master 10696d0: Make delete-pair only delete pairs that are part of insert-pair-alist

[Lars Ingebrigtsen]

branch: master
commit 10696d0ac51b9a92359ab7cb2c2e0a28d186dd52
Author: martin rudalics <rudalics@gmx.at>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Make delete-pair only delete pairs that are part of insert-pair-alist
    
    * lisp/emacs-lisp/lisp.el (delete-pair): Only delete pairs that
    are part of `insert-pair-alist' (bug#4136).
---
 lisp/emacs-lisp/lisp.el            | 37 +++++++++++++++++++++++++++++++------
 test/lisp/emacs-lisp/lisp-tests.el |  3 +--
 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/lisp/emacs-lisp/lisp.el b/lisp/emacs-lisp/lisp.el
index 8c18557..ac4ba78 100644
--- a/lisp/emacs-lisp/lisp.el
+++ b/lisp/emacs-lisp/lisp.el
@@ -735,12 +735,37 @@ This command assumes point is not in a string or comment."
   (insert-pair arg ?\( ?\)))
 
 (defun delete-pair (&optional arg)
-  "Delete a pair of characters enclosing ARG sexps following point.
-A negative ARG deletes a pair of characters around preceding ARG sexps."
-  (interactive "p")
-  (unless arg (setq arg 1))
-  (save-excursion (forward-sexp arg) (delete-char (if (> arg 0) -1 1)))
-  (delete-char (if (> arg 0) 1 -1)))
+  "Delete a pair of characters enclosing ARG sexps that follow point.
+A negative ARG deletes a pair around the preceding ARG sexps instead."
+  (interactive "P")
+  (if arg
+      (setq arg (prefix-numeric-value arg))
+    (setq arg 1))
+  (if (< arg 0)
+      (save-excursion
+       (skip-chars-backward " \t")
+       (save-excursion
+         (let ((close-char (char-before)))
+           (forward-sexp arg)
+           (unless (member (list (char-after) close-char)
+                           (mapcar (lambda (p)
+                                     (if (= (length p) 3) (cdr p) p))
+                                   insert-pair-alist))
+             (error "Not after matching pair"))
+           (delete-char 1)))
+       (delete-char -1))
+    (save-excursion
+      (skip-chars-forward " \t")
+      (save-excursion
+       (let ((open-char (char-after)))
+         (forward-sexp arg)
+         (unless (member (list open-char (char-before))
+                         (mapcar (lambda (p)
+                                   (if (= (length p) 3) (cdr p) p))
+                                 insert-pair-alist))
+           (error "Not before matching pair"))
+         (delete-char -1)))
+      (delete-char 1))))
 
 (defun raise-sexp (&optional arg)
   "Raise ARG sexps higher up the tree."
diff --git a/test/lisp/emacs-lisp/lisp-tests.el 
b/test/lisp/emacs-lisp/lisp-tests.el
index a2b8304..1476574 100644
--- a/test/lisp/emacs-lisp/lisp-tests.el
+++ b/test/lisp/emacs-lisp/lisp-tests.el
@@ -136,8 +136,7 @@
     (text-mode)
     (insert "\"foo\"")
     (goto-char (point-min))
-    (delete-pair)
-    (should (string-equal "fo\"" (buffer-string)))))
+    (should-error (delete-pair))))
 
 (ert-deftest lisp-delete-pair-quotes-text-mode-syntax-table ()
   "Test \\[delete-pair] with modified Text Mode syntax for #15014."