nixbook: add postman, gofmt, difftastic

lib/mkconf.nix

@@ -24,6 +24,7 @@ in
           home-manager = {
             useGlobalPkgs = true;
             useUserPackages = true;
+            backupFileExtension = "bak";
             users.${user}.imports =
               home-modules
               ++ [

lib/nixvim.nix

@@ -66,6 +66,14 @@
       key = "<C-S-Tab>";
       action = "<CMD>tabprev<CR>";
     }
+    {
+      key = "<leader>bn";
+      action = "<CMD>bnext<CR>";
+    }
+    {
+      key = "<leader>bp";
+      action = "<CMD>bprevious<CR>";
+    }
     {
       key = "gl";
       action = "g$";
@@ -155,6 +163,33 @@
     }
   ];
 
+  autoCmd = [{
+    event = "BufWritePre";
+    pattern = "*.go";
+    # https://github.com/golang/tools/blob/master/gopls/doc/vim.md#imports-and-formatting
+    callback.__raw = ''
+    function()
+      local params = vim.lsp.util.make_range_params()
+      params.context = {only = {"source.organizeImports"}}
+      -- buf_request_sync defaults to a 1000ms timeout. Depending on your
+      -- machine and codebase, you may want longer. Add an additional
+      -- argument after params if you find that you have to write the file
+      -- twice for changes to be saved.
+      -- E.g., vim.lsp.buf_request_sync(0, "textDocument/codeAction", params, 3000)
+      local result = vim.lsp.buf_request_sync(0, "textDocument/codeAction", params)
+      for cid, res in pairs(result or {}) do
+        for _, r in pairs(res.result or {}) do
+          if r.edit then
+            local enc = (vim.lsp.get_client_by_id(cid) or {}).offset_encoding or "utf-16"
+            vim.lsp.util.apply_workspace_edit(r.edit, enc)
+          end
+        end
+      end
+      vim.lsp.buf.format({async = false})
+    end
+    '';
+  }];
+
   plugins = {
     bufferline.enable = true;
     web-devicons.enable = true;
@@ -188,6 +223,7 @@
       servers = {
         ts-ls.enable = true;
         nil-ls.enable = true;
+        yamlls.enable = true;
         gopls.enable = true;
       };
       keymaps = {