Maintain `<c-e>` and `<c-y>` functionality in insert/select mode.

users/jrpotter/default.nix

@@ -8,7 +8,7 @@ in
     ./bash
     ./git.nix
     ./lang/bash.nix
-    ./lang/c.nix
+    ./lang/cxx.nix
     ./lang/elixir.nix
     ./lang/lean.nix
     ./lang/lua.nix

users/jrpotter/lang/bash.nix

@@ -7,7 +7,7 @@
 
   programs.neovim = {
     nvim-lspconfig = ''
-      require('init.lsp').setup(require('lspconfig').bashls) {}
+      require('utils.lsp').setup(require('lspconfig').bashls) {}
     '';
   };
 }

users/jrpotter/lang/cxx.nix

@@ -15,11 +15,11 @@ in
 
   programs.neovim = {
     nvim-dap = ''
-      require('init.c').nvim_dap()
+      require('cxx.init').nvim_dap()
     '';
 
     nvim-lspconfig = ''
-      require('init.c').nvim_lspconfig()
+      require('cxx.init').nvim_lspconfig()
 
       vim.filetype.add({
         pattern = {
@@ -30,6 +30,6 @@ in
   };
 
   xdg.configFile."nvim/after/ftplugin/c.lua".text = ''
-    require('init.dap').buffer_map()
+    require('utils.dap').buffer_map()
   '';
 }

users/jrpotter/lang/elixir.nix

@@ -6,7 +6,7 @@
 
   programs.neovim = {
     nvim-lspconfig = ''
-      require('init.lsp').setup(require('lspconfig').elixirls) {
+      require('utils.lsp').setup(require('lspconfig').elixirls) {
         cmd = { 'elixir-ls' },
       }
     '';

users/jrpotter/lang/lean.nix

@@ -8,7 +8,7 @@ let
       "Julian/lean.nvim";
     config = ''
       lua << EOF
-      require('init.lsp').setup(require('lean')) {
+      require('utils.lsp').setup(require('lean')) {
         abbreviations = { builtin = true },
         mappings = true,
       }

users/jrpotter/lang/lua.nix

@@ -6,7 +6,7 @@
 
   programs.neovim = {
     nvim-lspconfig = ''
-      require('init.lua').nvim_lspconfig()
+      require('lua.init').nvim_lspconfig()
     '';
   };
 }

users/jrpotter/lang/markdown.nix

@@ -6,7 +6,7 @@
 
   programs.neovim = {
     nvim-lspconfig = ''
-      require('init.lsp').setup(require('lspconfig').marksman) {}
+      require('utils.lsp').setup(require('lspconfig').marksman) {}
     '';
   };
 }

users/jrpotter/lang/nix.nix

@@ -6,7 +6,7 @@
 
   programs.neovim = {
     nvim-lspconfig = ''
-      require('init.lsp').setup(require('lspconfig').nil_ls) {}
+      require('utils.lsp').setup(require('lspconfig').nil_ls) {}
     '';
   };
 }

users/jrpotter/lang/python.nix

@@ -13,15 +13,19 @@
 
   programs.neovim = {
     nvim-dap = ''
-      require('init.python').nvim_dap()
+      require('python.init').nvim_dap()
     '';
 
     nvim-lspconfig = ''
-      require('init.python').nvim_lspconfig()
+      require('python.init').nvim_lspconfig()
+    '';
+
+    nvim-snippets = ''
+      require('luasnip').add_snippets('python', require('python.snippets'))
     '';
   };
 
   xdg.configFile."nvim/after/ftplugin/python.lua".text = ''
-    require('init.dap').buffer_map()
+    require('utils.dap').buffer_map()
   '';
 }

users/jrpotter/lang/typescript.nix

@@ -7,9 +7,9 @@
 
   programs.neovim = {
     nvim-lspconfig = ''
-      require('init.lsp').setup(require('lspconfig').tsserver) {
+      require('utils.lsp').setup(require('lspconfig').tsserver) {
         on_attach = function(client, bufnr)
-          require('init.lsp').on_attach(client, bufnr)
+          require('utils.lsp').on_attach(client, bufnr)
           -- Override the default formatter in typescript-language-server.
           vim.api.nvim_buf_set_keymap(bufnr, 'n', 'gq', "<CMD>PrettierAsync<CR>", {
             silent = true,

users/jrpotter/neovim/config/cxx/init.lua

@@ -31,7 +31,7 @@ function M.nvim_dap()
 end
 
 function M.nvim_lspconfig()
-  require('init.lsp').setup(require('lspconfig').clangd) {}
+  require('utils.lsp').setup(require('lspconfig').clangd) {}
 end
 
