Delete complicated code dealing with .Bl -tag without -width,

and just let it default to -width 6n, which agrees with the
traditional -width Ds that is still in widespread use.

I just pushed a patch upstream to GNU roff that does the same for
groff_mdoc(7).  Before, groff contained code that was even more
complicated than mandoc, but both resulted in quite different
user-visible output.  Now, both agree, and output is nicer for both.

Useless complication noticed by Carsten Kunze (Heirloom roff).

4 files changed, 7 insertions, 88 deletions

diff --git a/usr.bin/mandoc/mandoc.h b/usr.bin/mandoc/mandoc.h
index 7a733fa3d62..c10730d026b 100644
--- a/usr.bin/mandoc/mandoc.h
+++ b/usr.bin/mandoc/mandoc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mandoc.h,v 1.151 2016/01/08 02:53:09 schwarze Exp $ */
+/*	$OpenBSD: mandoc.h,v 1.152 2016/10/09 18:16:46 schwarze Exp $ */
 /*
  * Copyright (c) 2010, 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2016 Ingo Schwarze <schwarze@openbsd.org>
@@ -98,7 +98,7 @@ enum	mandocerr {
 	MANDOCERR_ARG_EMPTY, /* empty argument, using 0n: macro arg */
 	MANDOCERR_BD_NOTYPE, /* missing display type, using -ragged: Bd */
 	MANDOCERR_BL_LATETYPE, /* list type is not the first argument: Bl arg */
-	MANDOCERR_BL_NOWIDTH, /* missing -width in -tag list, using 8n */
+	MANDOCERR_BL_NOWIDTH, /* missing -width in -tag list, using 6n */
 	MANDOCERR_EX_NONAME, /* missing utility name, using "": Ex */
 	MANDOCERR_FO_NOHEAD, /* missing function name, using "": Fo */
 	MANDOCERR_IT_NOHEAD, /* empty head in list item: Bl -type It */
diff --git a/usr.bin/mandoc/mdoc_term.c b/usr.bin/mandoc/mdoc_term.c
index 93d3dbc3361..17c4d9513a1 100644
--- a/usr.bin/mandoc/mdoc_term.c
+++ b/usr.bin/mandoc/mdoc_term.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mdoc_term.c,v 1.230 2016/01/08 17:48:04 schwarze Exp $ */
+/*	$OpenBSD: mdoc_term.c,v 1.231 2016/10/09 18:16:46 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2012-2016 Ingo Schwarze <schwarze@openbsd.org>
@@ -629,10 +629,10 @@ termp_it_pre(DECL_ARGS)
 		width = term_len(p, 2);
 		break;
 	case LIST_hang:
+	case LIST_tag:
 		width = term_len(p, 8);
 		break;
 	case LIST_column:
-	case LIST_tag:
 		width = term_len(p, 10);
 		break;
 	default:
diff --git a/usr.bin/mandoc/mdoc_validate.c b/usr.bin/mandoc/mdoc_validate.c
index d1d9bb4d7e2..a087a21a470 100644
--- a/usr.bin/mandoc/mdoc_validate.c
+++ b/usr.bin/mandoc/mdoc_validate.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mdoc_validate.c,v 1.224 2016/08/20 14:43:39 schwarze Exp $ */
+/*	$OpenBSD: mdoc_validate.c,v 1.225 2016/10/09 18:16:46 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2016 Ingo Schwarze <schwarze@openbsd.org>
@@ -65,7 +65,6 @@ static	void	 post_bf(POST_ARGS);
 static	void	 post_bk(POST_ARGS);
 static	void	 post_bl(POST_ARGS);
 static	void	 post_bl_block(POST_ARGS);
-static	void	 post_bl_block_tag(POST_ARGS);
 static	void	 post_bl_head(POST_ARGS);
 static	void	 post_bl_norm(POST_ARGS);
 static	void	 post_bx(POST_ARGS);
@@ -1090,22 +1089,7 @@ post_bl_block(POST_ARGS)
 
 	post_prevpar(mdoc);
 
