main 510d82b3: Add folding support for TeX quotes

[Ikumi Keita]

branch: main
commit 510d82b3b356dbbd007fd085662afea99e947fb7
Author: Paul Nelson <ultrono@gmail.com>
Commit: Ikumi Keita <ikumi@ikumi.que.jp>

    Add folding support for TeX quotes
    
    * tex-fold.el (TeX-fold--verb-data):
    (TeX-fold-verbs): Move, unchanged, to a new part of the file
    consisting of functions used for TeX-fold-region-functions.
    (TeX-fold--make-misc-overlay): Deleted; now subsumed by
    TeX-fold-make-overlay.
    (TeX-fold-make-overlay): New optional argument display-string,
    used to subsume TeX-fold--make-misc-overlay.
    (TeX-fold-open-quote):
    (TeX-fold-close-quote):
    (TeX-fold-quotes-on-insert): New user options.
    (TeX-fold-quotes): New function, using the new user options.
    (TeX-fold-region-functions): Add TeX-fold-quotes.
    * tex.el (TeX-get-quote-characters): New helper
    function, extracted from TeX-insert-quote.
    (TeX-insert-quote): Use the new helper function, as well as the
    new user option, TeX-fold-quotes-on-insert.
    * auctex.texi (Folding Macros and Environments): Document the
    new user options.
---
 doc/auctex.texi |  33 +++++++---
 tex-fold.el     | 184 +++++++++++++++++++++++++++++++++++---------------------
 tex.el          |  55 +++++++++++++----
 3 files changed, 181 insertions(+), 91 deletions(-)

diff --git a/doc/auctex.texi b/doc/auctex.texi
index 4c4a900c..718d4c2a 100644
--- a/doc/auctex.texi
+++ b/doc/auctex.texi
@@ -2651,7 +2651,8 @@ around the mark will be kept unfolded.
 @defopt TeX-fold-region-functions
 This variable is a list of functions which allow the user, or external
 packages, to fold additional @LaTeX{} constructs beyond those supported by
-default.
+default.  By default, it is configured to support folding for verbatim
+environments and quotes.
 @end defopt
 
 @deffn Command TeX-fold-region
@@ -2957,13 +2958,29 @@ specifications for @samp{begin} and @samp{end} from
 
 @defopt TeX-fold-bib-file
 The default folding behavior for @samp{\cite@{...@}} macros that point to
-a BibTeX entry is to replace them with a string of the form [XYZ99],
-formed using the authors' last names and the publication year.  If
-@AUCTeX{} cannot find the required BibTeX entries in any bib files
-included in the current document, then, as a backup, it searches the files
-specified in @code{TeX-fold-bib-file}.  This may be useful when using
-@samp{\thebibliography@{...@}} rather than BibTeX, or when working in
-non-file buffers.
+a Bib@TeX{} entry is to replace them with a string of the form
+@samp{[XYZ99]}, formed using the authors' last names and the publication
+year.  If @AUCTeX{} cannot find the required Bib@TeX{} entries in any bib
+files included in the current document, then, as a backup, it searches the
+files specified in @code{TeX-fold-bib-file}.  This may be useful when
+using @samp{\thebibliography@{...@}} rather than Bib@TeX{}, or when
+working in non-file buffers.
+@end defopt
+
+@defopt TeX-fold-open-quote
+Folded version of opening quote.  This string is used to replace opening
+quotes when folding @LaTeX{} quotes.
+@end defopt
+
+@defopt TeX-fold-close-quote
+Folded version of closing quote.  This string is used to replace closing
+quotes when folding @LaTeX{} quotes.
+@end defopt
+
+@defopt TeX-fold-quotes-on-insert
+If non-@code{nil}, automatically fold @LaTeX{} quotes when they are
+inserted.  This option is consulted by @code{TeX-insert-quote} when
+determining whether to fold newly inserted quotes.
 @end defopt
 
 @node Outline
diff --git a/tex-fold.el b/tex-fold.el
index b213602e..2c10cc27 100644
--- a/tex-fold.el
+++ b/tex-fold.el
@@ -56,6 +56,8 @@
 (declare-function LaTeX-verbatim-macro-boundaries "latex")
 (declare-function LaTeX-verbatim-macros-with-braces "latex")
 (declare-function LaTeX-verbatim-macros-with-delims "latex")
+(declare-function bibtex-parse-entry "bibtex")
+(declare-function bibtex-text-in-field "bibtex")
 
