master 38037e0: Indent bodies of local function definitions properly in elisp-mode

[Lars Ingebrigtsen]

branch: master
commit 38037e04cb05cb1f2b604f0b1602d36b0bcf6985
Author: akater <nuclearspace@gmail.com>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Indent bodies of local function definitions properly in elisp-mode
    
    * lisp/emacs-lisp/lisp-mode.el (lisp-indent-function): Check for
    local defforms (`cl-flet' and `cl-labels').
    (lisp--local-defform-body): New auxiliary function (bug#9622).
---
 etc/NEWS                                |  8 ++++++
 lisp/emacs-lisp/lisp-mode.el            | 45 +++++++++++++++++++++++++--------
 test/lisp/emacs-lisp/lisp-mode-tests.el | 11 ++++++++
 3 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index c266ddd..2f8fbc7 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -3220,6 +3220,14 @@ file:
 
     (add-hook 'foo-mode-hook (lambda () (auto-fill-mode -1))
 
+---
+** Indentation of 'cl-flet' and 'cl-labels' has changed.
+These forms now indent like this:
+
+    (cl-flet ((bla (x)
+               (* x x)))
+      (bla 42))
+
 
 * Incompatible Lisp Changes in Emacs 28.1
 
diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index eac3c03..7ce857e 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -29,6 +29,7 @@
 ;;; Code:
 
 (eval-when-compile (require 'cl-lib))
+(eval-when-compile (require 'subr-x))
 
 (defvar font-lock-comment-face)
 (defvar font-lock-doc-face)
@@ -1105,6 +1106,27 @@ is the buffer position of the start of the containing 
expression."
               (t
                normal-indent))))))
 
+(defun lisp--local-defform-body (state)
+  "Return non-nil if at local definition body according to STATE.
+STATE is the `parse-partial-sexp' state for current position."
+  (when-let ((start-of-innermost-containing-list (nth 1 state)))
+    (let* ((parents (nth 9 state))
+           (second-cons-after (cddr parents))
+           second-order-parent)
+      (while second-cons-after
+        (when (= start-of-innermost-containing-list
+                 (car second-cons-after))
+          (setq second-order-parent (car parents)
+                ;; Leave the loop.
+                second-cons-after nil))
+        (pop second-cons-after)
+        (pop parents))
+      (and second-order-parent
+           (save-excursion
+             (goto-char (1+ second-order-parent))
+             (memq (read (current-buffer))
+                   '(cl-flet cl-labels)))))))
+
 (defun lisp-indent-function (indent-point state)
   "This function is the normal value of the variable `lisp-indent-function'.
 The function `calculate-lisp-indent' calls this to determine
@@ -1138,16 +1160,17 @@ Lisp function does not specify a special indentation."
     (if (and (elt state 2)
              (not (looking-at "\\sw\\|\\s_")))
         ;; car of form doesn't seem to be a symbol
-        (progn
+        (if (lisp--local-defform-body state)
+            (lisp-indent-defform state indent-point)
           (if (not (> (save-excursion (forward-line 1) (point))
                       calculate-lisp-indent-last-sexp))
-               (progn (goto-char calculate-lisp-indent-last-sexp)
-                      (beginning-of-line)
-                      (parse-partial-sexp (point)
-                                          calculate-lisp-indent-last-sexp 0 
t)))
-           ;; Indent under the list or under the first sexp on the same
-           ;; line as calculate-lisp-indent-last-sexp.  Note that first
-           ;; thing on that line has to be complete sexp since we are
+             (progn (goto-char calculate-lisp-indent-last-sexp)
+                    (beginning-of-line)
+                    (parse-partial-sexp (point)
+                                        calculate-lisp-indent-last-sexp 0 t)))
+         ;; Indent under the list or under the first sexp on the same
+         ;; line as calculate-lisp-indent-last-sexp.  Note that first
+         ;; thing on that line has to be complete sexp since we are
           ;; inside the innermost containing sexp.
           (backward-prefix-chars)
           (current-column))
@@ -1160,13 +1183,15 @@ Lisp function does not specify a special indentation."
        (cond ((or (eq method 'defun)
                   (and (null method)
                        (> (length function) 3)
-                       (string-match "\\`def" function)))
+                       (string-match "\\`def" function))
+                   ;; Check whether we are in flet or labels.
+                   (lisp--local-defform-body state))
               (lisp-indent-defform state indent-point))
              ((integerp method)
               (lisp-indent-specform method state
                                     indent-point normal-indent))
              (method
-               (funcall method indent-point state)))))))
+              (funcall method indent-point state)))))))
 
 (defcustom lisp-body-indent 2
   "Number of columns to indent the second line of a `(def...)' form."
diff --git a/test/lisp/emacs-lisp/lisp-mode-tests.el 
b/test/lisp/emacs-lisp/lisp-mode-tests.el
index e2cecdf..5e533b3 100644
--- a/test/lisp/emacs-lisp/lisp-mode-tests.el
+++ b/test/lisp/emacs-lisp/lisp-mode-tests.el
@@ -330,5 +330,16 @@ Expected initialization file: `%s'\"
       (faceup-clean-buffer)
       (should (faceup-test-font-lock-buffer 'emacs-lisp-mode faceup)))))
 
+(ert-deftest test-cl-flet-indentation ()
+  (should (equal
+           (with-temp-buffer
+             (lisp-mode)
+             (insert "(cl-flet ((bla (x)\n(* x x)))\n(bla 42))")
+             (indent-region (point-min) (point-max))
+             (buffer-string))
+            "(cl-flet ((bla (x)
+              (* x x)))
+  (bla 42))")))
+
 (provide 'lisp-mode-tests)
 ;;; lisp-mode-tests.el ends here