vim: add ocamllsp

flake.nix

@@ -34,12 +34,15 @@
 
       overlays.default = final: prev: {
         niphas-terminal = prev.alacritty;
-        niphas-web-browser = prev.qutebrowser;
+        niphas-web-browser = prev.firefox;
         niphas-file-browser = prev.pcmanfm;
         niphas-runner = prev.writers.writeDashBin "niphas-runner" "${prev.lib.getExe prev.rofi} -show run";
         niphas-locker = prev.swaylock;
+        niphas-screenshot = prev.writers.writeDashBin "niphas-screenshot" ''
+          ${prev.lib.getExe prev.grim} -g "$(${prev.lib.getExe prev.slurp})" - | ${prev.lib.getExe prev.satty} -f -
+        '';
 
-        niphas-editor = prev.callPackage packages/vim { };
+        niphas-editor = prev.lib.makeOverridable (prev.callPackage packages/vim) { };
         niphas-bar = import packages/ashell.nix {
           inherit (inputs) wrappers;
           pkgs = prev;
@@ -65,6 +68,28 @@
         niphas-set-wallpaper = prev.writers.writeDashBin "niphas-set-wallpaper" ''
           exec ${lib.getExe prev.swaybg} --mode fill --image ${toString final.niphas-wallpaper}
         '';
+
+        niphas-clipboard-watcher = prev.writers.writeDashBin "niphas-clipboard-watcher" ''
+          exec ${lib.getExe' prev.wl-clipboard "wl-paste"} -t text --watch ${lib.getExe prev.clipman} store
+        '';
+
+        niphas-clipman = prev.writers.writeDashBin "niphas-clipman" ''
+          exec ${lib.getExe prev.clipman} pick --tool rofi
+        '';
+
+        niphas-redshift =
+          let
+            geolocation = [
+              52.5244
+              13.4105
+            ];
+            latitude = builtins.elemAt geolocation 0;
+            longitude = builtins.elemAt geolocation 1;
+          in
+          prev.writers.writeDashBin "niphas-redshift" ''
+            exec ${lib.getExe prev.wlsunset} -l ${toString latitude} -L ${toString longitude}
+          '';
+
         vimv = prev.callPackage packages/vimv.nix { };
       };
 
@@ -82,6 +107,11 @@
             niphas-git
             niphas-niri
             niphas-editor
+            niphas-wallpaper
+            niphas-set-wallpaper
+            niphas-clipboard-watcher
+            niphas-clipman
+            niphas-redshift
             vimv
             ;
         }

modules/desktop.nix

@@ -28,13 +28,19 @@
     pkgs.wdisplays
     pkgs.nsxiv
     pkgs.xdg-desktop-portal
+    pkgs.clipman
     pkgs.xdg-desktop-portal-gnome
 
+    pkgs.rofi # to provide rofi-sensible-terminal
+
     pkgs.niphas-bar
     pkgs.niphas-file-browser
     pkgs.niphas-terminal
     pkgs.niphas-web-browser
     pkgs.niphas-set-wallpaper
+    pkgs.niphas-redshift
+    pkgs.niphas-screenshot
+    pkgs.niphas-clipboard-watcher
     pkgs.niphas-runner
     pkgs.niphas-locker
   ];

modules/nix.nix

@@ -13,6 +13,7 @@
   };
 
   programs.nix-index.enable = true;
+  programs.direnv.enable = true;
 
   environment.systemPackages = [
     pkgs.nil

modules/shell/tools.nix

@@ -1,6 +1,6 @@
 { pkgs, lib, ... }:
 let
-  isDarwin = lib.strings.hasSuffix "darwin" pkgs.system;
+  isDarwin = lib.strings.hasSuffix "darwin" pkgs.stdenv.hostPlatform.system;
 in
 {
   environment.systemPackages = [

packages/git.nix

@@ -1,4 +1,7 @@
-{ wrappers, pkgs }:
+{
+  wrappers,
+  pkgs,
+}:
 let
   git = wrappers.wrapperModules.git.apply {
     inherit pkgs;

packages/niri.nix

@@ -1,11 +1,6 @@
 {
   wrappers,
   pkgs,
-  screenshotPath ? null,
-  geolocation ? [
-    52.5244
-    13.4105
-  ],
 }:
 let
   lib = pkgs.lib;
@@ -17,169 +12,150 @@ let
 
