Delete what remains of the support for combining characters into

ligatures: it was incomplete (only for the Arabic script and only
for the single ligature LAM WITH ALEF) and it was implemented in a
way that is unsustainable (with a static table inside less).

If we ever want ligature support, we are better off making a fresh
start.  However, for languages like Arabic and Persian, even that
wouldn't really be useful without having bidirectional support first.

OK millert@
(and also considering comments from Mohammadreza Abdollahzadeh,
Evan Silberman, and benno@)

4 files changed, 7 insertions, 42 deletions

diff --git a/usr.bin/less/charset.c b/usr.bin/less/charset.c
index 5739fe1b71a..3090dea6364 100644
--- a/usr.bin/less/charset.c
+++ b/usr.bin/less/charset.c
@@ -474,13 +474,6 @@ static struct wchar_range comp_table[] = {
 };
 
 /*
- * Special pairs, not ranges.
- */
-static struct wchar_range comb_table[] = {
-	{0x0644, 0x0622}, {0x0644, 0x0623}, {0x0644, 0x0625}, {0x0644, 0x0627},
-};
-
-/*
  * Characters with general category values
  *	Cc: Other, Control
  *	Cf: Other, Format
@@ -826,21 +819,3 @@ is_wide_char(LWCHAR ch)
 	return (is_in_table(ch, wide_table,
 	    (sizeof (wide_table) / sizeof (*wide_table))));
 }
-
-/*
- * Is a character a UTF-8 combining character?
- * A combining char acts like an ordinary char, but if it follows
- * a specific char (not any char), the two combine into one glyph.
- */
-int
-is_combining_char(LWCHAR ch1, LWCHAR ch2)
-{
-	/* The table is small; use linear search. */
-	int i;
-	for (i = 0; i < sizeof (comb_table) / sizeof (*comb_table); i++) {
-		if (ch1 == comb_table[i].first &&
-		    ch2 == comb_table[i].last)
-			return (1);
-	}
-	return (0);
-}
diff --git a/usr.bin/less/cmdbuf.c b/usr.bin/less/cmdbuf.c
index aaafed8de75..0aaa1f0686d 100644
--- a/usr.bin/less/cmdbuf.c
+++ b/usr.bin/less/cmdbuf.c
@@ -179,19 +179,10 @@ cmd_step_common(char *p, LWCHAR ch, int len, int *pwidth, int *bswidth)
 				if (bswidth != NULL)
 					*bswidth = prlen;
 			} else {
-				LWCHAR prev_ch = step_char(&p, -1, cmdbuf);
-				if (is_combining_char(prev_ch, ch)) {
-					if (pwidth != NULL)
-						*pwidth = 0;
-					if (bswidth != NULL)
-						*bswidth = 0;
-				} else {
-					if (pwidth != NULL)
-						*pwidth	= is_wide_char(ch)
-						    ? 2 : 1;
-					if (bswidth != NULL)
-						*bswidth = 1;
-				}
+				if (pwidth != NULL)
+					*pwidth	= is_wide_char(ch) ? 2 : 1;
+				if (bswidth != NULL)
+					*bswidth = 1;
 			}
 		}
 	}
diff --git a/usr.bin/less/funcs.h b/usr.bin/less/funcs.h
index 5ef595a3bbe..2e707c3f606 100644
--- a/usr.bin/less/funcs.h
+++ b/usr.bin/less/funcs.h
@@ -65,7 +65,6 @@ LWCHAR step_char(char **, int, char *);
 int is_composing_char(LWCHAR);
 int is_ubin_char(LWCHAR);
 int is_wide_char(LWCHAR);
-int is_combining_char(LWCHAR, LWCHAR);
 void cmd_reset(void);
 void clear_cmd(void);
 void cmd_putstr(char *);
diff --git a/usr.bin/less/less.1 b/usr.bin/less/less.1
index 20acf5fe2d9..5a52be5da07 100644
--- a/usr.bin/less/less.1
+++ b/usr.bin/less/less.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: less.1,v 1.56 2019/08/20 11:34:18 jmc Exp $
+.\"	$OpenBSD: less.1,v 1.57 2019/09/02 14:07:45 schwarze Exp $
 .\"
 .\" Copyright (C) 1984-2012  Mark Nudelman
 .\"
@@ -23,7 +23,7 @@
 .\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: August 20 2019 $
+.Dd $Mdocdate: September 2 2019 $
 .Dt LESS 1
 .Os
 .Sh NAME
@@ -1804,7 +1804,7 @@ Language for determining the character set.
 The character encoding
 .Xr locale 1 .
 It decides which byte sequences form characters, what their display
-width is, and which characters are composing or combining characters.
+width is, and which characters are composing characters.
 .It Ev LESS
 Options which are passed to
 .Nm