diff --git a/hello.tex b/hello.tex
new file mode 100644
index 0000000..0edc68d
--- /dev/null
+++ b/hello.tex
@@ -0,0 +1,29 @@
+\documentclass{article}
+
+\begin{document}
+
+\section{Sample LaTeX Document with Math Symbols}
+
+Here are some math symbols and commands:
+
+1. Infinity: $\infty$
+2. Element of: $a \in A$
+3. Angle: $\angle ABC$
+4. Approximation: $a \approx b$
+5. Union: $A \cup B$
+6. Intersection: $A \cap B$
+7. Big union: $\bigcup_{i=1}^{n} A_i$
+8. Big intersection: $\bigcap_{i=1}^{n} A_i$
+9. Down arrow: $\downarrow$
+10. Double down arrow: $\Downarrow$
+11. Copyright symbol: $\copyright$
+12. Quadruple space: $a \qquad b$
+13. Empty set: $\emptyset$
+14. Aleph symbol: $\aleph$
+15. Product: $\prod_{i=1}^{n} a_i$
+16. Integration: $\int f(x) \, dx$
+17. Clubsuit: $\clubsuit$
+18. dot: $\dot{B}$
+
+\end{document}
+
diff --git a/native_configs/neovim/init.lua b/native_configs/neovim/init.lua
index 93f1511..808a379 100644
--- a/native_configs/neovim/init.lua
+++ b/native_configs/neovim/init.lua
@@ -53,10 +53,9 @@ vim.call('plug#begin')
 
 -- libs and dependencies
 WPlug('nvim-lua/plenary.nvim') -- The base of all plugins
-WPlug('MunifTanjim/nui.nvim')  -- For some .so or .dylib neovim UI action
-
-
--- plugins
+--
+--
+-- -- plugins
 WPlug('nvim-treesitter/nvim-treesitter')                     -- language parser engine for highlighting
 WPlug('nvim-treesitter/nvim-treesitter-textobjects')         -- more text objects
 WPlug('nvim-telescope/telescope.nvim', { branch = '0.1.x' }) -- file browser
@@ -101,10 +100,10 @@ WPlug('ThePrimeagen/harpoon')              -- 1-click through marked files per p
 WPlug('TimUntersberger/neogit')            -- Easy-to-see git status
 WPlug('folke/trouble.nvim')                -- File-grouped workspace diagnostics
 WPlug('tpope/vim-dispatch')                -- Allows quick build/compile/test vim commands
-WPlug('clojure-vim/vim-jack-in')           -- Clojure: ":Boot", ":Clj", ":Lein"
+-- WPlug('clojure-vim/vim-jack-in')           -- Clojure: ":Boot", ":Clj", ":Lein"
 WPlug('radenling/vim-dispatch-neovim')     -- Add support for neovim's terminal emulator
 -- WPlug('Olical/conjure')          -- REPL on the source for Clojure (and other LISPs)
-WPlug('gennaro-tedesco/nvim-jqx')          -- JSON formatter (use :Jqx*)
+WPlug('gennaro-tedesco/nvim-jqx')          -- JSON formatter (use :Jqx*).# TODO: supply chain?
 WPlug('kylechui/nvim-surround')            -- surrounds with tags/parenthesis
 WPlug('simrat39/rust-tools.nvim')          -- config rust-analyzer and nvim integration
 -- WPlug('tjdevries/sg.nvim')                 -- Cody and other cool sourcegraph stuffs
@@ -171,6 +170,14 @@ vim.api.nvim_create_autocmd({ "VimEnter" }, {
 
 vim.g.gruvbox_contrast_dark = "soft";
 vim.g.gruvbox_contrast_light = "soft";
+
+-- no more partial keystrokes, it's distracting
+vim.opt.showcmd = false;
+-- rely on lualine
+vim.opt.showmode = false;
+-- Suppress buffer/file written message
+vim.opt.shortmess = "atToOCF"
+
 vim.opt.ignorecase = true;
 vim.opt.smartcase = true;
 vim.opt.incsearch = true;
@@ -190,6 +197,72 @@ vim.opt.colorcolumn = "80";
 
 vim.opt.background = "dark";
 
