Add python snippets.

users/jrpotter/lang/python.nix

@@ -19,6 +19,10 @@
     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 = ''

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

@@ -0,0 +1,16 @@
+local s = require('luasnip').snippet
+local i = require('luasnip').insert_node
+local fmt = require('luasnip.extras.fmt').fmt
+
+local v = require('utils.snippets').visual_dynamic_node
+
+return {
+  s(
+    { name = 'for', trig = 'for' },
+    fmt([[
+for {} in {}:
+  {}]],
+      { i(1, ''), i(2, ''), v(3) }
+    )
+  ),
+}

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

@@ -0,0 +1,28 @@
+local M = {}
+
+local luasnip = require('luasnip')
+local d = luasnip.dynamic_node
+local i = luasnip.insert_node
+local sn = luasnip.snippet_node
+
+-- Creates an insertion node with a default value of whatever was stored in the
+-- visual selection prior to entering insert mode (refer to the configuration
+-- field `store_selection_keys`).
+function M.visual_dynamic_node(index, default)
+  return d(index, function(_, parent)
+    local res, env = {}, parent.snippet.env
+    if type(env.LS_SELECT_RAW) ~= 'table' then
+      return sn(nil, { i(1, default or '') }, '')
+    end
+    for k, v in ipairs(env.LS_SELECT_RAW) do
+      local indent = env.CUSTOM_POS[2] - 1
+      table.insert(res, (k == 1 and v) or string.rep(' ', indent) .. v)
+    end
+    if table.concat(res):match('^%s*$') then
+      return sn(nil, { i(1, default or '') }, '')
+    end
+    return sn(nil, { i(1, res) }, '')
+  end, {})
+end
+
+return M

users/jrpotter/neovim/default.nix

@@ -27,6 +27,13 @@ let
     '';
   };
 
+  luasnip = {
+    plugin = pkgs.vimPlugins.luasnip;
+    config = ''
+      ${config.programs.neovim.nvim-snippets}
+    '';
+  };
+
   nvim-cmp = {
     plugin = pkgs.vimPlugins.nvim-cmp;
     config = ''
@@ -97,6 +104,16 @@ 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 +130,7 @@ in
         } else p) [
         colorscheme  # Is always first.
         lualine
+        luasnip
         nvim-cmp
         nvim-dap
         nvim-lspconfig
@@ -121,7 +139,6 @@ 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
       ];