Support curved quotes in doc strings

Emacs's traditional doc string style has been to quote symbols
`like this'.  This worked well on now-obsolete terminals where
` and ' were symmetric quotes, but nowadays curved quotes
‘like this’ look better.  Support quoting the new way too.
(Bug#20385)
* doc/lispref/tips.texi (Documentation Tips): Symbols can be quoted
‘like-this’ as well as `like-this'.
* etc/NEWS: Mention this.
* lisp/cedet/mode-local.el (overload-docstring-extension)
(mode-local-print-binding, mode-local-describe-bindings-2):
* lisp/cus-theme.el (describe-theme-1):
* lisp/descr-text.el (describe-text-properties-1, describe-char):
* lisp/emacs-lisp/checkdoc.el (checkdoc-this-string-valid-engine):
* lisp/emacs-lisp/cl-generic.el (cl--generic-describe):
* lisp/emacs-lisp/eieio-opt.el (eieio-help-class)
(eieio-help-constructor):
* lisp/emacs-lisp/package.el (describe-package-1):
* lisp/faces.el (describe-face):
* lisp/help-fns.el (help-fns--key-bindings)
(help-fns--compiler-macro, help-fns--parent-mode, help-fns--obsolete):
(help-fns--interactive-only, describe-function-1):
(describe-variable):
* lisp/help.el (describe-mode):
* lisp/international/mule-cmds.el (describe-input-method)
(describe-language-environment):
* lisp/international/mule-diag.el (describe-character-set)
(print-coding-system-briefly, list-input-methods)
(list-input-methods-1):
Insert curved quotes rather than grave accent and apostrophe.
* lisp/cedet/srecode/texi.el (srecode-texi-texify-docstring):
* lisp/emacs-lisp/checkdoc.el (checkdoc-this-string-valid-engine)
(checkdoc-proper-noun-region-engine):
* lisp/emacs-lisp/lisp-mode.el (lisp-el-font-lock-keywords-2)
(lisp-cl-font-lock-keywords-2):
* lisp/finder.el (finder-font-lock-keywords):
* lisp/gnus/gnus-art.el (gnus-button-alist):
* lisp/help-fns.el (help-do-arg-highlight)
(describe-function-1, describe-variable):
* lisp/help-mode.el (help-xref-symbol-regexp)
(help-xref-info-regexp, help-xref-url-regexp):
* lisp/help.el (describe-mode):
* lisp/international/mule-cmds.el (help-xref-mule-regexp-template):
* lisp/wid-edit.el (widget-documentation-link-regexp):
Parse symbols quoted ‘like-this’ as well as `like-this'.
* lisp/progmodes/elisp-mode.el (emacs-lisp-mode):
Add "‘" and "’" to electric-pair-text-pairs.
(elisp--form-quoted-p): Also allow "‘" as a quoting char.
(elisp-completion-at-point, elisp--preceding-sexp):
Also treat "‘" and "’" as quoting chars.

5 files changed, 30 insertions, 28 deletions

diff --git a/lisp/emacs-lisp/checkdoc.el b/lisp/emacs-lisp/checkdoc.el
index 18361c8888f..4761ac5e6fc 100644
--- a/lisp/emacs-lisp/checkdoc.el
+++ b/lisp/emacs-lisp/checkdoc.el
@@ -1524,7 +1524,7 @@ may require more formatting")
      ;;     Instead, use the `\\[...]' construct to stand for them.
      (save-excursion
        (let ((f nil) (m nil) (start (point))
-	     (re "[^`A-Za-z0-9_]\\([CMA]-[a-zA-Z]\\|\\(\\([CMA]-\\)?\
+	     (re "[^`‘A-Za-z0-9_]\\([CMA]-[a-zA-Z]\\|\\(\\([CMA]-\\)?\
 mouse-[0-3]\\)\\)\\>"))
 	 ;; Find the first key sequence not in a sample
 	 (while (and (not f) (setq m (re-search-forward re e t)))
@@ -1554,7 +1554,8 @@ mouse-[0-3]\\)\\)\\>"))
      (save-excursion
        (let ((case-fold-search t)
 	     (ret nil) mb me)
-	 (while (and (re-search-forward "`\\(\\sw\\(\\sw\\|\\s_\\)+\\)'" e t)
+	 (while (and (re-search-forward
+                      "[`‘]\\(\\sw\\(\\sw\\|\\s_\\)+\\)['’]" e t)
 		     (not ret))
 	   (let* ((ms1 (match-string 1))
 		  (sym (intern-soft ms1)))
@@ -1785,16 +1786,17 @@ Replace with \"%s\"? " original replace)
 	     )))
      ;;* When a documentation string refers to a Lisp symbol, write it as
      ;;  it would be printed (which usually means in lower case), with
-     ;;  single-quotes around it.  For example: `lambda'.  There are two
-     ;;  exceptions: write t and nil without single-quotes.  (In this
-     ;;  manual, we normally do use single-quotes for those symbols.)