-	/*
-	 * These are fairly complicated, so we've broken them into two
-	 * functions.  post_bl_block_tag() is called when a -tag is
-	 * specified, but no -width (it must be guessed).  The second
-	 * when a -width is specified (macro indicators must be
-	 * rewritten into real lengths).
-	 */
-
 	n = mdoc->last;
-
-	if (n->norm->Bl.type == LIST_tag &&
-	    n->norm->Bl.width == NULL) {
-		post_bl_block_tag(mdoc);
-		assert(n->norm->Bl.width != NULL);
-	}
-
 	for (ni = n->body->child; ni != NULL; ni = ni->next) {
 		if (ni->body == NULL)
 			continue;
@@ -1163,71 +1147,6 @@ rewrite_macro2len(char **arg)
 }
 
 static void
-post_bl_block_tag(POST_ARGS)
-{
-	struct roff_node *n, *nn;
-	size_t		  sz, ssz;
-	int		  i;
-	char		  buf[24];
-
-	/*
-	 * Calculate the -width for a `Bl -tag' list if it hasn't been
-	 * provided.  Uses the first head macro.  NOTE AGAIN: this is
-	 * ONLY if the -width argument has NOT been provided.  See
-	 * rewrite_macro2len() for converting the -width string.
-	 */
-
-	sz = 10;
-	n = mdoc->last;
-
-	for (nn = n->body->child; nn != NULL; nn = nn->next) {
-		if (nn->tok != MDOC_It)
-			continue;
-
-		assert(nn->type == ROFFT_BLOCK);
-		nn = nn->head->child;
-
-		if (nn == NULL)
-			break;
-
-		if (nn->type == ROFFT_TEXT) {
-			sz = strlen(nn->string) + 1;
-			break;
-		}
-
-		if (0 != (ssz = macro2len(nn->tok)))
-			sz = ssz;
-
-		break;
-	}
-
-	/* Defaults to ten ens. */
-
-	(void)snprintf(buf, sizeof(buf), "%un", (unsigned int)sz);
-
-	/*
-	 * We have to dynamically add this to the macro's argument list.
-	 * We're guaranteed that a MDOC_Width doesn't already exist.
-	 */
-
-	assert(n->args != NULL);
-	i = (int)(n->args->argc)++;
-
-	n->args->argv = mandoc_reallocarray(n->args->argv,
-	    n->args->argc, sizeof(struct mdoc_argv));
-
-	n->args->argv[i].arg = MDOC_Width;
-	n->args->argv[i].line = n->line;
-	n->args->argv[i].pos = n->pos;
-	n->args->argv[i].sz = 1;
-	n->args->argv[i].value = mandoc_malloc(sizeof(char *));
-	n->args->argv[i].value[0] = mandoc_strdup(buf);
-
-	/* Set our width! */
-	n->norm->Bl.width = n->args->argv[i].value[0];
-}
-
-static void
 post_bl_head(POST_ARGS)
 {
 	struct roff_node *nbl, *nh, *nch, *nnext;
diff --git a/usr.bin/mandoc/read.c b/usr.bin/mandoc/read.c
index 65ecff72194..63d7b20a9ad 100644
--- a/usr.bin/mandoc/read.c
+++ b/usr.bin/mandoc/read.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: read.c,v 1.124 2016/07/19 16:22:34 schwarze Exp $ */
+/*	$OpenBSD: read.c,v 1.125 2016/10/09 18:16:46 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010-2016 Ingo Schwarze <schwarze@openbsd.org>
@@ -136,7 +136,7 @@ static	const char * const	mandocerrs[MANDOCERR_MAX] = {
 	"empty argument, using 0n",
 	"missing display type, using -ragged",
 	"list type is not the first argument",
-	"missing -width in -tag list, using 8n",
+	"missing -width in -tag list, using 6n",
 	"missing utility name, using \"\"",
 	"missing function name, using \"\"",
 	"empty head in list item",