 (defgroup TeX-fold nil
   "Fold TeX macros."
@@ -361,53 +363,12 @@ and `TeX-fold-math-spec-list', and environments in 
`TeX-fold-env-spec-list'."
       (TeX-fold-clearout-region start end)
       (TeX-fold-region start end))))
 
-(defcustom TeX-fold-region-functions '(TeX-fold-verbs)
+(defcustom TeX-fold-region-functions '(TeX-fold-verbs TeX-fold-quotes)
   "List of additional functions to call when folding a region.
 Each function is called with two arguments, the start and end positions
 of the region to fold."
   :type '(repeat function)
-  :package-version '(auctex . "14.0.7"))
-
-(defun TeX-fold--verb-data (&rest _args)
-  "Return data describing verbatim macro at point.
-Returns list of the form (START END CONTENT).  This should be called
-only in LaTeX modes."
-  (when-let* ((boundaries (LaTeX-verbatim-macro-boundaries))
-              (bound-start (car boundaries))
-              (bound-end (cdr boundaries))
-              (end-delim-char (char-before bound-end))
-              (start-delim-char (if (= end-delim-char ?\})
-                                    ?\{
-                                  end-delim-char))
-              (start-delim (char-to-string start-delim-char))
-              (verb-arg-start
-               (1+ (progn
-                     (goto-char bound-end)
-                     (if (string= start-delim TeX-grop)
-                         (progn (backward-sexp) (point))
-                       (forward-char -1)
-                       (search-backward start-delim bound-start t)))))
-              (verb-arg-end (1- bound-end)))
-    (list bound-start
-          bound-end
-          (buffer-substring verb-arg-start verb-arg-end))))
-
-(defun TeX-fold-verbs (start end)
-  "In LaTeX modes, fold verbatim macros between START and END."
-  (when (derived-mode-p 'LaTeX-mode)
-    (save-excursion
-      (goto-char start)
-      (let ((re (concat (regexp-quote TeX-esc)
-                        (regexp-opt
-                         (append
-                          (LaTeX-verbatim-macros-with-braces)
-                          (LaTeX-verbatim-macros-with-delims))))))
-        (while (let ((case-fold-search nil))
-                 (re-search-forward re end t))
-          (when-let* ((data (TeX-fold--verb-data))
-                      (spec (lambda (&rest _args)
-                              (nth 2 (TeX-fold--verb-data)))))
-            (apply #'TeX-fold--make-misc-overlay (append data (list 
spec)))))))))
+  :package-version '(auctex . "14.0.8"))
 
 (defun TeX-fold-region (start end)
   "Fold all items in region from START to END."
@@ -822,8 +783,6 @@ with some additional non-alphabetical characters such as 
braces."
 Return string of the form \"XYZ99\", formed using authors' last names and
 publication year, or nil if author/year not found."
   (require 'bibtex)
-  (declare-function bibtex-parse-entry "bibtex")
-  (declare-function bibtex-text-in-field "bibtex")
   (when-let* ((case-fold-search t)
               (entry (bibtex-parse-entry))
               (author (bibtex-text-in-field "author" entry))
@@ -898,14 +857,17 @@ using authors' last names and the the publication year."
 
 ;;; Utilities
 
-(defun TeX-fold-make-overlay (ov-start ov-end type display-string-spec)
+(defun TeX-fold-make-overlay (ov-start ov-end type display-string-spec
+                                       &optional display-string)
   "Make a TeX-fold overlay extending from OV-START to OV-END.
-TYPE is a symbol which is used to describe the content to hide
-and may be `macro' for macros, `math' for math macro and `env' for
-environments.
+TYPE is a symbol which is used to describe the content to hide and may
+be `macro' for macros, `math' for math macro, `env' for environments, or
+`misc' for miscellaneous constructs like quotes and dashes.
 DISPLAY-STRING-SPEC is the original specification of the display
 string in the variables `TeX-fold-macro-spec-list' and alikes.
-See its doc string for detail."
+See its doc string for detail.
+If DISPLAY-STRING is provided, it will be used directly as the overlay's
+display property."
   ;; Calculate priority before the overlay is instantiated.  We don't
   ;; want `TeX-overlay-prioritize' to pick up a non-prioritized one.
   (let ((priority (TeX-overlay-prioritize ov-start ov-end))
@@ -913,27 +875,11 @@ See its doc string for detail."
     (overlay-put ov 'category 'TeX-fold)
     (overlay-put ov 'priority priority)
     (overlay-put ov 'evaporate t)
-    (overlay-put ov 'TeX-fold-type type)
-    (overlay-put ov 'TeX-fold-display-string-spec display-string-spec)
-    ov))
-
-(defun TeX-fold--make-misc-overlay (start end display-string 
display-string-spec)
-  "Create a miscellaneous overlay between START and END.
-DISPLAY-STRING is the display string, while DISPLAY-STRING-SPEC is as in
-`TeX-fold-make-overlay'.
-
-This function is intended to be used with verbatim environments and
-other miscellaneous folding constructs.  By contrast, the function
-`TeX-fold-make-overlay' is used in the implementation of
-`TeX-fold-hide-item', which applies to typical macros, environments and
-math."
-  (let ((priority (TeX-overlay-prioritize start end))
-        (ov (make-overlay start end)))
-    (overlay-put ov 'category 'TeX-fold)
-    (overlay-put ov 'priority priority)
-    (overlay-put ov 'evaporate t)
-    (overlay-put ov 'display display-string)
+    (when type
+      (overlay-put ov 'TeX-fold-type type))
     (overlay-put ov 'TeX-fold-display-string-spec display-string-spec)
+    (when display-string
+      (overlay-put ov 'display display-string))
     ov))
 
