[elpa] externals/indent-bars e35c54e16d 038/431: blank-lines: improve extend and mark algorithm

[ELPA Syncer]

branch: externals/indent-bars
commit e35c54e16d72e80201a862437b93776b86cf52bc
Author: JD Smith <93749+jdtsmith@users.noreply.github.com>
Commit: JD Smith <93749+jdtsmith@users.noreply.github.com>

    blank-lines: improve extend and mark algorithm
---
 indent-bars.el | 83 +++++++++++++++++++++++++++++++---------------------------
 1 file changed, 45 insertions(+), 38 deletions(-)

diff --git a/indent-bars.el b/indent-bars.el
index a8d6b1167e..3eef878698 100644
--- a/indent-bars.el
+++ b/indent-bars.el
@@ -627,19 +627,19 @@ OBJ, otherwise in the buffer.  OBJ is returned."
 (defvar font-lock-beg) (defvar font-lock-end) ; Dynamic font-lock variables!
 (defun indent-bars--extend-blank-line-regions ()
   "Extend the region about to be font-locked to include stretches of blank 
lines."
+  ;; (message "request to extend: %d->%d" font-lock-beg font-lock-end)
   (let ((changed nil) (chars " \n"))
-    (unless (eq font-lock-beg (point-min))
-      (goto-char (1- font-lock-beg))
-      (when (< (skip-chars-backward chars) 0)
-       (unless (bolp) (beginning-of-line 2)) ; spaces at end don't count
-       (if (< (point) font-lock-beg)
-           (setq changed t font-lock-beg (point)))))
-    (unless (eq font-lock-end (point-max))
-      (goto-char (1+ font-lock-end))
-      (when (> (skip-chars-forward chars) 0)
-       ;; (unless (eolp) (beginning-of-line 0))
-       (if (> (point) font-lock-end)
-           (setq changed t font-lock-end (point)))))
+    (goto-char font-lock-beg)
+    (when (< (skip-chars-backward chars) 0)
+      (unless (bolp) (beginning-of-line 2)) ; spaces at end don't count
+      (when (< (point) font-lock-beg)
+       (setq changed t font-lock-beg (point))))
+    (goto-char font-lock-end)
+    (when (> (skip-chars-forward chars) 0)
+      (unless (bolp) (beginning-of-line 1))
+      (when (> (point) font-lock-end)
+       (setq changed t font-lock-end (point))))
+    ;; (if changed (message "expanded to %d->%d" font-lock-beg font-lock-end))
     changed))
 
 (defun indent-bars--handle-blank-lines ()
@@ -649,35 +649,42 @@ is non-nil.  Uses surrounding line indentation to 
determine
 additional bars to display on each line, and uses a string
 display property on the final newline if necessary to display the
 needed bars.  Blank lines at the beginning or end of the buffer
-are not indicated."
+are not indicated, even if otherwise they would be."
   (let* ((beg (match-beginning 0))
         (end (match-end 0))
         ctxbars)
-    (when (and (not (= end (point-max))) (not (= beg (point-min))))
-      (goto-char beg)
-      (forward-line -1)
-      (when (> (setq ctxbars
-                    (1- (max (/ (current-indentation) indent-bars-spacing)
-                             (progn
-                               (goto-char end)
-                               (forward-line 1)
-                               (/ (current-indentation) 
indent-bars-spacing)))))
-              0)
-       (goto-char beg)
-       (while (< (point) end)
-        (let* ((bp (line-beginning-position))
-               (ep (line-end-position))
-               (len (- ep bp))
-               (nbars (/ len indent-bars-spacing))
-               nsp off s) ; "natural" bars
-          (if (> nbars 0) (indent-bars--draw bp ep))
-          (when (> ctxbars nbars) ;we need more bars than we have space!
-            (unless (and (eq off (setq off (- (* (1+ nbars) 
indent-bars-spacing) len)))
-                         (eq nsp (setq nsp (- (* ctxbars indent-bars-spacing) 
len))))
-              (setq s (concat (make-string nsp ?\s) "\n"))
-              (indent-bars--draw off nsp (1+ nbars) s))
-            (set-text-properties ep (1+ ep) `(display ,s)))
-          (forward-line 1)))))))
+    (when (and (/= end (point-max)) (/= beg (point-min)))
+      (save-excursion
+       ;; (message "BL: %d[%d]->%d[%d]" beg (/ (current-indentation) 
indent-bars-spacing)
+       ;;       end
+       ;;       (progn
+       ;;         (goto-char end)
+       ;;         (/ (current-indentation) indent-bars-spacing)))
+       (goto-char (1- beg))            ;beg always bol
+       (when (> (setq ctxbars
+                      (1- (max (/ (current-indentation) indent-bars-spacing)
+                               (progn
+                                 (goto-char (1+ end)) ; end always eol
+                                 (/ (current-indentation) 
indent-bars-spacing)))))
+                0)
+         (goto-char beg)
+         (while (<= (point) end)
+           (let* ((bp (line-beginning-position))
+                  (ep (line-end-position))
+                  (len (- ep bp))
+                  (nbars (/ (max 0 (1- len)) indent-bars-spacing)))
+             ;; (message "len: %d nbars: %d ctxbars:%d" len nbars ctxbars)
+             ;; Draw "real" bars in existing blank
+             (if (> nbars 0) (indent-bars--draw (+ bp indent-bars-spacing) ep))
+             ;; Add fake bars via display
+             (when (> ctxbars nbars) 
+               (let* ((off (- (* (1+ nbars) indent-bars-spacing) len))
+                      (nsp (1+ (- (* ctxbars indent-bars-spacing) len)))
+                      (s (concat (make-string nsp ?\s) "\n")))
+                 (indent-bars--draw off nsp (1+ nbars) s)
+                 (put-text-property ep (1+ ep) 'display s)))
+             (beginning-of-line 2)))))
+      nil)))
 
 ;;;; Current indentation highlight
 (defvar-local indent-bars--current-depth 0)