sequence.t;
-  i_pending : Command.t Sequence.t;
-  n_pending : Command.t Sequence.t;
+  istream : Command.t Sequence.t;
+  nstream : Command.t Sequence.t;
   status_size : int;
   message : string option;
   message_timestamp : float;
   message_duration : float;
+  pending_command : string;
 }
 
 type t = editor
@@ -31,13 +31,13 @@ let init (c : Config.t) : editor =
     cursor = (1, 1);
     buffer = List.hd c.files |> Option.map ~f:Buffer.from_file;
     rendered = true;
-    pending = Key.stream;
-    i_pending = Command.i_stream;
-    n_pending = Command.n_stream;
+    istream = Command.i_stream;
+    nstream = Command.n_stream;
     status_size = 2;
     message = Some "Hello, control line!";
     message_timestamp = Unix.time ();
     message_duration = 5.;
+    pending_command = "";
   }
 
 let string_of_mode = function
@@ -80,8 +80,9 @@ let statusbar e =
       ~fill:' ' w
     |> invert
   and control =
-    let msg = Option.value ~default:"" e.message |> sequence_of_string in
-    spread ~l:msg ~fill:' ' w
+    let msg = Option.value ~default:"" e.message |> sequence_of_string
+    and cmd = e.pending_command |> sequence_of_string in
+    spread ~l:msg ~r:cmd ~fill:' ' w
   in
   Sequence.(take (of_list [ status; control ]) e.status_size)
 
@@ -187,6 +188,14 @@ module Action = struct
   let set_message m e =
     ((), { e with message = m; message_timestamp = Unix.time () })
 
+  let get_pending_command e = (e.pending_command, e)
+  let set_pending_command p e = ((), { e with pending_command = p })
+
+  let append_pending_command k =
+    let aux p = p ^ Key.to_string k in
+    get_pending_command >>| aux >>= set_pending_command
+
+  let clear_pending_command = set_pending_command ""
 
   let tick =
     let check_message_timestamp e =
@@ -285,6 +294,7 @@ let handle_insert_command =
       (Buffer.Action.move_left |> on_focused_buffer) *> set_mode Normal
   | Simple Page_down | Simple (Ctrl 'F') ->
       fun e ->
+        (* TODO consider using the buffer window size (i.e., subtract status_size) *)
         let (n, _), e = get_terminal_size e in
         on_focused_buffer (Buffer.Action.move_down ~n) e
   | Simple Page_up | Simple (Ctrl 'B') ->
@@ -305,151 +315,159 @@ let handle_insert_command =
   | Type k -> Buffer.Action.insert k |> on_focused_buffer
   | _ -> noop
 
