Refactor pretty-printing library to support styles

dune-project

@@ -23,7 +23,7 @@
    (cmdliner (>= "1.2.0"))
    (ezcurl (>= "0.2.4"))
    (minttea (>= "0.0.2"))
-   uuseg.string
+   uuseg
  )
  (tags
   (tui cli git github)))

github_tui.opam

@@ -15,7 +15,7 @@ depends: [
   "cmdliner" {>= "1.2.0"}
   "ezcurl" {>= "0.2.4"}
   "minttea" {>= "0.0.2"}
-  "uuseg.string"
+  "uuseg"
   "odoc" {with-doc}
 ]
 build: [

lib/pretty.ml

@@ -1,11 +1,16 @@
 (* A simple pretty printing combinator library *)
 
+type styles = ANSITerminal.style list
+
 type doc =
   | Empty
-  | Str of string
+  | Str of styles * string
   | Vertical of doc * doc
   | Horizontal of doc * doc
 
+let str string = Str ([], string)
+let fmt styles string = Str (styles, string)
+
 let row = function 
   | [] -> Empty
   | hd :: tl -> List.fold_left (fun l r -> Horizontal (l, r)) hd tl
@@ -14,25 +19,71 @@ let col = function
   | [] -> Empty
   | hd :: tl -> List.fold_left (fun l r -> Vertical (l, r)) hd tl
 
-let zip_lines l r =
-  let max_len_l = List.map String_extra.graphemes_len l |> List.fold_left max 0 in
-  let padding = String.make max_len_l ' ' in
+type chunk =
+  {
+    styles: styles;
+    string: string;
+  }
+
+let fmt_chunk {styles; string} =
+  ANSITerminal.sprintf styles "%s" string
+
+let mk_padding_chunk n =
+  let padding = String.make n ' ' in
+  {styles = []; string = padding}
+
+type line = 
+  { 
+    chunks: chunk list
+  }
+
+let fmt_line line =
+  line.chunks
+  |> List.map fmt_chunk
+  |> String.concat "" 
+
+let line_len line = 
+  List.fold_left
+    (fun acc {string; _} -> acc + String_extra.graphemes_len string)
+    0
+    line.chunks
+
+let zip_lines (l: line list) (r: line list) =
+  let max_len_l = List.map line_len l |> List.fold_left max 0 in
+
   let rec zip l r =
     match (l, r) with
     | (l, []) -> 
       l
+
     | ([], r) -> 
-      List.map (fun s -> padding ^ s) r
+      (* Optimisation: Add extra chunk only if padding is needed *)
+      if max_len_l > 0 then
+        let padding_chunk = mk_padding_chunk max_len_l in
+        List.map (fun line -> { chunks = padding_chunk :: line.chunks }) r
+      else
+        r
+
     | (hd_l :: tl_l, hd_r :: tl_r) ->
-      (String_extra.fill_right max_len_l hd_l ^ hd_r) :: zip tl_l tl_r
+      let left_len = line_len hd_l in
+
+      (* Optimisation: Combine chunks when left is already max len *)
+      if left_len >= max_len_l then
+        let new_line = { chunks = hd_l.chunks @ hd_r.chunks } in
+        new_line :: zip tl_l tl_r
+      else
+        let padding_chunk = mk_padding_chunk (max_len_l - left_len) in
+        let new_line = { chunks = hd_l.chunks @ [padding_chunk] @ hd_r.chunks } in
+        new_line :: zip tl_l tl_r
   in
+
   zip l r
 
 let rec render_to_lines = function
   | Empty ->
     []
-  | Str s ->
-    [s]
+  | Str (styles, string) ->
+    [{ chunks = [{styles; string}] }]
   | Vertical (top, bottom) ->
     render_to_lines top @ render_to_lines bottom
   | Horizontal (left, right) ->
@@ -41,4 +92,5 @@ let rec render_to_lines = function
 let render doc = 
   doc
   |> render_to_lines
+  |> List.map fmt_line
   |> String_extra.unlines

lib/tui/view.ml

@@ -1,24 +1,21 @@
-let fmt (styles : ANSITerminal.style list) : string -> string =
-  ANSITerminal.sprintf styles "%s"
+let style_repo =
+  ANSITerminal.([Bold; blue])
 
-let fmt_repo =
-  fmt ANSITerminal.([Bold; blue])
-
-let fmt_selected =
-  fmt ANSITerminal.([Bold; green])
+let style_selected =
+  ANSITerminal.([Bold; green])
 
 let tabs_section cur_tab =
   let open Pretty in
   let p_tab tab txt = 
     if cur_tab = tab
-    then Str (fmt_selected txt)
-    else Str txt
+    then fmt style_selected txt
+    else str txt
   in
   let sep = col
     [
-      Str " ";
-      Str " ";
-      Str "─";
+      str " ";
+      str " ";
+      str "─";
     ]
   in
   render @@ row
@@ -61,7 +58,7 @@ let file_widget ~max_name_len ~selected files =
   |> (fun lines -> [top] @ lines @ [bot])
   |> List.mapi (fun i s ->
     if i = hi_pos - 1 || i = hi_pos || i = hi_pos + 1
-      then fmt_selected s
+      then ANSITerminal.sprintf style_selected "%s" s
       else s
   )
   |> String_extra.unlines
@@ -81,7 +78,7 @@ let tab_content_section (model: Model.t) =
   | Issues | PullRequests -> ""
 
 let view (model: Model.t) =
-  let repo = fmt_repo model.repo in
+  let repo = ANSITerminal.sprintf style_repo "%s" model.repo in
   let tabs = tabs_section model.current_tab in
   let content = tab_content_section model in
   Format.sprintf