Improve the usability of rust-dbg-wrap-or-unwrap (#498)

* rust-dbg-wrap-or-unwrap: Cut unnecessary conditional branches for region-active-p

* rust-dbg-wrap-or-unwrap: Do not using save-excursion anymore

* rust-dbg-wrap-or-unwrap: Use cond, allow more other cases.

* rust-dbg-wrap-or-unwrap: Introduce rust-insert-dbg-alone

* rust-dbg-wrap-or-unwrap: Adjust cursor position after insertion

* rust-dbg-wrap-or-unwrap: Add tests for empty line

* rust-dbg-wrap-or-unwrap: Test final position in empty line case

* rust-dbg-wrap-or-unwrap: Test final cursor position in existing wrap tests

rust-mode-tests.el

@@ -45,14 +45,16 @@
 (put 'rust-compare-code-after-manip 'ert-explainer
      'rust-test-explain-bad-manip)
 
-(defun rust-test-manip-code (original point-pos manip-func expected)
+(defun rust-test-manip-code (original manip-pos manip-func expected &optional final-pos)
   (with-temp-buffer
     (rust-mode)
     (insert original)
-    (goto-char point-pos)
+    (goto-char manip-pos)
     (funcall manip-func)
     (should (rust-compare-code-after-manip
-             original point-pos manip-func expected (buffer-string)))))
+             original manip-pos manip-func expected (buffer-string)))
+    (if final-pos
+        (should (equal (point) final-pos)))))
 
 (defmacro rust-test-with-standard-fill-settings (&rest body)
   (declare (indent defun))
@@ -3452,14 +3454,49 @@ impl Two<'a> {
    "let x = add(first, second);"
    15
    #'rust-dbg-wrap-or-unwrap
-   "let x = add(dbg!(first), second);"))
+   "let x = add(dbg!(first), second);"
+   24))
+
+(ert-deftest rust-test-dbg-wrap-empty-line ()
+  (rust-test-manip-code
+   "let a = 1;
+
+let b = 1;"
+   12
+   #'rust-dbg-wrap-or-unwrap
+   "let a = 1;
+dbg!()
+let b = 1;"
+   17))
+
+(ert-deftest rust-test-dbg-wrap-empty-before-comment ()
+  (rust-test-manip-code
+   "let a = 1;
+// comment
+let b = 1;"
+   12
+   #'rust-dbg-wrap-or-unwrap
+   "let a = 1;
+dbg!()// comment
+let b = 1;"
+   17)
+  ;; between statements and comments
+  (rust-test-manip-code
+   "let a = 1;// comment
+let b = 1;"
+   11
+   #'rust-dbg-wrap-or-unwrap
+   "let a = 1;dbg!()// comment
+let b = 1;"
+   16))
 
 (ert-deftest rust-test-dbg-wrap-symbol-unbalanced ()
   (rust-test-manip-code
    "let x = add((first, second);"
    14
    #'rust-dbg-wrap-or-unwrap
-   "let x = add((dbg!(first), second);"))
+   "let x = add((dbg!(first), second);"
+   25))
 
 (ert-deftest rust-test-dbg-wrap-region ()
   (rust-test-manip-code
@@ -3470,7 +3507,8 @@ impl Two<'a> {
      (push-mark nil t t)
      (goto-char 26)
      (rust-dbg-wrap-or-unwrap))
-   "let x = dbg!(add(first, second));"))
+   "let x = dbg!(add(first, second));"
+   33))
 
 (defun rust-test-dbg-unwrap (position)
   (rust-test-manip-code

rust-utils.el

@@ -37,45 +37,65 @@ visit the new file."
 ;;; dbg! macro
 
 (defun rust-insert-dbg ()
-  "Insert the dbg! macro."
-  (cond ((region-active-p)
-         (when (< (mark) (point))
-           (exchange-point-and-mark))
-         (let ((old-point (point)))
-           (insert-parentheses)
-           (goto-char old-point)))
-        (t
-         (when (rust-in-str)
-           (up-list -1 t t))
-         (insert "(")
-         (forward-sexp)
-         (insert ")")
-         (backward-sexp)))
-  (insert "dbg!"))
+  "Insert the dbg! macro. Move cursor to the end of macro."
+  (when (rust-in-str)
+    (up-list -1 t t))
+  (insert "(")
+  (forward-sexp)
+  (insert ")")
+  (backward-sexp)
+  (insert "dbg!")
+  (forward-sexp))
+
+(defun rust-insert-dbg-region ()
+  "Insert the dbg! macro around a region. Move cursor to the end of macro."
+  (when (< (mark) (point))
+    (exchange-point-and-mark))
+  (let ((old-point (point)))
+    (insert-parentheses)
+    (goto-char old-point))
+  (insert "dbg!")
+  (forward-sexp))
+
+(defun rust-insert-dbg-alone ()
+  "Insert the dbg! macro alone. Move cursor in between the brackets."
+  (insert "dbg!()")
+  (backward-char))
 
 ;;;###autoload
 (defun rust-dbg-wrap-or-unwrap ()
   "Either remove or add the dbg! macro."
   (interactive)
-  (save-excursion
-    (if (region-active-p)
-        (rust-insert-dbg)
-
-      (let ((beginning-of-symbol (ignore-errors (beginning-of-thing 'symbol))))
-        (when beginning-of-symbol
-          (goto-char beginning-of-symbol)))
-
-      (let ((dbg-point (save-excursion
-                         (or (and (looking-at-p "dbg!") (+ 4 (point)))
-                             (ignore-errors
-                               (while (not (rust-looking-back-str "dbg!"))
-                                 (backward-up-list))
-                               (point))))))
-        (cond (dbg-point
-               (goto-char dbg-point)
-               (delete-char -4)
-               (delete-pair))
-              (t (rust-insert-dbg)))))))
+
+  (cond
+
+   ;; region
+   ((region-active-p)
+    (rust-insert-dbg-region))
+
+   ;; alone
+   ((or (looking-at-p " *$") (looking-at-p " *//.*"))
+    (rust-insert-dbg-alone))
+
+   ;; symbol
+   (t
+    (let ((beginning-of-symbol (ignore-errors (beginning-of-thing 'symbol))))
+      (when beginning-of-symbol
+        (goto-char beginning-of-symbol)))
+
+    (let ((dbg-point (save-excursion
+                       (or (and (looking-at-p "dbg!") (+ 4 (point)))
+                           (ignore-errors
+                             (while (not (rust-looking-back-str "dbg!"))
+                               (backward-up-list))
+                             (point))))))
+      (cond (dbg-point
+             (goto-char dbg-point)
+             (delete-char -4)
+             (delete-pair))
+            (t (rust-insert-dbg)))))
+   )
+)
 
 (defun rust-toggle-mutability ()
   "Toggles the mutability of the variable defined on the current line"