+vim.opt.spelllang = "en_us";
+do -- selective spell-checking
+  local spellcheck = vim.api.nvim_create_augroup("SpellChecking", { clear = true })
+  vim.api.nvim_create_autocmd({ "FileType" }, {
+    group = spellcheck,
+    pattern = { "tex", "markdown", "md", },
+    callback = function() vim.opt_local.spell = true end,
+  })
+end
+
+do -- selective concealing/ligature {{{
+  g_docs = "docs"
+  group_map = {
+    plaintex = g_docs,
+    tex = g_docs,
+    markdown = g_docs,
+  }
+  conceal_by_mode = {
+    n = 2,
+    i = 0,
+    c = 2,
+    v = 0,
+  }
+
+  local group_handler = {
+    [g_docs] = function(_ft, _group)
+      vim.notify("group_handler: " .. vim.inspect({ _ft, _group }))
+      vim.opt_local.concealcursor = "n"
+      -- HACK: seems to be some lifetime racing issues here
+      -- Putting this inside `vim.schedule` puts this at the end of the
+      -- queue, so under the assumption that aucommands are done in an
+      -- event loop, we're sure that the current augroup invocation
+      -- would be done before syn is set
+      vim.schedule(function()
+        vim.opt_local.syn = "tex"
+      end)
+    end
+  }
+  local conceal = vim.api.nvim_create_augroup("Conceal", { clear = true })
+  vim.api.nvim_create_autocmd({ "FileType" }, {
+    group = conceal,
+    pattern = { "*" },
+    callback = function(args)
+      -- `:h FileType` and `:h nvim_create_augroup`.
+      -- `amatch`: value of filetype; args.match <- amatch
+      local ft = args.match
+      local group = group_map[ft]
+      if group == nil then
+        return
+      end
+      group_handler[group](ft, group)
+    end
+  })
+  vim.api.nvim_create_autocmd({ "ModeChanged" }, {
+    group = conceal,
+    pattern = "?:?",
+    callback = function()
+      local new_mode = vim.fn.mode("1")
+      local level = conceal_by_mode[new_mode]
+      if level then
+        vim.opt_local.conceallevel = level
+      end
+    end
+  })
+end -- }}}
+
 vim.api.nvim_create_user_command('Dark', function(opts)
     -- opts: {name, args: str, fargs: Splited<str>, range, ...}
     ---@type string
@@ -307,8 +380,9 @@ require('trouble').setup {
 }
 
 
--- TODO: Any way to collect all the TODOs and its variants?
-require('todo-comments').setup()
+-- TODO + Trouble: `:TodoTrouble`
+require('todo-comments').setup {}
+
 
 -- plugin keymaps
 
@@ -320,11 +394,12 @@ end
 -- Comment.nvim
 require('Comment').setup()
 -- -- lukas-reineke/indent-blankline.nvim
--- vim.opt.list = true
--- vim.opt.listchars:append "space:⋅"
--- vim.opt.listchars:append "eol:↴"
+vim.opt.list = true
+vim.opt.listchars:append "space:⋅"
+vim.opt.listchars:append "eol:↴"
 
 require("ibl").setup {
+  -- indent = {char = {space='', eol=''}, },
   -- show_end_of_line = true,
   -- space_char_blankline = " ",
 
@@ -439,7 +514,6 @@ stdout> (builtin.__file)
 
   log.debug(vim.inspect(filenames))
 