-let handle_normal_command =
+let handle_normal_command c =
   let open Command in
   let open Action in
-  function
-  (* Movements *)
-  | Chord (_, n, Noop, _, Down) ->
-      Buffer.Action.move_down ?n |> on_focused_buffer
-  | Chord (_, n, Noop, _, Left) ->
-      Buffer.Action.move_left ?n |> on_focused_buffer
-  | Chord (_, n, Noop, _, Right) ->
-      Buffer.Action.move_right ?n |> on_focused_buffer
-  | Chord (_, n, Noop, _, Up) -> Buffer.Action.move_up ?n |> on_focused_buffer
-  | Chord (_, n, Noop, _, To_bol) ->
-      let n = Option.value ~default:1 n - 1 in
-      Buffer.Action.(move_down ~n &> bol) |> on_focused_buffer
-  | Chord (_, n, Noop, _, To_eol) ->
-      let n = Option.value ~default:1 n - 1 in
-      Buffer.Action.(move_down ~n &> eol) |> on_focused_buffer
-  | Simple Page_down | Simple (Ctrl 'F') ->
-      fun e ->
-        let (n, _), e = get_terminal_size e in
-        on_focused_buffer (Buffer.Action.move_down ~n) e
-  | Simple Page_up | Simple (Ctrl 'B') ->
-      fun e ->
-        let (n, _), e = get_terminal_size e in
-        on_focused_buffer (Buffer.Action.move_up ~n) e
-  | Simple (Ctrl 'D') ->
-      fun e ->
-        let (r, _), e = get_terminal_size e in
-        on_focused_buffer (Buffer.Action.move_down ~n:(r / 2)) e
-  | Simple (Ctrl 'U') ->
-      fun e ->
-        let (r, _), e = get_terminal_size e in
-        on_focused_buffer (Buffer.Action.move_up ~n:(r / 2)) e
-  (* Change *)
-  | Shortcut (_, n, Change) ->
-      let n = Option.value ~default:1 n - 1 in
-      (Buffer.Action.(
-         delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
-      |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  | Chord (_, n1, Change, n2, Line) ->
-      let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
-      (Buffer.Action.(delete_lines ~n &> bol &> delete_to_eol)
-      |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  | Chord (_, n1, Change, n2, Down) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      (Buffer.Action.(delete_lines ~n &> bol &> delete_to_eol)
-      |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  | Chord (_, n1, Change, n2, Left) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      (Buffer.Action.delete_before ~n |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  | Chord (_, n1, Change, n2, Right) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      (Buffer.Action.delete_after ~n |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  | Chord (_, n1, Change, n2, Up) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      (Buffer.Action.(bol &> delete_to_eol &> delete_lines_before ~n)
-      |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  | Chord (_, n1, Change, n2, To_bol) ->
-      let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
-      (Buffer.Action.(
-         delete_to_bol &> move_down &> delete_lines ~n &> move_up &> bol)
-      |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  | Chord (_, n1, Change, n2, To_eol) ->
-      let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
-      (Buffer.Action.(
-         delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
-      |> on_focused_buffer_or_new)
-      *> set_mode Insert
-  (* Delete *)
-  | Shortcut (_, n, Delete) ->
-      let n = Option.value ~default:1 n - 1 in
-      Buffer.Action.(
-        delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
-      |> on_focused_buffer_or_new
-  | Chord (_, n1, Delete, n2, Line) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      Buffer.Action.delete_lines ~n |> on_focused_buffer_or_new
-  | Chord (_, n1, Delete, n2, Down) ->
-      let n = Option.((value ~default:1 n1 * value ~default:1 n2) + 1) in
-      Buffer.Action.delete_lines ~n |> on_focused_buffer_or_new
-  | Chord (_, n1, Delete, n2, Left) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      Buffer.Action.delete_before ~n |> on_focused_buffer_or_new
-  | Shortcut (_, n, Erase_before) ->
-      let n = Option.(value ~default:1 n) in
-      Buffer.Action.delete_before ~n |> on_focused_buffer_or_new
-  | Chord (_, n1, Delete, n2, Right) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      Buffer.Action.delete_after ~n |> on_focused_buffer_or_new
-  | Shortcut (_, n, Erase_after) ->
-      let n = Option.(value ~default:1 n) in
-      Buffer.Action.delete_after ~n |> on_focused_buffer_or_new
-  | Chord (_, n1, Delete, n2, Up) ->
-      let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
-      Buffer.Action.(delete_lines ~n:1 &> delete_lines_before ~n)
-      |> on_focused_buffer_or_new
-  | Chord (_, n1, Delete, n2, To_bol) ->
-      let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
-      Buffer.Action.(
-        delete_to_bol &> move_down &> delete_lines ~n &> move_up &> bol)
-      |> on_focused_buffer_or_new
-  | Chord (_, n1, Delete, n2, To_eol) ->
-      let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
-      Buffer.Action.(
-        delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
-      |> on_focused_buffer_or_new
-  (* Join *)
-  | Shortcut (_, n, Join) ->
-      let n = Option.(value ~default:1 n) in
-      Buffer.Action.join_lines ~n |> on_focused_buffer_or_new
-  (* Quit *)
-  | Simple (Ctrl 'Q') -> quit 0
-  (* Misc *)
-  | Simple (Key 'A') ->
-      (Buffer.Action.eol |> on_focused_buffer_or_new) *> set_mode Insert
-  | Simple (Key 'a') ->
-      (Buffer.Action.move_right |> on_focused_buffer_or_new) *> set_mode Insert
-  (* | Key 'G' -> Buffer.Action.eof |> on_focused_buffer_or_new *)
-  (* | Key 'I' -> noop *)
-  | Simple (Key 'i') -> (Fn.id |> on_focused_buffer_or_new) *> set_mode Insert
-  (* | Key 's' -> *)
-  (*     (Buffer.Action.delete_after |> on_focused_buffer_or_new) *)
-  (* *> set_mode Insert *)
-  (* Debug *)
-  | Simple (Ctrl 'R') -> toggle_rendered
-  | _ -> noop
+  let update_command_cue =
+    match c with
+    | Partial k -> append_pending_command k
+    | _ -> clear_pending_command
+  and compute_action =
+    match c with
+    (* Movements *)
