Simplify usage of print_otag() even more:

accept NULL to skip the attribute or format.

3 files changed, 88 insertions, 86 deletions

diff --git a/html.c b/html.c
index 7af682e7..c3ab3b47 100644
--- a/html.c
+++ b/html.c
@@ -1,4 +1,4 @@
-/*	$Id: html.c,v 1.202 2017/01/26 18:28:18 schwarze Exp $ */
+/*	$Id: html.c,v 1.203 2017/01/28 22:36:38 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2011-2015, 2017 Ingo Schwarze <schwarze@openbsd.org>
@@ -449,7 +449,7 @@ print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 	char		 numbuf[16];
 	struct tag	*t;
 	const char	*attr;
-	char		*s;
+	char		*arg1, *arg2;
 	double		 v;
 	int		 i, have_style, tflags;
 
@@ -494,12 +494,14 @@ print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 	have_style = 0;
 	while (*fmt != '\0') {
 		if (*fmt == 's') {
-			print_word(h, " style=\"");
 			have_style = 1;
 			fmt++;
 			break;
 		}
-		s = va_arg(ap, char *);
+
+		/* Parse a non-style attribute and its arguments. */
+
+		arg1 = va_arg(ap, char *);
 		switch (*fmt++) {
 		case 'c':
 			attr = "class";
@@ -511,23 +513,31 @@ print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 			attr = "id";
 			break;
 		case '?':
-			attr = s;
-			s = va_arg(ap, char *);
+			attr = arg1;
+			arg1 = va_arg(ap, char *);
 			break;
 		default:
 			abort();
 		}
+		arg2 = NULL;
+		if (*fmt == 'M')
+			arg2 = va_arg(ap, char *);
+		if (arg1 == NULL)
+			continue;
+
+		/* Print the non-style attributes. */
+
 		print_byte(h, ' ');
 		print_word(h, attr);
 		print_byte(h, '=');
 		print_byte(h, '"');
 		switch (*fmt) {
 		case 'M':
-			print_href(h, s, va_arg(ap, char *), 1);
+			print_href(h, arg1, arg2, 1);
 			fmt++;
 			break;
 		case 'I':
-			print_href(h, s, NULL, 0);
+			print_href(h, arg1, NULL, 0);
 			fmt++;
 			break;
 		case 'R':
@@ -535,7 +545,7 @@ print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 			fmt++;
 			/* FALLTHROUGH */
 		default:
-			print_encode(h, s, NULL, 1);
+			print_encode(h, arg1, NULL, 1);
 			break;
 		}
 		print_byte(h, '"');
@@ -543,31 +553,35 @@ print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 
 	/* Print out styles. */
 
-	s = NULL;
-	su = &mysu;
 	while (*fmt != '\0') {
+		arg1 = NULL;
+		su = NULL;
 
 		/* First letter: input argument type. */
 
 		switch (*fmt++) {
 		case 'h':
 			i = va_arg(ap, int);
+			su = &mysu;
 			SCALE_HS_INIT(su, i);
 			break;
 		case 's':
-			s = va_arg(ap, char *);
+			arg1 = va_arg(ap, char *);
 			break;
 		case 'u':
 			su = va_arg(ap, struct roffsu *);
 			break;
 		case 'v':
 			i = va_arg(ap, int);
+			su = &mysu;
 			SCALE_VS_INIT(su, i);
 			break;
 		case 'w':
 		case 'W':
-			s = va_arg(ap, char *);
-			a2width(s, su);
+			if ((arg2 = va_arg(ap, char *)) == NULL)
+				break;
+			su = &mysu;
+			a2width(arg2, su);
 			if (fmt[-1] == 'W')
 				su->scale *= -1.0;
 			break;
@@ -600,33 +614,37 @@ print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 			attr = "min-width";
 			break;
 		case '?':
-			print_word(h, s);
-			print_byte(h, ':');
-			print_byte(h, ' ');
-			print_word(h, va_arg(ap, char *));
-			print_byte(h, ';');
-			if (*fmt != '\0')
-				print_byte(h, ' ');
-			continue;
+			attr = arg1;
+			arg1 = va_arg(ap, char *);
+			break;
 		default:
 			abort();
 		}
-		v = su->scale;
-		if (su->unit == SCALE_MM && (v /= 100.0) == 0.0)
-			v = 1.0;
-		else if (su->unit == SCALE_BU)
-			v /= 24.0;
+		if (su == NULL && arg1 == NULL)
+			continue;
+
+		if (have_style == 1)
+			print_word(h, " style=\"");
+		else
+			print_byte(h, ' ');
 		print_word(h, attr);
 		print_byte(h, ':');
 		print_byte(h, ' ');
-		(void)snprintf(numbuf, sizeof(numbuf), "%.2f", v);
-		print_word(h, numbuf);
-		print_word(h, roffscales[su->unit]);
+		if (su != NULL) {
+			v = su->scale;
+			if (su->unit == SCALE_MM && (v /= 100.0) == 0.0)
+				v = 1.0;
+			else if (su->unit == SCALE_BU)
+				v /= 24.0;
+			(void)snprintf(numbuf, sizeof(numbuf), "%.2f", v);
+			print_word(h, numbuf);
+			print_word(h, roffscales[su->unit]);
+		} else
+			print_word(h, arg1);
 		print_byte(h, ';');
-		if (*fmt != '\0')
-			print_byte(h, ' ');
+		have_style = 2;
 	}
-	if (have_style)
+	if (have_style == 2)
 		print_byte(h, '"');
 