-
   for _, filename in pairs(filenames) do
     require('harpoon.mark').add_file(filename)
   end
@@ -1437,15 +1511,17 @@ require('lualine').setup {
         newfile_status = false,
         path = 1,
         symbols = {
-          modified = '[+]',
+          modified = '[~]',
           readonly = '[-]',
-          unnamed = '[Unnamed]',
-          newfile = '[New]',
+          unnamed = '<?>',
         },
       },
     },
-    lualine_x = { 'encoding', 'fileformat', 'filetype', },
-    lualine_y = { 'progress' },
+    lualine_x = { 'encoding', 'fileformat', {
+      'filetype',
+      colored = true,
+    }, },
+    lualine_y = { function() return "pid#" .. vim.loop.os_getpid() end },
     lualine_z = { 'location' },
   },
   inactive_sections = {
diff --git a/nix/dotfiles/devshells.nix b/nix/dotfiles/devshells.nix
index 177c8be..04eca87 100644
--- a/nix/dotfiles/devshells.nix
+++ b/nix/dotfiles/devshells.nix
@@ -6,6 +6,8 @@
 in {
   default = std.lib.dev.mkShell {
     name = "default";
-    imports = [inputs.std.std.devshellProfiles.default];
+    imports = [
+      inputs.std.std.devshellProfiles.default
+    ];
   };
 }
diff --git a/nix/repo/home-configs/default.nix b/nix/repo/home-configs/default.nix
index e8e1f5b..d899f74 100644
--- a/nix/repo/home-configs/default.nix
+++ b/nix/repo/home-configs/default.nix
@@ -30,6 +30,11 @@
     {config.programs.home-manager.enable = true;}
     # home-profiles.nix-index
     home-profiles.neovim
+    {
+      config.repo.shells.shellAliases = {
+        nixr = "if [ -f $(pwd)/.nix-replrc ]; then nix repl $(pwd)/.nix-replrc; elif [ -f ~/.config/.nix-replrc ]; then nix repl ~/.config/.nix-replrc; else nix repl; fi";
+      };
+    }
   ];
 in {
   homeConfigurations.htran = home-config {
diff --git a/nix/repo/home-modules/default.nix b/nix/repo/home-modules/default.nix
index 40aa4f7..aae1001 100644
--- a/nix/repo/home-modules/default.nix
+++ b/nix/repo/home-modules/default.nix
@@ -8,12 +8,7 @@ _imports @ {
   namespace = "repo";
   imports = _imports // {inherit namespace;};
 in {
-  git = {
-    config,
-    lib,
-    options,
-    ...
-  }: let
+  git = { config, lib, options, ... }: let
     cfg = config."${namespace}".git;
     baseAliases = {
       a = "add";
diff --git a/nix/repo/home-profiles/neovim.nix b/nix/repo/home-profiles/neovim.nix
index 7006587..04a7833 100644
--- a/nix/repo/home-profiles/neovim.nix
+++ b/nix/repo/home-profiles/neovim.nix
@@ -96,6 +96,7 @@ in {
       * }
       */
       plugins = let
+        inherit (cell.lib.deprecate) mkDeprecate deprecate-seq-handler;
         inherit
           (inputs.nixpkgs-vimplugins.legacyPackages.${system}.vimPlugins)
           plenary-nvim
@@ -144,63 +145,75 @@ in {
           nvim-colorizer-lua
           git-worktree-nvim
           ;
-        # inherit (inputs.cells.dotfiles.packages) sg-nvim;
-      in [
-        plenary-nvim
-        nvim-treesitter.withAllGrammars
-        nvim-treesitter-textobjects
-        telescope-fzf-native-nvim
-        telescope-file-browser-nvim
-        telescope-nvim
-        nvim-lspconfig
-        gruvbox-community
-        neodev-nvim
-        cmp-nvim-lsp
-        cmp-path
-        cmp-buffer
-        cmp-cmdline
-        nvim-cmp
-        lspkind-nvim
-        nvim-autopairs
-        nvim-ts-autotag
-        guess-indent-nvim
-        harpoon
-        luasnip
-        nvim-treesitter-context
-        fidget-nvim
-        rust-tools-nvim
-        telescope-live-grep-args-nvim
-        comment-nvim
+        sg-nvim = let
+          _sg = inputs.cells.dotfiles.packages.sg-nvim;
+        in {
+          plugin = _sg;
+          # NOTE: Wait, this mean the plugin is exclusively lua only since package.cpath is Lua API
+          config = ''
+            package.cpath = package.cpath .. ";${_sg}/lib/*.so;${_sg}/lib/*.dylib"
+          '';
+          type = "lua";
+        };
+      in
+        deprecate-seq-handler 1 [
+          (mkDeprecate {inherit sg-nvim;} {
+            stage = 2;
+            meta.since = "2023-10-20";
+          })
+          (mkDeprecate {inherit vim-jack-in;} {
+            stage = 2;
+            meta.since = "2023-10-20";
+          })
+          plenary-nvim
+          nvim-treesitter.withAllGrammars
+          nvim-treesitter-textobjects
+          telescope-fzf-native-nvim
+          telescope-file-browser-nvim
+          telescope-nvim
+          nvim-lspconfig
+          gruvbox-community
+          neodev-nvim
+          cmp-nvim-lsp
+          cmp-path
+          cmp-buffer
+          cmp-cmdline
+          nvim-cmp
+          lspkind-nvim
+          nvim-autopairs
+          nvim-ts-autotag
+          guess-indent-nvim
+          harpoon
+          luasnip
+          nvim-treesitter-context
+          fidget-nvim
+          rust-tools-nvim
+          telescope-live-grep-args-nvim
+          comment-nvim
 