   niri = wrappers.wrapperModules.niri.apply {
     inherit pkgs;
-    settings = builtins.foldl' lib.recursiveUpdate { } (
-      [
-        {
-          input = {
-            keyboard = {
-              xkb.layout = "de";
-              numlock = null;
-            };
-            touchpad = {
-              tap = null;
-              drag = true;
-            };
-            mouse = null;
-            trackpoint = null;
-            warp-mouse-to-focus = null;
-            focus-follows-mouse = null;
+    settings = builtins.foldl' lib.recursiveUpdate { } ([
+      {
+        input = {
+          keyboard = {
+            xkb.layout = "de";
+            xkb.variant = "T3";
+            xkb.options = "compose:caps";
+            numlock = null;
           };
-          layout = {
-            gaps = 8;
-            center-focused-column = "never";
-            preset-column-widths = [
-              { proportion = 1. / 3.; }
-              { proportion = 1. / 2.; }
-              { proportion = 2. / 3.; }
-            ];
-            default-column-width = {
-              proportion = 1. / 2.;
-            };
-            focus-ring = {
-              width = 2;
-              active-color = colors.active-color;
-              inactive-color = colors.inactive-color;
-            };
-            shadow = {
-              on = null;
-              draw-behind-window = true;
-              softness = 30;
-              spread = 5;
-              color = colors.shadow-color;
-            };
+          touchpad = {
+            tap = null;
+            drag = true;
           };
-          spawn-at-startup = [
-            (lib.getExe pkgs.niphas-bar)
-            (lib.getExe pkgs.niphas-set-wallpaper)
-          ]
-          ++ lib.optional (geolocation != null) (
-            let
-              latitude = builtins.elemAt geolocation 0;
-              longitude = builtins.elemAt geolocation 1;
-            in
-            [
-              (lib.getExe pkgs.wlsunset)
-              "-l"
-              (toString latitude)
-              "-L"
-              (toString longitude)
-            ]
-          );
-          hotkey-overlay.skip-at-startup = null;
-          prefer-no-csd = null;
-          animations.slowdown = 0.5; # twice as fast
-          binds =
-            let
-              wpctl = lib.getExe' pkgs.wireplumber "wpctl";
-            in
-            {
-              "Mod+Shift+Slash".show-hotkey-overlay = null;
-              "Mod+Y".spawn = lib.getExe pkgs.niphas-web-browser;
-              "Mod+T".spawn = lib.getExe pkgs.niphas-file-browser;
-              "Mod+Return".spawn = lib.getExe pkgs.niphas-terminal;
-              "Mod+D".spawn = lib.getExe pkgs.niphas-runner;
-              "Mod+Shift+W".spawn = lib.getExe pkgs.niphas-locker;
-
-              # TODO allow-when-locked
-              "XF86AudioRaiseVolume".spawn-sh = "${wpctl} set-volume @DEFAULT_AUDIO_SINK@ 0.1+ -l 1.0";
-              "XF86AudioLowerVolume".spawn-sh = "${wpctl} set-volume @DEFAULT_AUDIO_SINK@ 0.1-";
-              "XF86AudioMute".spawn-sh = "${wpctl} set-mute @DEFAULT_AUDIO_SINK@ toggle";
-              "XF86AudioMicMute".spawn-sh = "${wpctl} set-mute @DEFAULT_AUDIO_SOURCE@ toggle";
-              "XF86AudioPlay".spawn-sh = "${lib.getExe pkgs.playerctl} play-pause";
-              "XF86AudioStop".spawn-sh = "${lib.getExe pkgs.playerctl} stop";
-              "XF86AudioPrev".spawn-sh = "${lib.getExe pkgs.playerctl} previous";
-              "XF86AudioNext".spawn-sh = "${lib.getExe pkgs.playerctl} next";
-              "XF86MonBrightnessUp".spawn-sh = "${lib.getExe pkgs.brightnessctl} --class=backlight set +10%";
-              "XF86MonBrightnessDown".spawn-sh = "${lib.getExe pkgs.brightnessctl} --class=backlight set 10%-";
-
-              # TODO repeat=false
-              "Mod+O".toggle-overview = null;
-              "Mod+Shift+Q".close-window = null;
-
-              "Mod+H".focus-column-left = null;
-              "Mod+J".focus-window-or-workspace-down = null;
-              "Mod+K".focus-window-or-workspace-up = null;
-              "Mod+L".focus-column-right = null;
-              "Mod+Shift+H".move-column-left = null;
-              "Mod+Shift+J".move-window-down-or-to-workspace-down = null;
-              "Mod+Shift+K".move-window-up-or-to-workspace-up = null;
-              "Mod+Shift+L".move-column-right = null;
-              "Mod+Home".focus-column-first = null;
