* lisp/emacs-lisp/lisp-mode.el (indent-sexp): Simplify.

* test/lisp/emacs-lisp/lisp-mode-tests.el (indent-sexp):
(indent-subsexp, indent-sexp-in-string): New tests.

2 files changed, 166 insertions, 96 deletions

diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index c2f5f42ace8..5faa6a50ae5 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -1069,103 +1069,79 @@ Lisp function does not specify a special indentation."
 If optional arg ENDPOS is given, indent each line, stopping when
 ENDPOS is encountered."
   (interactive)
-  (let ((indent-stack (list nil))
-        (next-depth 0)
-        ;; If ENDPOS is non-nil, use nil as STARTING-POINT
-        ;; so that calculate-lisp-indent will find the beginning of
-        ;; the defun we are in.
-        ;; If ENDPOS is nil, it is safe not to scan before point
-        ;; since every line we indent is more deeply nested than point is.
-        (starting-point (if endpos nil (point)))
-        (last-point (point))
-        last-depth bol outer-loop-done inner-loop-done state this-indent)
-    (or endpos
-        ;; Get error now if we don't have a complete sexp after point.
-        (save-excursion (forward-sexp 1)))
+  (let* ((indent-stack (list nil))
+         ;; If ENDPOS is non-nil, use beginning of defun as STARTING-POINT.
+         ;; If ENDPOS is nil, it is safe not to scan before point
+         ;; since every line we indent is more deeply nested than point is.
+         (starting-point (save-excursion (if endpos (beginning-of-defun))
+                                         (point)))
+         (state nil)
+         (init-depth 0)
+         (next-depth 0)
+         (last-depth 0)
+         (last-syntax-point (point)))
+    (unless endpos
+      ;; Get error now if we don't have a complete sexp after point.
+      (save-excursion (forward-sexp 1)
+                      ;; We need a marker because we modify the buffer
+                      ;; text preceding endpos.
+                      (setq endpos (point-marker))))
     (save-excursion
-      (setq outer-loop-done nil)
-      (while (if endpos (< (point) endpos)
-               (not outer-loop-done))
-        (setq last-depth next-depth
-              inner-loop-done nil)
-        ;; Parse this line so we can learn the state
-        ;; to indent the next line.
-        ;; This inner loop goes through only once
-        ;; unless a line ends inside a string.
-        (while (and (not inner-loop-done)
-                    (not (setq outer-loop-done (eobp))))
-          (setq state (parse-partial-sexp (point) (progn (end-of-line) (point))
-                                          nil nil state))
-          (setq next-depth (car state))
-          ;; If the line contains a comment other than the sort
-          ;; that is indented like code,
-          ;; indent it now with indent-for-comment.
-          ;; Comments indented like code are right already.
-          ;; In any case clear the in-comment flag in the state
-          ;; because parse-partial-sexp never sees the newlines.
-          (if (car (nthcdr 4 state))
-              (progn (indent-for-comment)
-                     (end-of-line)
-                     (setcar (nthcdr 4 state) nil)))
-          ;; If this line ends inside a string,
-          ;; go straight to next line, remaining within the inner loop,
-          ;; and turn off the \-flag.
-          (if (car (nthcdr 3 state))
-              (progn
-                (forward-line 1)
-                (setcar (nthcdr 5 state) nil))
-            (setq inner-loop-done t)))
-        (and endpos
-             (<= next-depth 0)
-             (progn
-               (setq indent-stack (nconc indent-stack
-                                         (make-list (- next-depth) nil))
-                     last-depth (- last-depth next-depth)
-                     next-depth 0)))
-        (forward-line 1)
-        ;; Decide whether to exit.
-        (if endpos
-            ;; If we have already reached the specified end,
-            ;; give up and do not reindent this line.
-            (if (<= endpos (point))
-                (setq outer-loop-done t))
-          ;; If no specified end, we are done if we have finished one sexp.
-          (if (<= next-depth 0)
-              (setq outer-loop-done t)))
-        (unless outer-loop-done
-          (while (> last-depth next-depth)
-            (setq indent-stack (cdr indent-stack)
-                  last-depth (1- last-depth)))
-          (while (< last-depth next-depth)
-            (setq indent-stack (cons nil indent-stack)
-                  last-depth (1+ last-depth)))
-          ;; Now indent the next line according
-          ;; to what we learned from parsing the previous one.
-          (setq bol (point))
-          (skip-chars-forward " \t")
-          ;; But not if the line is blank, or just a comment
-          ;; (except for double-semi comments; indent them as usual).
-          (if (or (eobp) (looking-at "\\s<\\|\n"))
-              nil
-            (if (and (car indent-stack)
-                     (>= (car indent-stack) 0))
-                (setq this-indent (car indent-stack))
-              (let ((val (calculate-lisp-indent
-                          (if (car indent-stack) (- (car indent-stack))
-                            starting-point))))
-                (if (null val)
-                    (setq this-indent val)
-                  (if (integerp val)
-                      (setcar indent-stack
-                              (setq this-indent val))
-                    (setcar indent-stack (- (car (cdr val))))
-                    (setq this-indent (car val))))))
-            (if (and this-indent (/= (current-column) this-indent))
-                (progn (delete-region bol (point))
-                       (indent-to this-indent)))))
-        (or outer-loop-done
-            (setq outer-loop-done (= (point) last-point))
-            (setq last-point (point)))))))
+      (while (< (point) endpos)
+        ;; Parse this line so we can learn the state to indent the
+        ;; next line.
+        (while (progn
+                 (setq state (parse-partial-sexp
+                              last-syntax-point (progn (end-of-line) (point))
+                              nil nil state))
+                 ;; Skip over newlines within strings.
+                 (nth 3 state))
+          (setq state (parse-partial-sexp (point) (point-max)
+                                          nil nil state 'syntax-table))
+          (setq last-syntax-point (point)))
+        (setq next-depth (car state))
+        ;; If the line contains a comment indent it now with
+        ;; `indent-for-comment'.
+        (when (nth 4 state)
+          (indent-for-comment)
+          (end-of-line))
+        (setq last-syntax-point (point))
+        (when (< next-depth init-depth)
+          (setq indent-stack (nconc indent-stack
+                                    (make-list (- init-depth next-depth) nil))
+                last-depth (- last-depth next-depth)
+                next-depth init-depth))
+        (forward-line 1)
+        (when (< (point) endpos)
+          (let ((depth-delta (- next-depth last-depth)))
+            (cond ((< depth-delta 0)
+                   (setq indent-stack (nthcdr (- depth-delta) indent-stack)))
+                  ((> depth-delta 0)
+                   (setq indent-stack (nconc (make-list depth-delta nil)
+                                             indent-stack))))
+            (setq last-depth next-depth))
+          ;; Now indent the next line according
+          ;; to what we learned from parsing the previous one.
+          (skip-chars-forward " \t")
+          ;; But not if the line is blank, or just a comment (we
+          ;; already called `indent-for-comment' above).
+          (unless (or (eolp) (eq (char-syntax (char-after)) ?<))
+            (let ((this-indent (car indent-stack)))
+              (when (listp this-indent)
+                (let ((val (calculate-lisp-indent
+                            (or (car this-indent) starting-point))))
+                  (setq
+                   this-indent
+                   (cond ((integerp val)
+                          (setf (car indent-stack) val))
+                         ((consp val) ; (COLUMN CONTAINING-SEXP-START)
+                          (setf (car indent-stack) (cdr val))
+                          (car val))
+                         ;; `calculate-lisp-indent' only returns nil
+                         ;; when we're in a string, but this won't
+                         ;; happen because we skip strings above.
+                         (t (error "This shouldn't happen!"))))))
+              (indent-line-to this-indent))))))))
 