 	va_end(ap);
diff --git a/mandoc_html.3 b/mandoc_html.3
index a77cdf45..3b48eb00 100644
--- a/mandoc_html.3
+++ b/mandoc_html.3
@@ -1,4 +1,4 @@
-.\"	$Id: mandoc_html.3,v 1.4 2017/01/25 02:14:43 schwarze Exp $
+.\"	$Id: mandoc_html.3,v 1.5 2017/01/28 22:36:38 schwarze Exp $
 .\"
 .\" Copyright (c) 2014, 2017 Ingo Schwarze <schwarze@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: January 25 2017 $
+.Dd $Mdocdate: January 28 2017 $
 .Dt MANDOC_HTML 3
 .Os
 .Sh NAME
@@ -137,6 +137,9 @@ Most attributes require one
 .Va char *
 argument which becomes the value of the attribute.
 The arguments have to be given in the same order as the attribute letters.
+If an argument is
+.Dv NULL ,
+the respective attribute is not written.
 .Bl -tag -width 1n -offset indent
 .It Cm c
 Print a
@@ -175,13 +178,15 @@ Print an arbitrary attribute.
 This format letter requires two
 .Vt char *
 arguments, the attribute name and the value.
+The name must not be
+.Dv NULL .
 .It Cm s
 Print a
 .Cm style
 attribute.
 If present, it must be the last format letter.
 In contrast to the other format letters, this one does not yet
-print the value and does not require an argument.
+print the value and does not take an argument.
 Instead, the rest of the format string consists of pairs of
 argument type letters and style name letters.
 .El
@@ -212,6 +217,9 @@ Requires one
 argument, interpreted as an
 .Xr mdoc 7 Ns -style
 width specifier.
+If the argument is
+.Dv NULL ,
+nothing is printed for this pair.
 .It Cm W
 Similar to
 .Cm w ,
@@ -255,6 +263,8 @@ requires two
 .Vt char *
 arguments.
 The first is the style name, the second its value.
+The style name must not be
+.Dv NULL .
 .El
 .Pp
 .Fn print_otag
@@ -340,5 +350,6 @@ implementation of common mandoc utility functions
 .An -nosplit
 The mandoc HTML formatter was written by
 .An Kristaps Dzonsons Aq Mt kristaps@bsd.lv .
-This manual was written by
-.An Ingo Schwarze Aq Mt schwarze@openbsd.org .
+It is maintained by
+.An Ingo Schwarze Aq Mt schwarze@openbsd.org ,
+who also wrote this manual.
diff --git a/mdoc_html.c b/mdoc_html.c
index 8bb15a25..eb35507e 100644
--- a/mdoc_html.c
+++ b/mdoc_html.c
@@ -1,4 +1,4 @@
-/*	$Id: mdoc_html.c,v 1.262 2017/01/28 18:43:00 schwarze Exp $ */
+/*	$Id: mdoc_html.c,v 1.263 2017/01/28 22:36:38 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2014, 2015, 2016, 2017 Ingo Schwarze <schwarze@openbsd.org>
@@ -507,22 +507,18 @@ mdoc_sh_pre(MDOC_ARGS)
 	char	*id;
 
 	switch (n->type) {
-	case ROFFT_BLOCK:
-		return 1;
+	case ROFFT_HEAD:
+		id = make_id(n);
+		print_otag(h, TAG_H1, "ci", "Sh", id);
+		free(id);
+		break;
 	case ROFFT_BODY:
 		if (n->sec == SEC_AUTHORS)
 			h->flags &= ~(HTML_SPLIT|HTML_NOSPLIT);
-		return 1;
+		break;
 	default:
 		break;
 	}
-
-	if ((id = make_id(n)) != NULL) {
-		print_otag(h, TAG_H1, "ci", "Sh", id);
-		free(id);
-	} else
-		print_otag(h, TAG_H1, "c", "Sh");
-
 	return 1;
 }
 