-              "Mod+End".focus-column-last = null;
-              "Mod+Shift+Home".move-column-to-first = null;
-              "Mod+Shift+End".move-column-to-last = null;
-
-              # TODO cooldown-ms=150
-              "Mod+WheelScrollDown".focus-workspace-down = null;
-              "Mod+WheelScrollUp".focus-workspace-up = null;
-              "Mod+Shift+WheelScrollDown".move-column-to-workspace-down = null;
-              "Mod+Shift+WheelScrollUp".move-column-to-workspace-up = null;
-
-              "Mod+WheelScrollRight".focus-column-right = null;
-              "Mod+WheelScrollLeft".focus-column-left = null;
-              "Mod+Shift+WheelScrollRight".move-column-right = null;
-              "Mod+Shift+WheelScrollLeft".move-column-left = null;
-
-              "Mod+1".focus-workspace = 1;
-              "Mod+2".focus-workspace = 2;
-              "Mod+3".focus-workspace = 3;
-              "Mod+4".focus-workspace = 4;
-              "Mod+5".focus-workspace = 5;
-              "Mod+6".focus-workspace = 6;
-              "Mod+7".focus-workspace = 7;
-              "Mod+8".focus-workspace = 8;
-              "Mod+9".focus-workspace = 9;
-              "Mod+Shift+1".move-window-to-workspace = 1;
-              "Mod+Shift+2".move-window-to-workspace = 2;
-              "Mod+Shift+3".move-window-to-workspace = 3;
-              "Mod+Shift+4".move-window-to-workspace = 4;
-              "Mod+Shift+5".move-window-to-workspace = 5;
-              "Mod+Shift+6".move-window-to-workspace = 6;
-              "Mod+Shift+7".move-window-to-workspace = 7;
-              "Mod+Shift+8".move-window-to-workspace = 8;
-              "Mod+Shift+9".move-window-to-workspace = 9;
-              "Mod+Tab".focus-workspace-previous = null;
-              "Mod+Comma".consume-window-into-column = null;
-              "Mod+Period".expel-window-from-column = null;
-              "Mod+R".switch-preset-column-width = null;
-              "Mod+F".maximize-column = null;
-              "Mod+Shift+F".fullscreen-window = null;
-              "Mod+Ctrl+F".expand-column-to-available-width = null;
-              "Mod+Minus".set-column-width = "-10%";
-              "Mod+Plus".set-column-width = "+10%";
-
-              "Mod+V".toggle-window-floating = null;
-              "Mod+Shift+V".switch-focus-between-floating-and-tiling = null;
-
-              # allow-inhibiting=false
-              "Mod+Escape".toggle-keyboard-shortcuts-inhibit = null;
-
-              "Mod+Shift+E".quit = null;
-              "Ctrl+Alt+Delete".quit = null;
-            };
-        }
-      ]
-      ++ lib.optional (screenshotPath != null) [
-        {
-          screenshot-path = screenshotPath;
-          binds = {
-            "Print".screenshot = null;
-            "Ctrl+Print".screenshot-screen = null;
-            "Alt+Print".screenshot-window = null;
+          mouse = null;
+          trackpoint = null;
+          warp-mouse-to-focus = null;
+          focus-follows-mouse = null;
+        };
+        layout = {
+          gaps = 8;
+          center-focused-column = "never";
+          preset-column-widths = [
+            { proportion = 1. / 3.; }
+            { proportion = 1. / 2.; }
+            { proportion = 2. / 3.; }
+          ];
+          default-column-width = {
+            proportion = 1. / 2.;
           };
-        }
-      ]
-    );
+          focus-ring = {
+            width = 2;
+            active-color = colors.active-color;
+            inactive-color = colors.inactive-color;
+          };
+          shadow = {
+            on = null;
+            draw-behind-window = true;
+            softness = 30;
+            spread = 5;
+            color = colors.shadow-color;
+          };
+        };
+        spawn-at-startup = [
+          (lib.getExe pkgs.niphas-bar)
+          (lib.getExe pkgs.niphas-set-wallpaper)
+          (lib.getExe pkgs.niphas-clipboard-watcher)
+          (lib.getExe pkgs.niphas-redshift)
+        ];
+        hotkey-overlay.skip-at-startup = null;
+        prefer-no-csd = null;
+        animations.slowdown = 0.5; # twice as fast
+        binds =
+          let
+            wpctl = lib.getExe' pkgs.wireplumber "wpctl";
+          in
+          {
+            "Mod+Shift+Slash".show-hotkey-overlay = null;
+            "Mod+Y".spawn = lib.getExe pkgs.niphas-web-browser;
+            "Mod+T".spawn = lib.getExe pkgs.niphas-file-browser;