 (defun TeX-fold-item-end (start type)
@@ -1397,6 +1343,104 @@ With zero or negative ARG turn mode off."
 ;;;###autoload
 (defalias 'tex-fold-mode #'TeX-fold-mode)
 
+;;; Miscellaneous folding
+
+;; This section provides functions for use in
+;; `TeX-fold-region-functions'.
+
+;;;; Verbatim constructs
+
+(defun TeX-fold--verb-data (&rest _args)
+  "Return data describing verbatim macro at point.
+Returns list of the form (START END CONTENT).  This should be called
+only in LaTeX modes."
+  (when-let* ((boundaries (LaTeX-verbatim-macro-boundaries))
+              (bound-start (car boundaries))
+              (bound-end (cdr boundaries))
+              (end-delim-char (char-before bound-end))
+              (start-delim-char (if (= end-delim-char ?\})
+                                    ?\{
+                                  end-delim-char))
+              (start-delim (char-to-string start-delim-char))
+              (verb-arg-start
+               (1+ (progn
+                     (goto-char bound-end)
+                     (if (string= start-delim TeX-grop)
+                         (progn (backward-sexp) (point))
+                       (forward-char -1)
+                       (search-backward start-delim bound-start t)))))
+              (verb-arg-end (1- bound-end)))
+    (list bound-start
+          bound-end
+          (buffer-substring verb-arg-start verb-arg-end))))
+
+(defun TeX-fold-verbs (start end)
+  "In LaTeX modes, fold verbatim macros between START and END.
+Replaces the verbatim content with its own text."
+  (when (derived-mode-p 'LaTeX-mode)
+    (save-excursion
+      (goto-char start)
+      (let ((re (concat (regexp-quote TeX-esc)
+                        (regexp-opt
+                         (append
+                          (LaTeX-verbatim-macros-with-braces)
+                          (LaTeX-verbatim-macros-with-delims))))))
+        (while (let ((case-fold-search nil))
+                 (re-search-forward re end t))
+          (when-let* ((data (TeX-fold--verb-data))
+                      (verb-start (nth 0 data))
+                      (verb-end (nth 1 data))
+                      (verb-content (nth 2 data)))
+            (TeX-fold-make-overlay
+             verb-start verb-end
+             'misc
+             (lambda (&rest _args)
+               (nth 2 (TeX-fold--verb-data)))
+             verb-content)))))))
+
+;;;; Quotes
+
+(defcustom TeX-fold-open-quote "“"
+  "Folded version of opening quote."
+  :type 'string
+  :package-version '(auctex . "14.0.8"))
+
+(defcustom TeX-fold-close-quote "”"
+  "Folded verison of closing quote."
+  :type 'string
+  :package-version '(auctex . "14.0.8"))
+
+(defcustom TeX-fold-quotes-on-insert nil
+  "Non-nil means to automatically fold LaTeX quotes when they are inserted.
+Consulted by `TeX-insert-quote'."
+  :type 'boolean
+  :package-version '(auctex . "14.0.8"))
+
+(defun TeX-fold-quotes (start end)
+  "Fold LaTeX quotes between START and END.
+Replaces opening and closing quotes with `TeX-fold-open-quote' and
+`TeX-fold-close-quote', respectively, except in math environments,
+verbatim contexts and comments."
+  (pcase-let ((`(,open-quote ,close-quote _) (TeX-get-quote-characters)))
+    (save-excursion
+      (goto-char start)
+      (let ((regexp (regexp-opt (list open-quote close-quote))))
+        (while (re-search-forward regexp end t)
+          (let ((str (if (string= (match-string-no-properties 0) open-quote)
+                         TeX-fold-open-quote
+                       TeX-fold-close-quote))
+                (quote-start (match-beginning 0))
+                (quote-end (match-end 0)))
+            (unless (or (and (fboundp 'font-latex-faces-present-p)
+                             (font-latex-faces-present-p
+                              '(tex-math
+                                font-latex-verbatim-face
+                                font-latex-math-face
+                                font-lock-comment-face)
+                              quote-start))
+                        (texmathp))
+              (TeX-fold-make-overlay quote-start quote-end 'misc str 
str))))))))
+
 (provide 'tex-fold)
 
