Implement 1-based column numbering in mode line

* src/xdisp.c (decode_mode_spec): Implement the %C construct.

* lisp/bindings.el (column-number-indicator-zero-based): New
defcustom.
(mode-line-position): Use %C when
column-number-indicator-zero-based is nil.

* src/xdisp.c (syms_of_xdisp) <frame-title-format>:
* src/buffer.c (syms_of_buffer) <mode-line-format>:
* doc/lispref/modes.texi (%-Constructs):
* doc/lispref/frames.texi (Frame Titles): Document the %C
construct.

* doc/emacs/display.texi (Optional Mode Line): Document
'column-number-indicator-zero-based'.

* etc/NEWS: Mention 'column-number-indicator-zero-based' and the
%C construct.

diff --git a/doc/emacs/display.texi b/doc/emacs/display.texi
index 15c700892bcaab62caa849e63658f8fc009c8bee..d07913cefbea7ef93d3e34e5590528837c031263 100644 (file)
--- a/doc/emacs/display.texi
+++ b/doc/emacs/display.texi
@@ -1338,13 +1338,19 @@ indicate what it is.
 @cindex mode, Column Number
 @findex column-number-mode
   Similarly, you can display the current column number by turning on
-Column number mode with @kbd{M-x column-number-mode}.  The column
+Column Number mode with @kbd{M-x column-number-mode}.  The column
 number is indicated by the letter @samp{C}.  However, when both of
 these modes are enabled, the line and column numbers are displayed in
 parentheses, the line number first, rather than with @samp{L} and
 @samp{C}.  For example: @samp{(561,2)}.  @xref{Minor Modes}, for more
 information about minor modes and about how to use these commands.
 
+@vindex column-number-indicator-zero-based
+  In Column Number mode, the displayed column number counts from zero
+starting at the left margin of the window.  If you would prefer for
+the displayed column number to count from one, you may set
+@code{column-number-indicator-zero-based} to @code{nil}.
+
 @cindex narrowing, and line number display
   If you have narrowed the buffer (@pxref{Narrowing}), the displayed
 line number is relative to the accessible portion of the buffer.

diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index bed7873fe3ff2ec629387483589c35694a9deb5f..fc7956d12e35d5cee72b6f18892797972a32e680 100644 (file)
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -2239,7 +2239,7 @@ frame is redisplayed.
 This variable specifies how to compute a name for a frame when you have
 not explicitly specified one.  The variable's value is actually a mode
 line construct, just like @code{mode-line-format}, except that the
-@samp{%c} and @samp{%l} constructs are ignored.  @xref{Mode Line
+@samp{%c}, @samp{%C}, and @samp{%l} constructs are ignored.  @xref{Mode Line
 Data}.
 @end defvar
 

diff --git a/doc/lispref/modes.texi b/doc/lispref/modes.texi
index 2e7d769f93d09c33136f312416ac5d39a2a8052e..eb72fcfd36917389672eb2dedf9940f93b901027 100644 (file)
--- a/doc/lispref/modes.texi
+++ b/doc/lispref/modes.texi
@@ -2111,7 +2111,12 @@ The current buffer name, obtained with the @code{buffer-name} function.
 @xref{Buffer Names}.
 
 @item %c
-The current column number of point.
+The current column number of point, counting from zero starting at the
+left margin of the window.
+
+@item %C
+The current column number of point, counting from one starting at the
+left margin of the window.
 
 @item %e
 When Emacs is nearly out of memory for Lisp objects, a brief message

diff --git a/etc/NEWS b/etc/NEWS
index 4c0f4d2904f9810571c61ebe5dbfc6616c2d9b94..3b830c934249777efc1443c36e1b0bc1bdfec6a2 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -341,6 +341,16 @@ suppresses display of return values from the server process.
 \f
 * Editing Changes in Emacs 26.1
 
++++
+** New variable 'column-number-indicator-zero-based'.
+Traditionally, in Column Number mode, the displayed column number
+counts from zero starting at the left margin of the window.  This
+behavior is now controlled by 'column-number-indicator-zero-based'.
+If you would prefer for the displayed column number to count from one,
+you may set this variable to nil.  (Behind the scenes, there is now a
+new mode line construct, '%C', which operates exactly as '%c' does
+except that it counts from one.)
+
 +++
 ** Two new user options 'list-matching-lines-jump-to-current-line' and
 'list-matching-lines-current-line-face' to show highlighted the current

diff --git a/lisp/bindings.el b/lisp/bindings.el
index a77fd4d599a0df8a20d96cfc7739991aa71e3de1..85a54087178c5296f53924acb12270c3b88523c5 100644 (file)
--- a/lisp/bindings.el
+++ b/lisp/bindings.el
@@ -354,6 +354,17 @@ mouse-3: Toggle minor modes"
     map) "\
 Keymap to display on column and line numbers.")
 
