When working my way through source code files, I sometimes notice myself
starting to wonder how long it'll be before my plight is over. Hitting
control-G over and over again increases anxiety. Instead, the ruler
could just show, as a percentage, how far into the file the cursor is.

This patch adds an 'are we there yet?' signal in the column bar by means
of displaying the current line number as a percentage of the total lines
in the file, only if the 'ruler' option is set, and if the last line
number can be determined.

OK?

Index: docs/USD.doc/vi.man/vi.1
===================================================================
RCS file: /cvs/src/usr.bin/vi/docs/USD.doc/vi.man/vi.1,v
diff -u -p -r1.84 vi.1
--- docs/USD.doc/vi.man/vi.1	12 Feb 2024 16:42:42 -0000	1.84
+++ docs/USD.doc/vi.man/vi.1	21 Apr 2024 22:12:29 -0000
@@ -2461,7 +2461,7 @@ Set the number of lines about which the 
 .It Cm ruler Bq off
 .Nm vi
 only.
-Display a row/column ruler on the colon command line.
+Display a row/column/percentage ruler on the colon command line.
 .It Cm scroll , scr Bq "($LINES \- 1) / 2"
 Set the number of lines scrolled.
 .It Cm searchincr Bq off
Index: vi/vs_refresh.c
===================================================================
RCS file: /cvs/src/usr.bin/vi/vi/vs_refresh.c,v
diff -u -p -r1.23 vs_refresh.c
--- vi/vs_refresh.c	12 Feb 2024 16:42:43 -0000	1.23
+++ vi/vs_refresh.c	21 Apr 2024 22:12:29 -0000
@@ -782,6 +782,7 @@ vs_modeline(SCR *sp)
 	const char *t = NULL;
 	int ellipsis;
 	char *p, buf[20];
+	recno_t last;
 
 	/*
 	 * It's possible that this routine will be called after sp->frp
@@ -857,8 +858,14 @@ vs_modeline(SCR *sp)
 	cols = sp->cols - 1;
 	if (O_ISSET(sp, O_RULER)) {
 		vs_column(sp, &curcol);
-		len = snprintf(buf, sizeof(buf), "%lu,%zu",
-		    (ulong)sp->lno, curcol + 1);
+
+		if (db_last(sp, &last))
+			len = snprintf(buf, sizeof(buf), "%lu,%zu",
+			    (ulong)sp->lno, curcol + 1);
+		else
+			len = snprintf(buf, sizeof(buf), "%lu,%zu %lu%%",
+			    (ulong)sp->lno, curcol + 1,
+			    (unsigned long)(sp->lno * 100) / last);
 
 		midpoint = (cols - ((len + 1) / 2)) / 2;
 		if (curlen < midpoint) {