text-conf: Clean up and new durand-elide-region command

* text-conf.el (correct-length): Obsolete now.

(center-string-in-width): Use string-width.

(durand-elide-region, text-mode-map): New command to elide a region of
texts.

1 files changed, 43 insertions, 5 deletions

diff --git a/text-conf.el b/text-conf.el
index bbd49e9..ad0d78f 100644
--- a/text-conf.el
+++ b/text-conf.el
@@ -9,6 +9,8 @@
 
 ;; (define-key text-mode-map (vector 'f8) nil)
 
+;;; Insert section heading
+
 ;;;###autoload
 (defvar insert-section-heading-history nil
   "The history of inserted section heading strings")
@@ -47,12 +49,15 @@ exactly the current ilne."
         (setq index (1+ index)))
       (insert remainder-string))))
 
+;;; Center text
+
 ;;;###autoload
 (defun correct-length (str)
   "Return the length of STR.
 Characters that take up more than one column will be counted with
 1.7 columns."
-  (declare (side-effect-free t) (pure t))
+  (declare (side-effect-free t) (pure t)
+           (obsolete string-width "2021-12-21 20:56:10.928712"))
   (let ((len 0))
     (mapc (lambda (char)
             (let ((name (get-char-code-property char 'name))
@@ -70,8 +75,9 @@ Characters that take up more than one column will be counted with
 
 ;;;###autoload
 (defun center-string-in-width (str width)
-  "Add spaces to STR so that it is centered in a box which is WIDTH wide."
-  (let ((len (correct-length str)))
+  "Add spaces to STR so that it is centered in a box which is WIDTH \
+wide."
+  (let ((len (string-width str)))
     (cond
      ((> len width)
       (error "String %s longer than %d" str width))
@@ -80,6 +86,8 @@ Characters that take up more than one column will be counted with
                              32)
                 str)))))
 
+;;; Make a block
+
 ;;;###autoload
 (defvar make-block-history nil
   "The history of block quote descriptions.")
@@ -125,6 +133,8 @@ DESCRIPTION above the block."
       (newline)
       (insert fill-line))))
 
+;;; Moving between pages
+
 ;;;###autoload
 (defun durand-next-page (&optional arg)
   "Move forward ARG pages and narrow to page.
@@ -145,7 +155,7 @@ Pass (- (prefix-numeric-value arg)) to `durand-next-page'."
 (define-key text-mode-map (vector ?\s-m) #'durand-previous-page)
 (define-key text-mode-map (vector ?\s-ù) #'durand-next-page)
 
-;; Insert time stamps
+;;; Insert time stamps
 
 ;;;###autoload
 (defun durand-insert-timestamp (&optional arg)
@@ -158,7 +168,7 @@ If ARG is non-nil, use a more verbose format."
 
 (define-key global-map (vector ?\H-=) #'durand-insert-timestamp)
 
-;; a diff-dwim
+;;; a diff-dwim
 
 (autoload 'vc-diff "vc.el")
 
@@ -181,5 +191,33 @@ If ARG is non-nil, use a more verbose format."
 
 (define-key global-map (vector ?\C-\M-=) #'durand-diff-dwim)
 
+;;; Eliding a region of text
+
+(defun durand-elide-region (beg end ignore-invisible-lines)
+  "Elide a region of text delimited by BEG and END.
+If IGNORE-INVISIBLE-LINES is non-nil, the line count will not
+include invisible lines."
+  (interactive
+   (cond
+    ((use-region-p) (list (region-beginning) (region-end)
+                          current-prefix-arg))
+    ((user-error "First select a region to elide"))))
+  (cond
+   ((> beg end)
+    (let ((temp beg))
+      (setq beg end) (setq end temp))))
+  (setq beg (save-excursion
+              (goto-char beg)
+              (line-beginning-position)))
+  (setq end (save-excursion
+              (goto-char end)
+              (line-end-position)))
+  (let ((n (count-lines beg end ignore-invisible-lines)))
+    (save-excursion
+      (delete-region beg end)
+      (insert (format "    >> [ %d lines elided ... ]" n)))))
+
+(define-key text-mode-map (vector ?\M-\s-\=) #'durand-elide-region)
+
 (provide 'text-conf)
 ;;; text-conf.el ends here.