+(defcustom column-number-indicator-zero-based t
+  "When non-nil, mode line displays column numbers zero-based.
+
+This variable has effect only when Column Number mode is turned on,
+which displays column numbers in the mode line.
+If the value is non-nil, the displayed column numbers start from
+zero, otherwise they start from one."
+  :type 'boolean
+  :group 'mode-line
+  :version "26.1")
+
 (defvar mode-line-position
   `((-3 ,(propertize
          "%p"
@@ -372,12 +383,19 @@ mouse-1: Display Line and Column Mode Menu"))
 mouse-1: Display Line and Column Mode Menu")))
     (line-number-mode
      ((column-number-mode
-       (10 ,(propertize
-            " (%l,%c)"
-            'local-map mode-line-column-line-number-mode-map
-            'mouse-face 'mode-line-highlight
-            'help-echo "Line number and Column number\n\
+       (column-number-indicator-zero-based
+        (10 ,(propertize
+              " (%l,%c)"
+              'local-map mode-line-column-line-number-mode-map
+              'mouse-face 'mode-line-highlight
+              'help-echo "Line number and Column number\n\
 mouse-1: Display Line and Column Mode Menu"))
+        (10 ,(propertize
+              " (%l,%C)"
+              'local-map mode-line-column-line-number-mode-map
+              'mouse-face 'mode-line-highlight
+              'help-echo "Line number and Column number\n\
+mouse-1: Display Line and Column Mode Menu")))
        (6 ,(propertize
            " L%l"
            'local-map mode-line-column-line-number-mode-map
@@ -385,12 +403,19 @@ mouse-1: Display Line and Column Mode Menu"))
            'help-echo "Line Number\n\
 mouse-1: Display Line and Column Mode Menu"))))
      ((column-number-mode
-       (5 ,(propertize
-           " C%c"
-           'local-map mode-line-column-line-number-mode-map
-           'mouse-face 'mode-line-highlight
-           'help-echo "Column number\n\
-mouse-1: Display Line and Column Mode Menu"))))))
+       (column-number-indicator-zero-based
+        (5 ,(propertize
+             " C%c"
+             'local-map mode-line-column-line-number-mode-map
+             'mouse-face 'mode-line-highlight
+             'help-echo "Column number\n\
+mouse-1: Display Line and Column Mode Menu"))
+        (5 ,(propertize
+             " C%C"
+             'local-map mode-line-column-line-number-mode-map
+             'mouse-face 'mode-line-highlight
+             'help-echo "Column number\n\
+mouse-1: Display Line and Column Mode Menu")))))))
   "Mode line construct for displaying the position in the buffer.
 Normally displays the buffer percentage and, optionally, the
 buffer size, the line number and the column number.")

diff --git a/src/buffer.c b/src/buffer.c
index 33ffdf8eb8edced35d6e4c94c2b38897af1fde2f..80dbd3318dc06380dc6cd09cf5db03d5670bee48 100644 (file)
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -5486,8 +5486,11 @@ A string is printed verbatim in the mode line except for %-constructs:
        For a modified read-only buffer, %* gives % and %+ gives *.
   %s -- print process status.   %l -- print the current line number.
   %c -- print the current column number (this makes editing slower).
+        Columns are numbered starting from the left margin, and the
+        leftmost column is displayed as zero.
         To make the column number update correctly in all cases,
        `column-number-mode' must be non-nil.
+  %C -- Like %c, but the leftmost column is displayed as one.
   %i -- print the size of the buffer.
   %I -- like %i, but use k, M, G, etc., to abbreviate.
   %p -- print percent of buffer above top of window, or Top, Bot or All.

diff --git a/src/xdisp.c b/src/xdisp.c
index c730cdae05478eabc18e049abbba85e96fa05bb1..cdea20993c733a27928706d39276327b1b81d4f8 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -476,7 +476,7 @@ int windows_or_buffers_changed;
    used to track down the cause for this full-redisplay).
 
    Since the frame title uses the same %-constructs as the mode line
-   (except %c and %l), if this variable is non-zero, we also consider
+   (except %c, %C, and %l), if this variable is non-zero, we also consider
    redisplaying the title of each frame, see x_consider_frame_title.
 
    The `redisplay' bits are the same as those used for
@@ -11530,7 +11530,7 @@ window_buffer_changed (struct window *w)
   return (BUF_SAVE_MODIFF (b) < BUF_MODIFF (b)) != w->last_had_star;
 }
 
-/* True if W has %c in its mode line and mode line should be updated.  */
+/* True if W has %c or %C in its mode line and mode line should be updated.  */
 
 static bool
 mode_line_update_needed (struct window *w)
@@ -23690,7 +23690,8 @@ decode_mode_spec (struct window *w, register int c, int field_width,
       break;
 
     case 'c':
-      /* %c and %l are ignored in `frame-title-format'.
+    case 'C':
+      /* %c, %C, and %l are ignored in `frame-title-format'.
          (In redisplay_internal, the frame title is drawn _before_ the
          windows are updated, so the stuff which depends on actual
          window contents (such as %l) may fail to render properly, or
@@ -23700,8 +23701,9 @@ decode_mode_spec (struct window *w, register int c, int field_width,
       else
        {
          ptrdiff_t col = current_column ();
+         int disp_col = (c == 'C') ? col + 1 : col;
          w->column_number_displayed = col;
-         pint2str (decode_mode_spec_buf, width, col);
+         pint2str (decode_mode_spec_buf, width, disp_col);
          return decode_mode_spec_buf;
        }
 
@@ -23749,7 +23751,7 @@ decode_mode_spec (struct window *w, register int c, int field_width,
        ptrdiff_t topline, nlines, height;
        ptrdiff_t junk;
 
-       /* %c and %l are ignored in `frame-title-format'.  */
+       /* %c, %C, and %l are ignored in `frame-title-format'.  */
        if (mode_line_target == MODE_LINE_TITLE)
          return "";
 
@@ -31725,7 +31727,7 @@ This variable is not guaranteed to be accurate except while processing
 \(Assuming the window manager supports this feature.)
 
 This variable has the same structure as `mode-line-format', except that
-the %c and %l constructs are ignored.  It is used only on frames for
+the %c, %C, and %l constructs are ignored.  It is used only on frames for
 which no explicit name has been set (see `modify-frame-parameters').  */);
 
   DEFVAR_LISP ("icon-title-format", Vicon_title_format,