 (defun indent-pp-sexp (&optional arg)
   "Indent each line of the list starting just after point, or prettyprint it.
diff --git a/test/lisp/emacs-lisp/lisp-mode-tests.el b/test/lisp/emacs-lisp/lisp-mode-tests.el
new file mode 100644
index 00000000000..2801f23df63
--- /dev/null
+++ b/test/lisp/emacs-lisp/lisp-mode-tests.el
@@ -0,0 +1,94 @@
+;;; lisp-mode-tests.el --- Test Lisp editing commands  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2017 Free Software Foundation, Inc.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'cl-lib)
+(require 'lisp-mode)
+
+(ert-deftest indent-sexp ()
+  "Test basics of \\[indent-sexp]."
+  (with-temp-buffer
+    (insert "\
+\(a
+ (prog1
+     (prog1
+         1
+       2)
+   2)
+ (1
+  \"string
+noindent\" (\"string2
+noindent\" 3
+4)
+  2)                                    ; comment
+ ;; comment
+ b)")
+    (goto-char (point-min))
+    (let ((indent-tabs-mode nil)
+          (correct (buffer-string)))
+      (dolist (mode '(fundamental-mode emacs-lisp-mode))
+        (funcall mode)
+        (indent-sexp)
+        ;; Don't mess up correctly indented code.
+        (should (string= (buffer-string) correct))
+        ;; Correctly add indentation.
+        (save-excursion
+          (while (not (eobp))
+            (delete-horizontal-space)
+            (forward-line)))
+        (indent-sexp)
+        (should (equal (buffer-string) correct))
+        ;; Correctly remove indentation.
+        (save-excursion
+          (let ((n 0))
+            (while (not (eobp))
+              (unless (looking-at "noindent")
+                (insert (make-string n ?\s)))
+              (cl-incf n)
+              (forward-line))))
+        (indent-sexp)
+        (should (equal (buffer-string) correct))))))
+
+(ert-deftest indent-subsexp ()
+  "Make sure calling `indent-sexp' inside a sexp works."
+  (with-temp-buffer
+    (insert "\
+\(d1 xx
+    (d2 yy
+        zz)
+    11)")
+    (let ((correct (buffer-string)))
+      (search-backward "d2")
+      (up-list -1)
+      (indent-sexp)
+      (should (equal (buffer-string) correct)))))
+
+(ert-deftest indent-sexp-in-string ()
+  "Make sure calling `indent-sexp' inside a string works."
+  ;; See https://debbugs.gnu.org/cgi/bugreport.cgi?bug=21343.
+  (with-temp-buffer
+    (emacs-lisp-mode)
+    (insert "\";\"")
+    (let ((correct (buffer-string)))
+      (search-backward ";")
+      (indent-sexp)
+      (should (equal (buffer-string) correct)))))
+
+(provide 'lisp-mode-tests)
+;;; lisp-mode-tests.el ends here