bug#26417: 25.2; Add current-line in simple.el

[Damien Cassou <damien@cassou.me>]

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Nicolas Petton <nicolas@petton.fr> writes:
> Indeed.  What about adding the optional argument to 
> `line-number-at-pos' then? 

ok. Here is another version following your piece of advice. 

-- 
Damien Cassou
http://damiencassou.seasidehosting.st

"Success is the ability to go from one failure to another without
losing enthusiasm." --Winston Churchill

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From f613a3c9c4219220e164b7c326a8064f1ec25656 Mon Sep 17 00:00:00 2001
From: Damien Cassou <damien@cassou.me>
Date: Sun, 9 Apr 2017 12:46:57 +0200
Subject: [PATCH] Add current-line in simple.el

* lisp/simple.el (current-line): New function.
* test/list/simple-tests.el: Add tests for current-line.
---
 lisp/simple.el            | 29 +++++++++++++++++-----------
 test/lisp/simple-tests.el | 49 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 11 deletions(-)

diff --git a/lisp/simple.el b/lisp/simple.el
index ea3a495..e836018 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -1270,18 +1270,25 @@ (defun count-lines (start end)
 		done)))
 	(- (buffer-size) (forward-line (buffer-size)))))))
 
-(defun line-number-at-pos (&optional pos)
-  "Return (narrowed) buffer line number at position POS.
+(defun line-number-at-pos (&optional pos absolute-p)
+  "Return buffer line number at position POS.
 If POS is nil, use current buffer location.
-Counting starts at (point-min), so the value refers
-to the contents of the accessible portion of the buffer."
-  (let ((opoint (or pos (point))) start)
-    (save-excursion
-      (goto-char (point-min))
-      (setq start (point))
-      (goto-char opoint)
-      (forward-line 0)
-      (1+ (count-lines start (point))))))
+
+If ABSOLUTE-P is nil, the default, counting starts
+at (point-min), so the value refers to the contents of the
+accessible portion of the (potentially narrowed) buffer.  If
+ABSOLUTE-P is non-nil, ignore any narrowing and return the
+absolute line number."
+  (save-restriction
+    (when absolute-p
+      (widen))
+    (let ((opoint (or pos (point))) start)
+      (save-excursion
+        (goto-char (point-min))
+        (setq start (point))
+        (goto-char opoint)
+        (forward-line 0)
+        (1+ (count-lines start (point)))))))
 
 (defun what-cursor-position (&optional detail)
   "Print info on cursor position (on screen and within buffer).
diff --git a/test/lisp/simple-tests.el b/test/lisp/simple-tests.el
index 180dcc0..ad7aee1 100644
--- a/test/lisp/simple-tests.el
+++ b/test/lisp/simple-tests.el
@@ -448,5 +448,54 @@ (ert-deftest eval-expression-print-format-large-int-echo ()
         (call-interactively #'eval-expression)
         (should (equal (current-message) "66 (#o102, #x42, ?B)"))))))
 
+(ert-deftest line-number-at-pos-in-widen-buffer ()
+  (let ((target-line 3))
+    (with-temp-buffer
+      (insert "a\nb\nc\nd\n")
+      (goto-char (point-min))
+      (forward-line (1- target-line))
+      (should (equal (line-number-at-pos) target-line))
+      (should (equal (line-number-at-pos nil t) target-line)))))
+
+(ert-deftest line-number-at-pos-in-narrow-buffer ()
+  (let ((target-line 3))
+    (with-temp-buffer
+      (insert "a\nb\nc\nd\n")
+      (goto-char (point-min))
+      (forward-line (1- target-line))
+      (narrow-to-region (line-beginning-position) (line-end-position))
+      (should (equal (line-number-at-pos) 1))
+      (should (equal (line-number-at-pos nil t) target-line)))))
+
+(ert-deftest line-number-at-pos-keeps-restriction ()
+  (with-temp-buffer
+    (insert "a\nb\nc\nd\n")
+    (goto-char (point-min))
+    (forward-line 2)
+    (narrow-to-region (line-beginning-position) (line-end-position))
+    (should (equal (line-number-at-pos) 1))
+    (line-number-at-pos nil t)
+    (should (equal (line-number-at-pos) 1))))
+
+(ert-deftest line-number-at-pos-keeps-point ()
+  (let (pos)
+    (with-temp-buffer
+      (insert "a\nb\nc\nd\n")
+      (goto-char (point-min))
+      (forward-line 2)
+      (setq pos (point))
+      (line-number-at-pos)
+      (line-number-at-pos nil t)
+      (should (equal pos (point))))))
+
+(ert-deftest line-number-at-pos-when-passing-point ()
+  (let (pos)
+    (with-temp-buffer
+      (insert "a\nb\nc\nd\n")
+      (should (equal (line-number-at-pos 1) 1))
+      (should (equal (line-number-at-pos 3) 2))
+      (should (equal (line-number-at-pos 5) 3))
+      (should (equal (line-number-at-pos 7) 4)))))
+
 (provide 'simple-test)
 ;;; simple-test.el ends here
-- 
2.9.4