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:
> What about something like this: 
> 
>     (defun current-line (&optional ignore-narrowing) 
>       ...) 

thanks for your suggestion. I applied it in attached patch. I'm 
not sure I like it though because the simplest call:

    (current-line)

is now exactly the same as (line-number-at-pos). To get a 
different behavior, non-nil must be passed as argument:

    (current-line t)

Nevertheless, I understand this implementation is probably the one 
closest to existing API and usages.

Best,

-- 
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 727955fb2a063117b464309b6303cb270d91b71b 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            |  9 +++++++++
 test/lisp/simple-tests.el | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/lisp/simple.el b/lisp/simple.el
index edc822e..becbb6c 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -1283,6 +1283,15 @@ (defun line-number-at-pos (&optional pos)
       (forward-line 0)
       (1+ (count-lines start (point))))))
 
+(defun current-line (&optional ignore-narrowing)
+  "Return line number at point.
+If IGNORE-NARROWING is not-nil, return the absolute line number."
+  (if (not ignore-narrowing)
+      (line-number-at-pos (point))
+    (save-restriction
+      (widen)
+      (line-number-at-pos (point)))))
+
 (defun what-cursor-position (&optional detail)
   "Print info on cursor position (on screen and within buffer).
 Also describe the character after point, and give its character code
diff --git a/test/lisp/simple-tests.el b/test/lisp/simple-tests.el
index f4849c4..5b00d0c 100644
--- a/test/lisp/simple-tests.el
+++ b/test/lisp/simple-tests.el
@@ -374,5 +374,46 @@ (ert-deftest missing-record-point-in-undo ()
        (undo)
        (point)))))
 
+(ert-deftest current-line-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 (current-line) target-line))
+      (should (equal (current-line t) target-line)))))
+
+(ert-deftest current-line-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 (current-line) 1))
+      (should (equal (current-line t) target-line)))))
+
+(ert-deftest current-line-keeps-restriction ()
+  (let (pos)
+    (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))
+      (current-line t)
+      (should (equal (line-number-at-pos) 1)))))
+
+(ert-deftest current-line-keeps-point ()
+  (let (pos)
+    (with-temp-buffer
+      (insert "a\nb\nc\nd\n")
+      (goto-char (point-min))
+      (forward-line 2)
+      (setq pos (point))
+      (current-line)
+      (current-line t)
+      (should (equal pos (point))))))
+
 (provide 'simple-test)
 ;;; simple-test.el ends here
-- 
2.9.3