-        cmp_luasnip
-        gitsigns-nvim
-        indent-blankline-nvim
-        lualine-nvim
-        mason-lspconfig-nvim
-        mason-nvim
-        neogit
-        nvim-jqx
-        nvim-surround
-        nvim-web-devicons
-        playground
-        todo-comments-nvim
-        trouble-nvim
-        vim-dispatch
-        vim-dispatch-neovim
-        vim-fugitive
-        nvim-colorizer-lua
-        vim-jack-in
-        # {
-        #   plugin = sg-nvim;
-        #   # NOTE: Wait, this mean the plugin is exclusively lua only since package.cpath is Lua API
-        #   config = ''
-        #     package.cpath = package.cpath .. ";${sg-nvim}/lib/*.so;${sg-nvim}/lib/*.dylib"
-        #   '';
-        #   type = "lua";
-        # }
-        git-worktree-nvim
-        nui-nvim
-      ];
+          cmp_luasnip
+          gitsigns-nvim
+          indent-blankline-nvim
+          lualine-nvim
+          mason-lspconfig-nvim
+          mason-nvim
+          neogit
+          nvim-jqx
+          nvim-surround
+          nvim-web-devicons
+          playground
+          todo-comments-nvim
+          trouble-nvim
+          vim-dispatch
+          vim-dispatch-neovim
+          vim-fugitive
+          nvim-colorizer-lua
+          git-worktree-nvim
+          (mkDeprecate {inherit nui-nvim;} {
+            stage = 2;
+            meta.since = "2023-10-20";
+          })
+        ];
     };
     # home.packages = nvim_pkgs;
   };
diff --git a/nix/repo/lib/default.nix b/nix/repo/lib/default.nix
index d32f332..777101e 100644
--- a/nix/repo/lib/default.nix
+++ b/nix/repo/lib/default.nix
@@ -1,9 +1,7 @@
-{
+std-passthru @ {
   inputs,
   cell,
 }: let
-  namespace = "repo"; # ignore: unused
-
   yamlToJsonDrv = pkgs: yamlContent: outputPath: (pkgs.runCommand
     outputPath
     {
@@ -15,6 +13,18 @@
     ''
       echo "$yamlContent" | yq >$out
     '');
+
+  exec_tests = testUnit: let
+    testNames = builtins.attrNames testUnit;
+    evaluateTest = testName: assert testUnit."${testName}" == true; testName;
+  in
+    builtins.concatStringsSep ", " (builtins.foldl' (acc: testName: acc ++ [(evaluateTest testName)]) [] testNames);
+  tests = import ./tests.nix std-passthru;
 in {
   fromYAML = yamlContent: builtins.fromJSON (builtins.readFile (yamlToJsonDrv inputs.nixpkgs yamlContent "fromYaml.json"));
+  ty = import ./ty.nix std-passthru;
+  deprecate = import ./mk-deprecate.nix std-passthru;
+
+  inherit tests;
+  exec-tests = exec_tests tests;
 }
diff --git a/nix/repo/lib/effects.nix b/nix/repo/lib/effects.nix
new file mode 100644
index 0000000..78b03ed
--- /dev/null
+++ b/nix/repo/lib/effects.nix
@@ -0,0 +1,2 @@
+{inputs, cell}: {
+}
diff --git a/nix/repo/lib/mk-deprecate.nix b/nix/repo/lib/mk-deprecate.nix
new file mode 100644
index 0000000..44632e3
--- /dev/null
+++ b/nix/repo/lib/mk-deprecate.nix
@@ -0,0 +1,52 @@
+{
+  inputs,
+  cell,
+}: let