 ;;; tex-fold.el ends here
diff --git a/tex.el b/tex.el
index 94d72afa..498464e0 100644
--- a/tex.el
+++ b/tex.el
@@ -6386,6 +6386,24 @@ the settings of style files.  Style files should 
therefore check
 if this symbol is present and not alter `TeX-quote-language' if
 it is.")
 
+(defun TeX-get-quote-characters ()
+  "Get appropriate open and close quote strings.
+Return list consisting of three elements as in
+`TeX-quote-language-alist'."
+  (let* ((lang-override (if (eq (car TeX-quote-language) 'override)
+                            TeX-quote-language
+                          (assoc (car TeX-quote-language)
+                                 TeX-quote-language-alist)))
+         (lang (or lang-override TeX-quote-language))
+         (open-quote (if lang (nth 1 lang) TeX-open-quote))
+         (close-quote (if lang (nth 2 lang) TeX-close-quote))
+         (q-after-q (if lang (nth 3 lang) TeX-quote-after-quote)))
+    (when (functionp open-quote)
+      (setq open-quote (funcall open-quote)))
+    (when (functionp close-quote)
+      (setq close-quote (funcall close-quote)))
+    (list open-quote close-quote q-after-q)))
+
 ;; TODO: rework according to the slogan from
 ;; `TeX--put-electric-delete-selection'. That entails splitting off the
 ;; «electric» part that tries to do smart things and the plain part that
@@ -6411,18 +6429,8 @@ With prefix argument FORCE, always inserts \" 
characters."
           (and (TeX-in-comment) (not (eq major-mode 'docTeX-mode))))
       (self-insert-command (prefix-numeric-value force))
     (TeX-update-style)
-    (let* ((lang-override (if (eq (car TeX-quote-language) 'override)
-                              TeX-quote-language
-                            (assoc (car TeX-quote-language)
-                                   TeX-quote-language-alist)))
-           (lang (or lang-override TeX-quote-language))
-           (open-quote (if lang (nth 1 lang) TeX-open-quote))
-           (close-quote (if lang (nth 2 lang) TeX-close-quote))
-           (q-after-q (if lang (nth 3 lang) TeX-quote-after-quote)))
-      (when (functionp open-quote)
-        (setq open-quote (funcall open-quote)))
-      (when (functionp close-quote)
-        (setq close-quote (funcall close-quote)))
+    (pcase-let ((`(,open-quote ,close-quote ,q-after-q)
+                 (TeX-get-quote-characters)))
       (if q-after-q
           (insert (cond ((bobp)
                          ?\")
@@ -6473,7 +6481,28 @@ With prefix argument FORCE, always inserts \" 
characters."
                          (looking-at "[ \t\n]\\|\\s("))
                        open-quote)
                       (t
-                       close-quote)))))))
+                       close-quote))))
+      ;; Fold quotes if TeX-fold-quotes-on-insert is t
+      (when (and (boundp 'TeX-fold-mode)
+                 (boundp 'TeX-fold-quotes-on-insert)
+                 (fboundp 'TeX-fold-quotes)
+                 TeX-fold-mode
+                 TeX-fold-quotes-on-insert
+                 (not (eq (char-before) ?\")))  ; Don't fold single quotes
+        (save-excursion
+          (let* ((end (point))
+                 (start (- end
+                           (length
+                            (if (string= (buffer-substring-no-properties
+                                          (max (point-min)
+                                               (- end (length open-quote)))
+                                          end)
+                                         open-quote)
+                                open-quote
+                              close-quote)))))
+            (when start
+              (TeX-fold-quotes start end))))))))
+
 
 (put 'TeX-insert-quote 'delete-selection t)