is it easy to make line numbering start at 0 too?

is it easy to make line numbering start at 0 too?

[Christian Seberino]

is it easy to make line numbering start at 0 too?

Re: is it easy to make line numbering start at 0 too?

[John Paul Wallington]

seberino@spawar.navy.mil (Christian Seberino) wrote:

> is it easy to make line numbering start at 0 too?

If you mean in the modeline, the best bet is probably to hack the
decode_mode_spec in xdisp.c:

[caveats: I don't grok C, and the doc-string format is different for
released versions of Emacs.]

Index: xdisp.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/xdisp.c,v
retrieving revision 1.798
diff -u -r1.798 xdisp.c
--- xdisp.c	6 Jan 2003 00:58:45 -0000	1.798
+++ xdisp.c	9 Jan 2003 11:31:41 -0000
@@ -464,6 +464,14 @@
 
 int cursor_type_changed;
 
+/* Nonzero means column number display starts at one */
+
+int column_number_start_at_one;
+
+/* Nonzero means line number display starts at one */
+
+int line_number_start_at_one;
+
 /* Nonzero after display_mode_line if %l was used and it displayed a
    line number.  */
 
@@ -14625,6 +14633,8 @@
       {
 	int col = (int) current_column (); /* iftc */
 	w->column_number_displayed = make_number (col);
+	if (column_number_start_at_one)
+	  ++col;
 	pint2str (decode_mode_spec_buf, field_width, col);
 	return decode_mode_spec_buf;
       }
@@ -14732,6 +14742,8 @@
 	/* Now count lines from the start pos to point.  */
 	nlines = display_count_lines (startpos, startpos_byte,
 				      PT_BYTE, PT, &junk);
+	if (!line_number_start_at_one)
+	  --nlines;
 
 	/* Record that we did display the line number.  */
 	line_number_displayed = 1;
@@ -15663,6 +15675,14 @@
 Any other value means to use the appropriate face, `mode-line',
 `header-line', or `menu' respectively.  */);
   mode_line_inverse_video = 1;
+
+  DEFVAR_BOOL ("column-number-start-at-one", &column_number_start_at_one,
+    doc: /* *Non-nil means column number display starts at one.  */);
+  column_number_start_at_one = 0;
+
+  DEFVAR_BOOL ("line-number-start-at-one", &line_number_start_at_one,
+    doc: /* *Non-nil means line number display starts at one.  */);
+  line_number_start_at_one = 1;
 
   DEFVAR_LISP ("line-number-display-limit", &Vline_number_display_limit,
     doc: /* *Maximum buffer size for which line number should be displayed.

-- 
John Paul Wallington

Re: is it easy to make line numbering start at 0 too?

[Rikard Bosnjakovic]

> is it easy to make line numbering start at 0 too?

?


-- 
Friendly,

Rikard

Re: is it easy to make line numbering start at 0 too?

[Benjamin Lewis]

Christian Seberino wrote:

> is it easy to make line numbering start at 0 too?

Not sure exactly what your asking, but keep in mind that column-numbering
and line-numbering have a fundamental difference:  when the cursor is on
the top-left position in the buffer, point is *on* the first line but
*before* the first character.  Think of point as a line that has zero
width, but the height of a line of text.

-- 
Benjamin Lewis

Don't take life so serious, son, it ain't nohow permanent.
                -- Walt Kelly

Re: is it easy to make line numbering start at 0 too?

[Henrik Enberg]

seberino@spawar.navy.mil (Christian Seberino) writes:

> is it easy to make line numbering start at 0 too?

No.  It is hardcoded on the C level.

Re: is it easy to make line numbering start at 0 too?

[John Paul Wallington]

seberino@spawar.navy.mil wrote:

> Thanks for the reply! This is a very cool way to do
> the modeline modification.... I originally made column numbering
> on modeline start at 1 this way....
[...]
>   (setq default-mode-line-format
[...]
>            '(:eval (format "%d" (1+ (current-column))))))
>   (add-hook 'post-command-hook (lambda () (force-mode-line-update)))

> This has side effects... it messed up scroll-step behavior... this is
> why I need a new way.

> A problem with hacking Emacs source code is that I can't
> make these changes happen on remote machines that I don't have root
> privileges on.
>
> Plus, it sounds like new Emacs versions may not be compatible
> with changes. 

Hacking decode_mode_spec in xdisp.c as mentioned earlier is much more
straightforward than trying to replicate the same effect in emacs
lisp.  XEmacs has a `column-number-start-at-one' builtin and heeds it.
If there is a genuine demand for the functionality you should propose
it to the Emacs maintainers; as demonstrated it is a simple addition.

It is controversial because presently the column and line number
displays on the modeline reflect `point' which is on a line and
between characters.  The question arises as to why a user wants Emacs
to tell fibs about column/line numbers; what is wrong with column
numbers starting at zero, and line numbers at one?

-- 
John Paul Wallington