+            "Mod+Return".spawn = lib.getExe pkgs.niphas-terminal;
+            "Mod+D".spawn = lib.getExe pkgs.niphas-runner;
+            "Mod+Shift+W".spawn = lib.getExe pkgs.niphas-locker;
+            "Print".spawn = lib.getExe pkgs.niphas-screenshot;
+            "Mod+Q".spawn = lib.getExe pkgs.niphas-clipman;
+
+            # TODO allow-when-locked
+            "XF86AudioRaiseVolume".spawn-sh = "${wpctl} set-volume @DEFAULT_AUDIO_SINK@ 0.1+ -l 1.0";
+            "XF86AudioLowerVolume".spawn-sh = "${wpctl} set-volume @DEFAULT_AUDIO_SINK@ 0.1-";
+            "XF86AudioMute".spawn-sh = "${wpctl} set-mute @DEFAULT_AUDIO_SINK@ toggle";
+            "XF86AudioMicMute".spawn-sh = "${wpctl} set-mute @DEFAULT_AUDIO_SOURCE@ toggle";
+            "XF86AudioPlay".spawn-sh = "${lib.getExe pkgs.playerctl} play-pause";
+            "XF86AudioStop".spawn-sh = "${lib.getExe pkgs.playerctl} stop";
+            "XF86AudioPrev".spawn-sh = "${lib.getExe pkgs.playerctl} previous";
+            "XF86AudioNext".spawn-sh = "${lib.getExe pkgs.playerctl} next";
+            "XF86MonBrightnessUp".spawn-sh = "${lib.getExe pkgs.brightnessctl} --class=backlight set +25%";
+            "XF86MonBrightnessDown".spawn-sh = "${lib.getExe pkgs.brightnessctl} --class=backlight set 25%-";
+
+            # TODO repeat=false
+            "Mod+O".toggle-overview = null;
+            "Mod+Shift+Q".close-window = null;
+
+            "Mod+H".focus-column-left = null;
+            "Mod+J".focus-window-or-workspace-down = null;
+            "Mod+K".focus-window-or-workspace-up = null;
+            "Mod+L".focus-column-right = null;
+            "Mod+Shift+H".move-column-left = null;
+            "Mod+Shift+J".move-window-down-or-to-workspace-down = null;
+            "Mod+Shift+K".move-window-up-or-to-workspace-up = null;
+            "Mod+Shift+L".move-column-right = null;
+            "Mod+Home".focus-column-first = null;
+            "Mod+End".focus-column-last = null;
+            "Mod+Shift+Home".move-column-to-first = null;
+            "Mod+Shift+End".move-column-to-last = null;
+
+            # TODO cooldown-ms=150
+            "Mod+WheelScrollDown".focus-workspace-down = null;
+            "Mod+WheelScrollUp".focus-workspace-up = null;
+            "Mod+Shift+WheelScrollDown".move-column-to-workspace-down = null;
+            "Mod+Shift+WheelScrollUp".move-column-to-workspace-up = null;
+
+            "Mod+WheelScrollRight".focus-column-right = null;
+            "Mod+WheelScrollLeft".focus-column-left = null;
+            "Mod+Shift+WheelScrollRight".move-column-right = null;
+            "Mod+Shift+WheelScrollLeft".move-column-left = null;
+
+            "Mod+1".focus-workspace = 1;
+            "Mod+2".focus-workspace = 2;
+            "Mod+3".focus-workspace = 3;
+            "Mod+4".focus-workspace = 4;
+            "Mod+5".focus-workspace = 5;
+            "Mod+6".focus-workspace = 6;
+            "Mod+7".focus-workspace = 7;
+            "Mod+8".focus-workspace = 8;
+            "Mod+9".focus-workspace = 9;
+            "Mod+Shift+1".move-window-to-workspace = 1;
+            "Mod+Shift+2".move-window-to-workspace = 2;
+            "Mod+Shift+3".move-window-to-workspace = 3;
+            "Mod+Shift+4".move-window-to-workspace = 4;
+            "Mod+Shift+5".move-window-to-workspace = 5;
+            "Mod+Shift+6".move-window-to-workspace = 6;
+            "Mod+Shift+7".move-window-to-workspace = 7;
+            "Mod+Shift+8".move-window-to-workspace = 8;
+            "Mod+Shift+9".move-window-to-workspace = 9;
+            "Mod+Tab".focus-workspace-previous = null;
+            "Mod+Comma".consume-window-into-column = null;
+            "Mod+Period".expel-window-from-column = null;
+            "Mod+R".switch-preset-column-width = null;
+            "Mod+F".maximize-column = null;
+            "Mod+Shift+F".fullscreen-window = null;
+            "Mod+Ctrl+F".expand-column-to-available-width = null;
+            "Mod+Minus".set-column-width = "-10%";
+            "Mod+Plus".set-column-width = "+10%";
+
+            "Mod+V".toggle-window-floating = null;
+            "Mod+Shift+V".switch-focus-between-floating-and-tiling = null;
+
+            # allow-inhibiting=false
+            "Mod+Escape".toggle-keyboard-shortcuts-inhibit = null;
+
+            "Mod+Shift+E".quit = null;
+            "Ctrl+Alt+Delete".quit = null;
+          };
+      }
+    ]);
   };
 in
 niri.wrapper