+  inherit (cell.lib.ty) brand-ctor brand-coalesce-seq unbranded_name;
+
+  deprecate_t = a @ {
+    id ? null,
+    msg ? null,
+    ctx_str ? null,
+    meta ? null,
+    /*
+    the higher the more likely to be removed
+    */
+    stage ? 0,
+  }: let
+    ctx =
+      if ctx_str == null
+      then ""
+      else ": ${ctx_str}";
+    _msg =
+      if msg == null
+      then
+        if id == null
+        then "deprecated${ctx}"
+        else "${id} is deprecated${ctx}"
+      else msg;
+  in
+    builtins.trace _msg (v: (brand-ctor "deprecate" v) // {inherit stage;} // a);
+in {
+  inherit deprecate_t;
+  mkDeprecate = inherit_v: a: deprecate_t ({id = builtins.head (builtins.attrNames inherit_v);} // a) (builtins.head (builtins.attrValues inherit_v));
+  deprecate-seq-handler = trim_stage: s: let
+    v = builtins.foldl' (lst: {
+        __value,
+        __brand,
+        ...
+      } @ a:
+        if __brand == "deprecate" && trim_stage < a.stage
+        then lst
+        else
+          lst
+          ++ [
+            (
+              if __brand == "deprecate" || __brand == unbranded_name
+              then __value
+              else a
+            )
+          ]) [] (brand-coalesce-seq s);
+  in
+    v;
+}
diff --git a/nix/repo/lib/tests.nix b/nix/repo/lib/tests.nix
new file mode 100644
index 0000000..0903536
--- /dev/null
+++ b/nix/repo/lib/tests.nix
@@ -0,0 +1,89 @@
+{
+  inputs,
+  cell,
+}: {
+  ty-deprecate = let
+    exampleBrand = cell.lib.ty.brand-ctor "example";
+    brandedItem = exampleBrand "someValue";
+  in
+    assert (brandedItem.__brand == "example");
+    assert (brandedItem.__value == "someValue"); let
+      coalescedItem = cell.lib.ty.brand-coalesce brandedItem;
+      coalescedSeq = cell.lib.ty.brand-coalesce-seq [brandedItem "hello"];
+      promoted = cell.lib.ty.brand-coalesce "hello";
+    in
+      assert (coalescedItem.__brand != "__unbranded__");
+      assert (promoted.__brand == "__unbranded__");
+      assert ((builtins.elemAt coalescedSeq 0) == brandedItem);
+      assert ((let v = builtins.elemAt coalescedSeq 1; in builtins.trace "${builtins.toJSON v}" v) == promoted); let
+        items = [(exampleBrand "A") (exampleBrand "B") (cell.lib.ty.brand-ctor "second" "C")];
+        grouped = cell.lib.ty.brand-group items;
+      in
+        assert (builtins.length (grouped.example) == 2);
+        assert (builtins.length (grouped.second) == 1); let
+          retainItem = cell.lib.deprecate.mkDeprecate {myItem = "value";} {ctx_str = "example context";};
+          deprecate = cell.lib.deprecate.mkDeprecate {deprecate = 15;} {stage = 256;};
+          processedSeq = cell.lib.deprecate.deprecate-seq-handler 0 [retainItem];
+          partiallyRemoved = cell.lib.deprecate.deprecate-seq-handler 2 [retainItem brandedItem];
+          removeDeprecated = cell.lib.deprecate.deprecate-seq-handler 2 [deprecate brandedItem];
+          passthru = cell.lib.deprecate.deprecate-seq-handler 4 [retainItem brandedItem deprecate];