 return M

users/jrpotter/neovim/config/lua/init.lua

@@ -1,7 +1,7 @@
 local M = {}
 
 function M.nvim_lspconfig()
-  require('init.lsp').setup(require('lspconfig').lua_ls) {
+  require('utils.lsp').setup(require('lspconfig').lua_ls) {
     -- Provide completions, analysis, and location handling for plugins on the
     -- vim runtime path.
     -- https://github.com/neovim/nvim-lspconfig/blob/48347089666d5b77d054088aa72e4e0b58026e6e/doc/server_configurations.md#lua_ls

users/jrpotter/neovim/config/python/init.lua

@@ -24,7 +24,7 @@ function M.nvim_dap()
 end
 
 function M.nvim_lspconfig()
-  require('init.lsp').setup(require('lspconfig').pylsp) {
+  require('utils.lsp').setup(require('lspconfig').pylsp) {
     settings = {
       pylsp = {
         -- `flake8` currently fails in some cases. Prefer the default set of

users/jrpotter/neovim/config/python/snippets.lua

@@ -0,0 +1,58 @@
+local c = require('luasnip').choice_node
+local d = require('luasnip').dynamic_node
+local i = require('luasnip').insert_node
+local sn = require('luasnip').snippet_node
+local t = require('luasnip').text_node
+
+local s = require('luasnip').snippet
+local fmt = require('luasnip.extras.fmt').fmt
+
+local VISUAL = require('utils.luasnip').VISUAL
+
+return {
+  s(
+    { name = 'for', trig = 'for' },
+    fmt([[
+for {} in {}:
+    {}]],
+      {
+        c(1, {
+          i(1, 'i'),
+          i(2, 'k'),
+          i(3, 'v'),
+          sn(4, { i(1, 'k'), t(', '), i(2, 'v') }),
+        }),
+        d(2, function(args, _, old_state)
+          local default = i(nil, 'val')
+          local snip = old_state or default
+
+          if args[1][1] == 'i' then
+            snip = sn(nil, c(1, {
+              { t('range('), i(1, 'n'), t(')') },
+              default,
+            }))
+          elseif args[1][1] == 'k' then
+            snip = sn(nil, c(1, {
+              { i(1, 'dict'), t('.keys()') },
+              default,
+            }))
+          elseif args[1][1] == 'v' then
+            snip = sn(nil, c(1, {
+              { i(1, 'dict'), t('.values()') },
+              default,
+            }))
+          elseif args[1][1] == 'k, v' then
+            snip = sn(nil, c(1, {
+              { i(1, 'dict'), t('.items()') },
+              default,
+            }))
+          end
+
+          snip.old_state = snip
+          return snip
+        end, { 1 }),
+        VISUAL,
+      }
+    )
+  ),
+}

users/jrpotter/neovim/config/utils/cmp.lua

@@ -2,7 +2,7 @@ local M = {}
 
 local cmp = require('cmp')
 local cmp_buffer = require('cmp_buffer')
-local luasnip = require("luasnip")
+local luasnip = require('luasnip')
 
 function M.setup()
   cmp.setup {
@@ -12,9 +12,8 @@ function M.setup()
       end,
     },
     sources = {
-      {
-        name = 'nvim_lsp',
-      },
+      { name = 'luasnip' },
+      { name = 'nvim_lsp' },
       {
         name = 'buffer',
         option = {
@@ -31,29 +30,24 @@ function M.setup()
     },
     sorting = {
       comparators = {
-        function (...)
-          -- This also sorts completion results coming from other sources (e.g.
-          -- LSPs).
+        function(...)
+          -- This also sorts completion results coming from other sources.
           return cmp_buffer:compare_locality(...)
         end,
       },
     },
     mapping = {
-      ['<c-n>'] = cmp.mapping(function(fallback)
-        if cmp.visible() then cmp.select_next_item() else fallback() end
-      end, { 'i', 's' }),
-
-      ['<c-p>'] = cmp.mapping(function(fallback)
-        if cmp.visible() then cmp.select_prev_item() else fallback() end
+      ['<tab>'] = cmp.mapping(function(fallback)
+        if cmp.get_active_entry() then cmp.confirm() else fallback() end
       end, { 'i', 's' }),
 
       ['<c-l>'] = cmp.mapping(function(fallback)
         if cmp.visible() then cmp.abort() else fallback() end
       end, { 'i', 's' }),
 
-      ['<tab>'] = cmp.mapping(function(fallback)
-        if cmp.get_active_entry() then
-          cmp.confirm()
+      ['<c-n>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then
+          cmp.select_next_item()
         elseif luasnip.expand_or_locally_jumpable() then
           luasnip.expand_or_jump()
         else
@@ -61,8 +55,10 @@ function M.setup()
         end
       end, { 'i', 's' }),
 