packages/vim/default.nix

@@ -1,5 +1,6 @@
 {
   neovim,
+  nodejs,
   vimPlugins,
   fetchFromGitHub,
   vimUtils,
@@ -14,28 +15,41 @@ neovim.override {
   configure = {
     vimAlias = true;
     viAlias = true;
-    customRC = ''
-      source ${./shared.vim}
-      source ${./init.vim}
-      let g:snippet_directory = '${vimPlugins.friendly-snippets}'
-      luafile ${./init.lua}
-    ''
-    + lib.optionalString (stylixColors != null) (
-      with stylixColors.withHashtag;
-      ''
-        luafile ${writeText "colors.lua" ''
-          require('base16-colorscheme').setup({
-            base00 = '${base00}', base01 = '${base01}', base02 = '${base02}', base03 = '${base03}',
-            base04 = '${base04}', base05 = '${base05}', base06 = '${base06}', base07 = '${base07}',
-            base08 = '${base08}', base09 = '${base09}', base0A = '${base0A}', base0B = '${base0B}',
-            base0C = '${base0C}', base0D = '${base0D}', base0E = '${base0E}', base0F = '${base0F}'
+    customRC =
+
+      lib.optionalString withCopilot (''
+        luafile ${writeText "copilot.lua" ''
+          require("copilot").setup({
+            suggestion = { enabled = false },
+            panel = { enabled = false },
+            copilot_node_command = '${lib.getExe nodejs}'
           })
+
+          require("copilot_cmp").setup()
         ''}
+      '')
+      + ''
+        source ${./shared.vim}
+        source ${./init.vim}
+        let g:snippet_directory = '${vimPlugins.friendly-snippets}'
+        luafile ${./init.lua}
       ''
-    )
-    + lib.optionalString (colorscheme != null) ''
-      colorscheme ${colorscheme}
-    '';
+      + lib.optionalString (stylixColors != null) (
+        with stylixColors.withHashtag;
+        ''
+          luafile ${writeText "colors.lua" ''
+            require('base16-colorscheme').setup({
+              base00 = '${base00}', base01 = '${base01}', base02 = '${base02}', base03 = '${base03}',
+              base04 = '${base04}', base05 = '${base05}', base06 = '${base06}', base07 = '${base07}',
+              base08 = '${base08}', base09 = '${base09}', base0A = '${base0A}', base0B = '${base0B}',
+              base0C = '${base0C}', base0D = '${base0D}', base0E = '${base0E}', base0F = '${base0F}'
+            })
+          ''}
+        ''
+      )
+      + lib.optionalString (colorscheme != null) ''
+        colorscheme ${colorscheme}
+      '';
     packages.nvim = with vimPlugins; {
       start = [
         base16-nvim
@@ -81,7 +95,10 @@ neovim.override {
           }
         )
       ]
-      ++ lib.optional withCopilot vimPlugins.copilot.nvim;
+      ++ lib.optionals withCopilot [
+        vimPlugins.copilot-lua
+        vimPlugins.copilot-cmp
+      ];
       opt = [
         csv
         dhall-vim

