bulk: add PoC of vim-like modular editor

1 files changed, 72 insertions, 0 deletions

diff --git a/lib/editorBuffer.ml b/lib/editorBuffer.ml
new file mode 100644
index 0000000..5104549
--- /dev/null
+++ b/lib/editorBuffer.ml
@@ -0,0 +1,72 @@
+open Base
+open Zipper
+open Util
+
+type kind = File of string | No_name | Scratch
+type error = No_such_file | Other
+type buffer = { kind : kind; content : (char zipper zipper, error) Result.t }
+type t = buffer
+
+let empty =
+  { kind = No_name; content = empty |> push_after empty |> Result.return }
+
+module Action = struct
+  let on_content f b = { b with content = Result.map ~f b.content }
+
+  let up, down, left, right =
+    let vertical f ?(n = 1) =
+      on_content (fun z ->
+          let col = focus_or ~default:Zipper.empty z |> left_length in
+          Fn.apply_n_times ~n f z |> map_focus (goto col))
+    and horizontal f ?(n = 1) =
+      Fn.apply_n_times ~n (map_focus f) |> on_content
+    in
+    (vertical left, vertical right, horizontal left, horizontal right)
+
+  let bol = map_focus far_left |> on_content
+  let eol = map_focus far_right |> on_content
+  let bof = far_left |> on_content
+  let eof = far_right |> on_content
+  let insert k = map_focus (push k) |> on_content
+  let delete_after ~n = Fn.apply_n_times ~n (map_focus pop_after) |> on_content
+  let delete_before ~n = Fn.apply_n_times ~n (map_focus pop) |> on_content
+  let delete_to_eol = map_focus (split &> fst) |> on_content
+  let delete_to_bol = map_focus (split &> snd) |> on_content
+  let delete_lines ~n = Fn.apply_n_times ~n pop_after |> on_content
+
+  let delete_lines_before ~n =
+    on_content (fun z -> pop_after z |> Fn.apply_n_times ~n:(n - 1) pop_before)
+
+  let newline =
+    let aux z =
+      let l1, l2 = focus_or ~default:Zipper.empty z |> split in
+      push_before l1 z |> map_focus (Fn.const l2)
+    in
+    on_content aux
+
+  (* let save_history_to ?(clear = true) r = () *)
+end
+
+let from_file f =
+  let lines = Stdio.In_channel.read_lines f in
+  let line_to_zipper l = String.to_list l |> Sequence.of_list |> of_seq in
+  let content = Sequence.(of_list lines |> map ~f:line_to_zipper) |> of_seq in
+  { kind = File f; content = Ok content }
+
+let cursor b =
+  let open Option in
+  let x = Result.(map ~f:left_length b.content |> ok |> value ~default:0)
+  and y =
+    Result.(map ~f:focus b.content |> ok)
+    |> join |> map ~f:left_length |> value ~default:0
+  in
+  (x, y)
+
+let view x y h w b =
+  match b.content with
+  | Error _ -> Sequence.empty
+  | Ok z ->
+      let cx, _ = cursor b in
+      context ~b:(cx - x) ~a:(x + h - cx) z
+      |> to_seq
+      |> Sequence.map ~f:(window ~from:y ~len:w)