+    | Chord (_, n, Noop, _, Down) ->
+        Buffer.Action.move_down ?n |> on_focused_buffer
+    | Chord (_, n, Noop, _, Left) ->
+        Buffer.Action.move_left ?n |> on_focused_buffer
+    | Chord (_, n, Noop, _, Right) ->
+        Buffer.Action.move_right ?n |> on_focused_buffer
+    | Chord (_, n, Noop, _, Up) -> Buffer.Action.move_up ?n |> on_focused_buffer
+    | Chord (_, n, Noop, _, To_bol) ->
+        let n = Option.value ~default:1 n - 1 in
+        Buffer.Action.(move_down ~n &> bol) |> on_focused_buffer
+    | Chord (_, n, Noop, _, To_eol) ->
+        let n = Option.value ~default:1 n - 1 in
+        Buffer.Action.(move_down ~n &> eol) |> on_focused_buffer
+    | Simple Page_down | Simple (Ctrl 'F') ->
+        fun e ->
+          let (n, _), e = get_terminal_size e in
+          on_focused_buffer (Buffer.Action.move_down ~n) e
+    | Simple Page_up | Simple (Ctrl 'B') ->
+        fun e ->
+          let (n, _), e = get_terminal_size e in
+          on_focused_buffer (Buffer.Action.move_up ~n) e
+    | Simple (Ctrl 'D') ->
+        fun e ->
+          let (r, _), e = get_terminal_size e in
+          on_focused_buffer (Buffer.Action.move_down ~n:(r / 2)) e
+    | Simple (Ctrl 'U') ->
+        fun e ->
+          let (r, _), e = get_terminal_size e in
+          on_focused_buffer (Buffer.Action.move_up ~n:(r / 2)) e
+    (* Change *)
+    | Shortcut (_, n, Change) ->
+        let n = Option.value ~default:1 n - 1 in
+        (Buffer.Action.(
+           delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
+        |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    | Chord (_, n1, Change, n2, Line) ->
+        let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
+        (Buffer.Action.(delete_lines ~n &> bol &> delete_to_eol)
+        |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    | Chord (_, n1, Change, n2, Down) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        (Buffer.Action.(delete_lines ~n &> bol &> delete_to_eol)
+        |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    | Chord (_, n1, Change, n2, Left) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        (Buffer.Action.delete_before ~n |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    | Chord (_, n1, Change, n2, Right) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        (Buffer.Action.delete_after ~n |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    | Chord (_, n1, Change, n2, Up) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        (Buffer.Action.(bol &> delete_to_eol &> delete_lines_before ~n)
+        |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    | Chord (_, n1, Change, n2, To_bol) ->
+        let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
+        (Buffer.Action.(
+           delete_to_bol &> move_down &> delete_lines ~n &> move_up &> bol)
+        |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    | Chord (_, n1, Change, n2, To_eol) ->
+        let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
+        (Buffer.Action.(
+           delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
+        |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    (* Delete *)
+    | Shortcut (_, n, Delete) ->
+        let n = Option.value ~default:1 n - 1 in
+        Buffer.Action.(
+          delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
+        |> on_focused_buffer_or_new
+    | Chord (_, n1, Delete, n2, Line) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        Buffer.Action.delete_lines ~n |> on_focused_buffer_or_new
+    | Chord (_, n1, Delete, n2, Down) ->
+        let n = Option.((value ~default:1 n1 * value ~default:1 n2) + 1) in
+        Buffer.Action.delete_lines ~n |> on_focused_buffer_or_new
+    | Chord (_, n1, Delete, n2, Left) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        Buffer.Action.delete_before ~n |> on_focused_buffer_or_new
+    | Shortcut (_, n, Erase_before) ->
+        let n = Option.(value ~default:1 n) in
+        Buffer.Action.delete_before ~n |> on_focused_buffer_or_new
+    | Chord (_, n1, Delete, n2, Right) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        Buffer.Action.delete_after ~n |> on_focused_buffer_or_new
+    | Shortcut (_, n, Erase_after) ->
+        let n = Option.(value ~default:1 n) in
+        Buffer.Action.delete_after ~n |> on_focused_buffer_or_new
+    | Chord (_, n1, Delete, n2, Up) ->
+        let n = Option.(value ~default:1 n1 * value ~default:1 n2) in
+        Buffer.Action.(delete_lines ~n:1 &> delete_lines_before ~n)
+        |> on_focused_buffer_or_new
+    | Chord (_, n1, Delete, n2, To_bol) ->
+        let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
+        Buffer.Action.(
+          delete_to_bol &> move_down &> delete_lines ~n &> move_up &> bol)
+        |> on_focused_buffer_or_new
+    | Chord (_, n1, Delete, n2, To_eol) ->
+        let n = Option.((value ~default:1 n1 * value ~default:1 n2) - 1) in
+        Buffer.Action.(
+          delete_to_eol &> move_down &> delete_lines ~n &> move_up &> eol)
+        |> on_focused_buffer_or_new
+    (* Join *)
+    | Shortcut (_, n, Join) ->
+        let n = Option.(value ~default:1 n) in
+        Buffer.Action.join_lines ~n |> on_focused_buffer_or_new
+    (* Quit *)
+    | Simple (Ctrl 'Q') -> quit 0
+    (* Misc *)
+    | Simple (Key 'A') ->
+        (Buffer.Action.eol |> on_focused_buffer_or_new) *> set_mode Insert
+    | Simple (Key 'a') ->
+        (Buffer.Action.move_right |> on_focused_buffer_or_new)
+        *> set_mode Insert
+    (* | Key 'G' -> Buffer.Action.eof |> on_focused_buffer_or_new *)
+    (* | Key 'I' -> noop *)
+    | Simple (Key 'i') -> (Fn.id |> on_focused_buffer_or_new) *> set_mode Insert
+    (* | Key 's' -> *)
+    (*     (Buffer.Action.delete_after |> on_focused_buffer_or_new) *)
+    (* *> set_mode Insert *)
+    (* Debug *)
+    | Simple (Ctrl 'R') -> toggle_rendered
+    | _ -> noop
+  in
+  compute_action *> update_command_cue
 