+     ;;  single-quotes around it.  For example: ‘lambda’.  There are two
+     ;;  exceptions: write t and nil without single-quotes.  (For
+     ;;  compatibility with an older Emacs style, quoting with ` and '
+     ;;  also works, e.g., `lambda' is treated like ‘lambda’.)
      (save-excursion
        (let ((found nil) (start (point)) (msg nil) (ms nil))
 	 (while (and (not msg)
 		     (re-search-forward
 		      ;; Ignore manual page references like
 		      ;; git-config(1).
-		      "[^-([`':a-zA-Z]\\(\\w+[:-]\\(\\w\\|\\s_\\)+\\)[^](']"
+		      "[^-([`'‘’:a-zA-Z]\\(\\w+[:-]\\(\\w\\|\\s_\\)+\\)[^]('’]"
 		      e t))
 	   (setq ms (match-string 1))
 	   ;; A . is a \s_ char, so we must remove periods from
@@ -1812,7 +1814,7 @@ Replace with \"%s\"? " original replace)
 		 (if (checkdoc-autofix-ask-replace
 		      (match-beginning 1) (+ (match-beginning 1)
 					     (length ms))
-		      msg (concat "`" ms "'") t)
+		      msg (concat "‘" ms "’") t)
 		     (setq msg nil)
 		   (setq msg
 			 (format "Lisp symbol `%s' should appear in quotes"
@@ -1824,7 +1826,7 @@ Replace with \"%s\"? " original replace)
 	   nil)))
      ;; t and nil case
      (save-excursion
-       (if (re-search-forward "\\(`\\(t\\|nil\\)'\\)" e t)
+       (if (re-search-forward "\\([`‘]\\(t\\|nil\\)['’]\\)" e t)
 	   (if (checkdoc-autofix-ask-replace
 		(match-beginning 1) (match-end 1)
 		(format "%s should not appear in quotes.  Remove? "
@@ -1989,7 +1991,7 @@ If the offending word is in a piece of quoted text, then it is skipped."
             (if (and (not (save-excursion
                             (goto-char b)
                             (forward-char -1)
-                            (looking-at "`\\|\"\\|\\.\\|\\\\")))
+                            (looking-at "[`\".‘]\\|\\\\")))
                      ;; surrounded by /, as in a URL or filename: /emacs/
                      (not (and (= ?/ (char-after e))
                                (= ?/ (char-before b))))
diff --git a/lisp/emacs-lisp/cl-generic.el b/lisp/emacs-lisp/cl-generic.el
index 24a04d445de..96b86aa21cc 100644
--- a/lisp/emacs-lisp/cl-generic.el
+++ b/lisp/emacs-lisp/cl-generic.el
@@ -876,11 +876,11 @@ Can only be used from within the lexical body of a primary or around method."
                                    (cl--generic-method-specializers method)))
                    (file (find-lisp-object-file-name met-name 'cl-defmethod)))
               (when file
-                (insert " in `")
+                (insert " in ‘")
                 (help-insert-xref-button (help-fns-short-filename file)
                                          'help-function-def met-name file
                                          'cl-defmethod)
-                (insert "'.\n")))
+                (insert "’.\n")))
             (insert "\n" (or (nth 2 info) "Undocumented") "\n\n")))))))
 
 ;;; Support for (head <val>) specializers.
diff --git a/lisp/emacs-lisp/eieio-opt.el b/lisp/emacs-lisp/eieio-opt.el
index 02b89e043e4..11d99849a97 100644
--- a/lisp/emacs-lisp/eieio-opt.el
+++ b/lisp/emacs-lisp/eieio-opt.el
@@ -90,11 +90,11 @@ If CLASS is actually an object, then also display current values of that object.
 	  " class")
   (let ((location (find-lisp-object-file-name class 'eieio-defclass)))
     (when location
-      (insert " in `")
+      (insert " in ‘")
       (help-insert-xref-button
        (help-fns-short-filename location)
        'eieio-class-def class location 'eieio-defclass)
-      (insert "'")))
+      (insert "’")))
   (insert ".\n")
   ;; Parents
   (let ((pl (eieio-class-parents class))
@@ -103,10 +103,10 @@ If CLASS is actually an object, then also display current values of that object.