-      ['<s-tab>'] = cmp.mapping(function(fallback)
-        if luasnip.jumpable(-1) then
+      ['<c-p>'] = cmp.mapping(function(fallback)
+        if cmp.visible() then
+          cmp.select_prev_item()
+        elseif luasnip.locally_jumpable(-1) then
           luasnip.jump(-1)
         else
           fallback()

users/jrpotter/neovim/config/utils/luasnip.lua

@@ -0,0 +1,60 @@
+local M = {}
+
+local luasnip = require('luasnip')
+local types = require('luasnip.util.types')
+local f = require('luasnip').function_node
+
+M.VISUAL = f(function(_, snip)
+  local res, env = {}, snip.env
+  for _, ele in ipairs(env.LS_SELECT_RAW) do
+    table.insert(res, ele)
+  end
+  return res
+end, {})
+
+function M.setup()
+  luasnip.config.setup {
+    region_check_events = 'InsertEnter',
+    delete_check_events = 'InsertLeave',
+    store_selection_keys = '<tab>',
+    ext_opts = {
+      [types.snippet] = {
+        active = {
+          virt_text = { { '●', 'DiagnosticWarn' } },
+        },
+      },
+      [types.choiceNode] = {
+        active = {
+          virt_text = { { '⧨', 'DiagnosticHint' } },
+          -- Include in case one of our choice options is an empty string.
+          hl_group = 'DiagnosticOk',
+        },
+      },
+    },
+  }
+
+  vim.keymap.set({ 'i', 's' }, '<c-e>', function()
+    if luasnip.choice_active() then
+      return '<Plug>luasnip-next-choice'
+    else
+      return '<c-e>'
+    end
+  end, { silent = true, expr = true, remap = true })
+
+  vim.keymap.set({ 'i', 's' }, '<c-y>', function()
+    if luasnip.choice_active() then
+      return '<Plug>luasnip-prev-choice'
+    else
+      return '<c-y>'
+    end
+  end, { silent = true, expr = true, remap = true })
+
+  -- Allow aborting the active snippet at any point in time.
+  vim.keymap.set(
+    { 'n', 'i', 's' },
+    '<c-l>',
+    '<cmd>LuaSnipUnlinkCurrent<cr>'
+  )
+end
+
+return M

users/jrpotter/neovim/default.nix

@@ -18,8 +18,8 @@ let
         sections = {
           lualine_x = {'encoding', 'filetype'},
           lualine_y = {
-            require('init.statusline').get_active_lsp,
-            require('init.statusline').get_dap_status,
+            require('utils.statusline').get_active_lsp,
+            require('utils.statusline').get_dap_status,
           },
           lualine_z = {'%c:%l:%%%p'},
         },
@@ -27,10 +27,18 @@ let
     '';
   };
 
+  luasnip = {
+    plugin = pkgs.vimPlugins.luasnip;
+    config = ''
+      require('utils.luasnip').setup()
+      ${config.programs.neovim.nvim-snippets}
+    '';
+  };
+
   nvim-cmp = {
     plugin = pkgs.vimPlugins.nvim-cmp;
     config = ''
-      require('init.cmp').setup()
+      require('utils.cmp').setup()
     '';
   };
 
@@ -52,7 +60,7 @@ let
   nvim-telescope = {
     plugin = pkgs.vimPlugins.telescope-nvim;
     config = ''
-      require('init.telescope').setup()
+      require('utils.telescope').setup()
     '';
   };
 
@@ -72,7 +80,7 @@ let
       ]
     ));
     config = ''
-      require('init.treesitter').setup()
+      require('utils.treesitter').setup()
     '';
   };
 in
@@ -97,6 +105,16 @@ in
         Language-specific configurations for the `nvim-lspconfig` plugin.
       '';
     };
+
+    nvim-snippets = lib.mkOption {
+      type = lib.types.lines;
+      example = ''
+        require('...').nvim_lspconfig()
+      '';
+      description = lib.mdDoc ''
+        Language-specific configurations for the `luasnip` plugin.
+      '';
+    };
   };
 
   config = {
@@ -113,6 +131,7 @@ in
         } else p) [
         colorscheme  # Is always first.
         lualine
+        luasnip
         nvim-cmp
         nvim-dap
         nvim-lspconfig
@@ -121,7 +140,6 @@ in
         pkgs.vimPlugins.cmp-buffer
         pkgs.vimPlugins.cmp-nvim-lsp
         pkgs.vimPlugins.cmp_luasnip
-        pkgs.vimPlugins.luasnip
         pkgs.vimPlugins.nvim-web-devicons
         pkgs.vimPlugins.vim-prettier
       ];
@@ -131,13 +149,13 @@ in
 
     xdg.configFile."nvim/init.lua".text =
       let
-        lua = import ./lua { inherit pkgs; };
+        config = import ./config { inherit pkgs; };
       in
         lib.mkMerge [
           # Extra Lua configuration to be prepended to `init.lua`. Extend the
           # Lua loader to search for our /nix/store/.../?.lua files.
           (lib.mkBefore ''
-            package.path = '${lua}/?.lua;' .. package.path
+            package.path = '${config}/?.lua;' .. package.path
           '')
           # Extra Lua configuration to be appended to `init.lua`.
           (lib.mkAfter ''