 let handle_next_command m e =
   match m with
   | Insert -> (
-      match Sequence.next e.i_pending with
+      match Sequence.next e.istream with
       | None -> ((), e)
-      | Some (h, t) -> handle_insert_command h { e with i_pending = t })
+      | Some (h, t) -> handle_insert_command h { e with istream = t })
   | Normal -> (
-      match Sequence.next e.n_pending with
+      match Sequence.next e.nstream with
       | None -> ((), e)
-      | Some (h, t) -> handle_normal_command h { e with n_pending = t })
+      | Some (h, t) -> handle_normal_command h { e with nstream = t })
   | Control -> failwith "unimplemented"
 
 let handle_next_command =
diff --git a/lib/key.ml b/lib/key.ml
index d6656c5..22338f4 100644
--- a/lib/key.ml
+++ b/lib/key.ml
@@ -32,6 +32,25 @@ let of_char = function
   | c when Char.(c < ' ') -> Char.to_int c + 64 |> Char.of_int_exn |> ctrl
   | c -> Key c
 
+let to_string = function
+  | Arrow_down -> "<down>"
+  | Arrow_left -> "<left>"
+  | Arrow_right -> "<right>"
+  | Arrow_up -> "<up>"
+  | Backspace -> "<backspace>"
+  | Ctrl c -> Printf.sprintf "<c-%c>" c
+  | Delete -> "<delete>"
+  | End -> "<end>"
+  | Enter -> "<cr>"
+  | Esc -> "<esc>"
+  | Home -> "<home>"
+  | Key ' ' -> "<space>"
+  | Key c -> String.of_char c
+  | Nul -> "<nil>"
+  | Page_down -> "<pgdown>"
+  | Page_up -> "<pgup>"
+  | Tab -> "<tab>"
+
 let stream =
   let step s c =
     let open Sequence.Step in
diff --git a/lib/text.ml b/lib/text.ml
index ff1f727..218f5e1 100644
--- a/lib/text.ml
+++ b/lib/text.ml
@@ -8,3 +8,12 @@ let center ~fill n text =
   take (take padding len_p @ text @ padding) n
 
 let extend ~fill n text = take (text @ repeat fill) n
+
+let spread ?(l = empty) ?(lsize = length l) ?(c = empty) ?(csize = length c)
+    ?(r = empty) ?(rsize = length r) ~fill w =
+  let lpad = take (repeat fill) ((w / 2) - lsize - (csize / 2) - 1) in
+  let rpad = take (repeat fill) ((w / 2) - rsize - (csize / 2)) in
+  l @ lpad @ c @ rpad @ r
+
+let invert text = Terminal.(fmt_inverted_on @ text @ fmt_inverted_off)
+let bold text = Terminal.(fmt_bold_on @ text @ fmt_bold_off)