@@ -534,12 +530,9 @@ mdoc_ss_pre(MDOC_ARGS)
 	if (n->type != ROFFT_HEAD)
 		return 1;
 
-	if ((id = make_id(n)) != NULL) {
-		print_otag(h, TAG_H2, "ci", "Ss", id);
-		free(id);
-	} else
-		print_otag(h, TAG_H2, "c", "Ss");
-
+	id = make_id(n);
+	print_otag(h, TAG_H2, "ci", "Ss", id);
+	free(id);
 	return 1;
 }
 
@@ -749,11 +742,8 @@ mdoc_it_pre(MDOC_ARGS)
 				print_otag(h, TAG_B, "c", cattr);
 			break;
 		case ROFFT_BODY:
-			if (bl->norm->Bl.width == NULL)
-				print_otag(h, TAG_DD, "c", cattr);
-			else
-				print_otag(h, TAG_DD, "cswl", cattr,
-				    bl->norm->Bl.width);
+			print_otag(h, TAG_DD, "cswl", cattr,
+			    bl->norm->Bl.width);
 			break;
 		default:
 			break;
@@ -765,22 +755,16 @@ mdoc_it_pre(MDOC_ARGS)
 			if (h->style != NULL && !bl->norm->Bl.comp &&
 			    (n->parent->prev == NULL ||
 			     n->parent->prev->body->child != NULL)) {
-				if (bl->norm->Bl.width == NULL)
-					t = print_otag(h, TAG_DT, "c", cattr);
-				else
-					t = print_otag(h, TAG_DT, "csWl",
-					    cattr, bl->norm->Bl.width);
+				t = print_otag(h, TAG_DT, "csWl",
+				    cattr, bl->norm->Bl.width);
 				print_text(h, "\\ ");
 				print_tagq(h, t);
 				t = print_otag(h, TAG_DD, "c", cattr);
 				print_text(h, "\\ ");
 				print_tagq(h, t);
 			}
-			if (bl->norm->Bl.width == NULL)
-				print_otag(h, TAG_DT, "c", cattr);
-			else
-				print_otag(h, TAG_DT, "csWl", cattr,
-				    bl->norm->Bl.width);
+			print_otag(h, TAG_DT, "csWl", cattr,
+			    bl->norm->Bl.width);
 			break;
 		case ROFFT_BODY:
 			if (n->child == NULL) {
@@ -885,10 +869,7 @@ mdoc_bl_pre(MDOC_ARGS)
 		cattr = "Bl-tag";
 		if (bl->offs)
 			print_otag(h, TAG_DIV, "cswl", cattr, bl->offs);
-		if (bl->width == NULL)
-			print_otag(h, TAG_DL, "c", cattr);
-		else
-			print_otag(h, TAG_DL, "cswl", cattr, bl->width);
+		print_otag(h, TAG_DL, "cswl", cattr, bl->width);
 		return 1;
 	case LIST_column:
 		elemtype = TAG_TABLE;
@@ -897,12 +878,7 @@ mdoc_bl_pre(MDOC_ARGS)
 	default:
 		abort();
 	}
-
-	if (bl->offs)
-		print_otag(h, elemtype, "cswl", cattr, bl->offs);
-	else
-		print_otag(h, elemtype, "c", cattr);
-
+	print_otag(h, elemtype, "cswl", cattr, bl->offs);
 	return 1;
 }
 
@@ -940,12 +916,9 @@ mdoc_sx_pre(MDOC_ARGS)
 {
 	char	*id;
 
-	if ((id = make_id(n)) != NULL) {
-		print_otag(h, TAG_A, "chR", "Sx", id);
-		free(id);
-	} else
-		print_otag(h, TAG_A, "c", "Sx");
-
+	id = make_id(n);
+	print_otag(h, TAG_A, "chR", "Sx", id);
+	free(id);
 	return 1;
 }