       (insert " Inherits from ")
       (while (setq cur (pop pl))
 	(setq cur (eieio--class-name cur))
-	(insert "`")
+	(insert "‘")
 	(help-insert-xref-button (symbol-name cur)
 				 'help-function cur)
-	(insert (if pl "', " "'")))
+	(insert (if pl "’, " "’")))
       (insert ".\n")))
   ;; Children
   (let ((ch (eieio-class-children class))
@@ -114,10 +114,10 @@ If CLASS is actually an object, then also display current values of that object.
     (when ch
       (insert " Children ")
       (while (setq cur (pop ch))
-	(insert "`")
+	(insert "‘")
 	(help-insert-xref-button (symbol-name cur)
 				 'help-function cur)
-	(insert (if ch "', " "'")))
+	(insert (if ch "’, " "’")))
       (insert ".\n")))
   ;; System documentation
   (let ((doc (documentation-property class 'variable-documentation)))
@@ -130,9 +130,9 @@ If CLASS is actually an object, then also display current values of that object.
     (when generics
       (insert (propertize "Specialized Methods:\n\n" 'face 'bold))
       (dolist (generic generics)
-        (insert "`")
+        (insert "‘")
         (help-insert-xref-button (symbol-name generic) 'help-function generic)
-        (insert "'")
+        (insert "’")
 	(pcase-dolist (`(,qualifiers ,args ,doc)
                        (eieio-method-documentation generic class))
           (insert (format " %s%S\n" qualifiers args)
@@ -245,11 +245,11 @@ are not abstract."
 	(setq location
 	      (find-lisp-object-file-name ctr def)))
       (when location
-	(insert " in `")
+	(insert " in ‘")
 	(help-insert-xref-button
 	 (help-fns-short-filename location)
 	 'eieio-class-def ctr location 'eieio-defclass)
-	(insert "'"))
+	(insert "’"))
       (insert ".\nCreates an object of class " (symbol-name ctr) ".")
       (goto-char (point-max))
       (if (autoloadp def)
diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index 6facf576055..ab01a109b7a 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -403,8 +403,8 @@
          ;; Words inside \\[] tend to be for `substitute-command-keys'.
          ("\\\\\\\\\\[\\(\\(?:\\sw\\|\\s_\\)+\\)\\]"
           (1 font-lock-constant-face prepend))
-         ;; Words inside `' tend to be symbol names.
-         ("`\\(\\(?:\\sw\\|\\s_\\)\\(?:\\sw\\|\\s_\\)+\\)'"
+         ;; Words inside ‘’ and `' tend to be symbol names.
+         ("[`‘]\\(\\(?:\\sw\\|\\s_\\)\\(?:\\sw\\|\\s_\\)+\\)['’]"
           (1 font-lock-constant-face prepend))
          ;; Constant values.
          ("\\_<:\\(?:\\sw\\|\\s_\\)+\\_>" 0 font-lock-builtin-face)
@@ -452,8 +452,8 @@
          ;; Erroneous structures.
          (,(concat "(" cl-errs-re "\\_>")
            (1 font-lock-warning-face))
-         ;; Words inside `' tend to be symbol names.
-         ("`\\(\\(?:\\sw\\|\\s_\\)\\(?:\\sw\\|\\s_\\)+\\)'"
+         ;; Words inside ‘’ and `' tend to be symbol names.
+         ("[`‘]\\(\\(?:\\sw\\|\\s_\\)\\(?:\\sw\\|\\s_\\)+\\)['’]"
           (1 font-lock-constant-face prepend))
          ;; Constant values.
          ("\\_<:\\(?:\\sw\\|\\s_\\)+\\_>" 0 font-lock-builtin-face)
diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 3d5afa3edd2..97e6bd63da9 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -2137,17 +2137,17 @@ will be deleted."
                                    "Installed"
                                  (capitalize status)) ;FIXME: Why comment-face?
                                'font-lock-face 'font-lock-comment-face))
-           (insert " in `")
+           (insert " in ‘")
            ;; Todo: Add button for uninstalling.
            (help-insert-xref-button (abbreviate-file-name
                                      (file-name-as-directory pkg-dir))
                                     'help-package-def pkg-dir)
            (if (and (package-built-in-p name)
                     (not (package-built-in-p name version)))
-               (insert "',\n             shadowing a "
+               (insert "’,\n             shadowing a "
                        (propertize "built-in package"
                                    'font-lock-face 'font-lock-builtin-face))
-             (insert "'"))
+             (insert "’"))
            (if signed
                (insert ".")
              (insert " (unsigned)."))