+        in
+          assert (retainItem.__brand == "deprecate");
+          # Since the stage is 0, it filters the deprecated item out
+          assert (builtins.length processedSeq == 1);
+          assert (builtins.head partiallyRemoved == "value");
+          assert (builtins.head removeDeprecated == brandedItem);
+          assert (builtins.length passthru == 2); true;
+  deprecate = let
+    inherit (cell.lib.deprecate) mkDeprecate deprecate-seq-handler;
+    inherit (inputs.nixpkgs) system;
+    inherit
+      (inputs.nixpkgs-vimplugins.legacyPackages.${system}.vimPlugins)
+      plenary-nvim
+      nvim-treesitter
+      nvim-treesitter-textobjects
+      nvim-treesitter-context
+      telescope-fzf-native-nvim
+      telescope-file-browser-nvim
+      vim-jack-in
+      nui-nvim
+      telescope-live-grep-args-nvim
+      nvim-colorizer-lua
+      git-worktree-nvim
+      ;
+    sg-nvim = let
+      _sg = inputs.cells.dotfiles.packages.sg-nvim;
+    in {
+      plugin = _sg;
+      # NOTE: Wait, this mean the plugin is exclusively lua only since package.cpath is Lua API
+      config = ''
+        package.cpath = package.cpath .. ";${_sg}/lib/*.so;${_sg}/lib/*.dylib"
+      '';
+      type = "lua";
+    };
+    plugins = [
+      (mkDeprecate {inherit sg-nvim;} {
+        stage = 2;
+        meta.since = "2023-10-20";
+      })
+      (mkDeprecate {inherit vim-jack-in;} {
+        stage = 2;
+        meta.since = "2023-10-20";
+      })
+      plenary-nvim
+      nvim-treesitter.withAllGrammars
+      nvim-treesitter-textobjects
+      telescope-fzf-native-nvim
+      telescope-file-browser-nvim
+      nvim-treesitter-context
+      telescope-live-grep-args-nvim
+      nvim-colorizer-lua
+      git-worktree-nvim
+      nui-nvim
+    ];
+    pluglen = builtins.length plugins;
+    rm = let v = deprecate-seq-handler 1 plugins; in assert (builtins.length v) < pluglen; v;
+    retain = let v = deprecate-seq-handler 10 plugins; in assert (builtins.length v) == pluglen; v;
+  in
+    builtins.trace (builtins.toJSON {inherit rm retain;}) true;
+}
diff --git a/nix/repo/lib/ty.nix b/nix/repo/lib/ty.nix
new file mode 100644
index 0000000..b548f86
--- /dev/null
+++ b/nix/repo/lib/ty.nix
@@ -0,0 +1,23 @@
+{
+  inputs,
+  cell,
+}: let
+  brand-ctor = name:
+    assert builtins.isString name;
+      v: {
+        __brand = name;
+        __value = v;
+      };
+  unbranded_name = "__unbranded__";
+  unbranded_t = brand-ctor unbranded_name;
+  brand-of = {
+    __brand ? unbranded_name,
+    __value ? null,
+  }:
+    __brand;
+  brand-coalesce = v: if v ? __brand then v else unbranded_t v;
+in {
+  inherit brand-ctor brand-of brand-coalesce unbranded_name;
+  brand-group = seq: builtins.mapAttrs (_: builtins.map (v: v.__value)) (builtins.groupBy (brnd: brnd.__brand) seq);
+  brand-coalesce-seq = builtins.map brand-coalesce;
+}