packages/vim/init.lua

@@ -19,17 +19,23 @@ cmp.setup({
       luasnip.lsp_expand(args.body)
     end,
   },
+  completion = {
+    autocomplete = { require("cmp.types").cmp.TriggerEvent.TextChanged },
+  },
   mapping = {
-    -- https://github.com/hrsh7th/nvim-cmp/wiki/Example-mappings#super-tab-like-mapping
+    ["<C-Space>"] = cmp.mapping.complete(),
+    ["<CR>"] = cmp.mapping.confirm({ select = true }),
+
     ["<Tab>"] = cmp.mapping(function(fallback)
       if cmp.visible() then
         cmp.select_next_item()
       elseif luasnip.expand_or_jumpable() then
         luasnip.expand_or_jump()
       else
-        fallback()
+        cmp.complete()
       end
     end, { "i", "s" }),
+
     ["<S-Tab>"] = cmp.mapping(function(fallback)
       if cmp.visible() then
         cmp.select_prev_item()
@@ -41,8 +47,11 @@ cmp.setup({
     end, { "i", "s" }),
   },
   sources = cmp.config.sources({
-    { name = "nvim_lsp" },
-    { name = "luasnip" },
+    { name = "copilot",  priority = 1000 },
+    { name = "nvim_lsp", priority = 800 },
+    { name = "luasnip",  priority = 700 },
+    { name = "path",     priority = 500 },
+    { name = "buffer",   priority = 300 },
   }),
 })
 
@@ -92,10 +101,11 @@ local language_servers = {
   pyright = {}, -- pyright
   -- tsserver = {}, -- typescript-language-server
   cssls = {},
-  elmls = {}, -- elm-language-server
-  gopls = {}, -- gopls
+  elmls = {},  -- elm-language-server
+  gopls = {},  -- gopls
   denols = {}, -- deno built in
   bashls = {}, -- bash-language-server
+  ocamllsp = {}, -- ocamllsp
   lua_ls = {
     Lua = {
       runtime = {
@@ -112,9 +122,9 @@ local language_servers = {
       },
     },
   },
-  hls = {}, -- haskell-language-server
-  html = {}, -- vscode-langservers-extracted
-  jsonls = {}, -- vscode-langservers-extracted
+  hls = {},     -- haskell-language-server
+  html = {},    -- vscode-langservers-extracted
+  jsonls = {},  -- vscode-langservers-extracted
   lemminx = {}, -- lemminx (for xml)
   nil_ls = {
     ["nil"] = {
@@ -122,10 +132,10 @@ local language_servers = {
         command = { "nixfmt" },
       },
     },
-  }, -- github:oxalica/nil
+  },                     -- github:oxalica/nil
   dhall_lsp_server = {}, -- dhall-lsp-server
   -- rnix = {}, -- rnix-lsp
-  jqls = {}, -- jq-lsp
+  jqls = {},             -- jq-lsp
   rust_analyzer = { ["rust-analyzer"] = {} },
   -- eslint = {},
   -- volar? vls?

packages/vim/init.vim

@@ -45,6 +45,17 @@ let g:netrw_winsize = 25
 call matchadd('colorcolumn', '\%101v', 100)
 highlight colorcolumn ctermbg=red
 
+fun! TrimWhitespace()
+  " Skip if the filetype is markdown
+  if &ft =~ 'markdown'
+    return
+  endif
+  let l:save = winsaveview()
+  keeppatterns %s/\s\+$//e
+  call winrestview(l:save)
+endfun
+autocmd BufWritePre * call TrimWhitespace()
+
 " undofile - This allows you to use undos after exiting and restarting
 " This, like swap and backups, uses .vim-undo first, then ~/.vim/undo
 " :help undo-persistence