feat: add ability to paste text from a register

Register are simplier than Vim register, in particular no register is
local to buffers.

1 files changed, 52 insertions, 3 deletions

diff --git a/lib/editorBuffer.ml b/lib/editorBuffer.ml
index c492b8b..295e6e7 100644
--- a/lib/editorBuffer.ml
+++ b/lib/editorBuffer.ml
@@ -61,12 +61,22 @@ module Action = struct
 
   (* let on_content_stored ?(register = '"') ?(append = false) f b = ... *)
 
-  let update_render_at_cursor b =
+  let update_render ?(before = false) ~n b =
     match b.content with
     | Error _ -> b
     | Ok c ->
-        let l = apply_focus_or ~default:Sequence.empty (to_seq &> render) c in
-        { b with rendered = swap_focus l b.rendered }
+        let step = if before then left else right in
+        let rec aux i r c =
+          if i = 0 then r
+          else
+            let default = Sequence.empty in
+            let l = apply_focus_or ~default (to_seq &> render) c in
+            let c' = step c and r' = swap_focus l r |> step in
+            aux (i - 1) r' c'
+        in
+        { b with rendered = aux n b.rendered c |> goto (left_length c) }
+
+  let update_render_at_cursor = update_render ~n:1
 
   let move_up ?(n = 1) =
     let change_content =
@@ -218,6 +228,45 @@ module Action = struct
     in
     change_content &> change_rendered &> update_render_at_cursor
 
+  let paste ?(before = false) ?(linewise = false) ?(n = 1) s =
+    let change_content =
+      if linewise then
+        let push = if before then push_before_seq else push_after_seq in
+        push (Sequence.map ~f:of_seq s) |> on_content
+      else
+        let aux z =
+          match Sequence.next s with
+          | None -> z
+          | Some (h, t) ->
+              let init =
+                let default = Zipper.(of_seq h |> far_right) in
+                map_focus_or ~default (push_before_seq h) z
+              and f z l =
+                let default = (Zipper.empty, Zipper.empty) in
+                let z1, z2 = apply_focus_or ~default split z in
+                z |> push_before z1 |> swap_focus z2
+                |> map_focus (push_before_seq l)
+              in
+              let folded = Sequence.fold ~init ~f t in
+              if before then folded
+              else
+                folded
+                |> Fn.apply_n_times ~n:(Sequence.length t) left
+                |> map_focus (Fn.apply_n_times ~n:(Sequence.length h) left)
+        in
+        on_content aux
+    and change_rendered =
+      if linewise then
+        let push = if before then push_before_seq else push_after_seq in
+        push (Sequence.map ~f:render s) |> on_rendered
+      else
+        let len = Sequence.length s in
+        let push = if before then push_before else push in
+        let aux z = Fn.apply_n_times ~n:(len - 1) (push Sequence.empty) z in
+        on_rendered aux &> update_render ~before ~n:len
+    in
+    Fn.apply_n_times ~n (change_content &> change_rendered)
+
   (* let save_history_to ?(clear = true) r = () *)
 end