Do not break output lines in .Fn function arguments in SYNOPSIS mode.

Following an idea from Franco Fichtner, but implemented more cleanly.
This reduces groff-mandoc-differences in base by a fantastic 7.5%.

7 files changed, 57 insertions, 8 deletions

diff --git a/regress/usr.bin/mandoc/mdoc/Fo/Makefile b/regress/usr.bin/mandoc/mdoc/Fo/Makefile
index 48facb8351c..88adf0c6490 100644
--- a/regress/usr.bin/mandoc/mdoc/Fo/Makefile
+++ b/regress/usr.bin/mandoc/mdoc/Fo/Makefile
@@ -1,8 +1,8 @@
-# $OpenBSD: Makefile,v 1.6 2012/11/18 00:05:28 schwarze Exp $
+# $OpenBSD: Makefile,v 1.7 2013/12/25 00:39:14 schwarze Exp $
 
-REGRESS_TARGETS = basic section noarg font eos
+REGRESS_TARGETS = basic section break noarg font eos
 
-# groff 1.21 does not handle .nr nS
+# groff does not handle .nr nS
 
 SKIP_GROFF ?= section
 
diff --git a/regress/usr.bin/mandoc/mdoc/Fo/break.in b/regress/usr.bin/mandoc/mdoc/Fo/break.in
new file mode 100644
index 00000000000..2a5d1dcd699
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Fo/break.in
@@ -0,0 +1,11 @@
+.Dd December 25, 2013
+.Dt FO-BREAK 1
+.Os OpenBSD
+.Sh NAME
+.Nm Fo-break
+.Nd line breaks in function blocks
+.Sh SYNOPSIS
+.Ft my_long_return_type *
+.Fn my_long_function "my_long_type first_argument" "my_long_type second_argument"
+.Sh DESCRIPTION
+.Fn my_long_function "my_long_type first_argument" "my_long_type second_argument"
diff --git a/regress/usr.bin/mandoc/mdoc/Fo/break.out_ascii b/regress/usr.bin/mandoc/mdoc/Fo/break.out_ascii
new file mode 100644
index 00000000000..a3379b74989
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Fo/break.out_ascii
@@ -0,0 +1,15 @@
+FO-BREAK(1)                OpenBSD Reference Manual                FO-BREAK(1)
+
+NNAAMMEE
+     FFoo--bbrreeaakk - line breaks in function blocks
+
+SSYYNNOOPPSSIISS
+     _m_y___l_o_n_g___r_e_t_u_r_n___t_y_p_e _*
+     mmyy__lloonngg__ffuunnccttiioonn(_m_y___l_o_n_g___t_y_p_e _f_i_r_s_t___a_r_g_u_m_e_n_t,
+         _m_y___l_o_n_g___t_y_p_e _s_e_c_o_n_d___a_r_g_u_m_e_n_t);
+
+DDEESSCCRRIIPPTTIIOONN
+     mmyy__lloonngg__ffuunnccttiioonn(_m_y___l_o_n_g___t_y_p_e _f_i_r_s_t___a_r_g_u_m_e_n_t, _m_y___l_o_n_g___t_y_p_e
+     _s_e_c_o_n_d___a_r_g_u_m_e_n_t)
+
+OpenBSD                        December 25, 2013                       OpenBSD
diff --git a/usr.bin/mandoc/mdoc_man.c b/usr.bin/mandoc/mdoc_man.c
index 2cc23418785..5b713b3a596 100644
--- a/usr.bin/mandoc/mdoc_man.c
+++ b/usr.bin/mandoc/mdoc_man.c
@@ -1,4 +1,4 @@
-/*	$Id: mdoc_man.c,v 1.54 2013/12/24 22:08:23 schwarze Exp $ */
+/*	$Id: mdoc_man.c,v 1.55 2013/12/25 00:39:13 schwarze Exp $ */
 /*
  * Copyright (c) 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
  *
@@ -252,6 +252,7 @@ static	int		outflags;
 #define	MMAN_An_split	(1 << 9)  /* author mode is "split" */
 #define	MMAN_An_nosplit	(1 << 10) /* author mode is "nosplit" */
 #define	MMAN_PD		(1 << 11) /* inter-paragraph spacing disabled */
+#define	MMAN_nbrword	(1 << 12) /* do not break the next word */
 
 #define	BL_STACK_MAX	32
 
@@ -360,6 +361,12 @@ print_word(const char *s)
 		case (ASCII_HYPH):
 			putchar('-');
 			break;
+		case (' '):
+			if (MMAN_nbrword & outflags) {
+				printf("\\ ");
+				break;
+			}
+			/* FALLTHROUGH */
 		default:
 			putchar((unsigned char)*s);
 			break;
@@ -367,6 +374,7 @@ print_word(const char *s)
 		if (TPremain)
 			TPremain--;
 	}
+	outflags &= ~MMAN_nbrword;
 }
 
 static void
@@ -1024,6 +1032,8 @@ pre_fa(DECL_ARGS)
 
 	while (NULL != n) {
 		font_push('I');
+		if (MDOC_SYNPRETTY & n->flags)
+			outflags |= MMAN_nbrword;
 		print_node(meta, n);
 		font_pop();
 		if (NULL != (n = n->next))
diff --git a/usr.bin/mandoc/mdoc_term.c b/usr.bin/mandoc/mdoc_term.c
index 162a832a916..ac5b7e0d0c7 100644
--- a/usr.bin/mandoc/mdoc_term.c
+++ b/usr.bin/mandoc/mdoc_term.c
@@ -1,4 +1,4 @@
-/*	$Id: mdoc_term.c,v 1.156 2013/12/24 23:04:29 schwarze Exp $ */
+/*	$Id: mdoc_term.c,v 1.157 2013/12/25 00:39:13 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
@@ -1560,6 +1560,8 @@ termp_fn_pre(DECL_ARGS)
 	for (n = n->next; n; n = n->next) {
 		assert(MDOC_TEXT == n->type);
 		term_fontpush(p, TERMFONT_UNDER);
+		if (pretty)
+			p->flags |= TERMP_NBRWORD;
 		term_word(p, n->string);
 		term_fontpop(p);
 
diff --git a/usr.bin/mandoc/term.c b/usr.bin/mandoc/term.c
index 0a6a2232877..795a3fdb167 100644
--- a/usr.bin/mandoc/term.c
+++ b/usr.bin/mandoc/term.c
@@ -1,4 +1,4 @@
-/*	$Id: term.c,v 1.74 2013/12/24 23:04:29 schwarze Exp $ */
+/*	$Id: term.c,v 1.75 2013/12/25 00:39:13 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
@@ -403,6 +403,7 @@ term_fontpop(struct termp *p)
 void
 term_word(struct termp *p, const char *word)
 {
+	const char	 nbrsp[2] = { ASCII_NBRSP, 0 };
 	const char	*seq, *cp;
 	char		 c;
 	int		 sz, uc;
@@ -434,7 +435,15 @@ term_word(struct termp *p, const char *word)
 				word++;
 				continue;
 			}
-			ssz = strcspn(word, "\\");
+			if (TERMP_NBRWORD & p->flags) {
+				if (' ' == *word) {
+					encode(p, nbrsp, 1);
+					word++;
+					continue;
+				}
+				ssz = strcspn(word, "\\ ");
+			} else
+				ssz = strcspn(word, "\\");
 			encode(p, word, ssz);
 			word += (int)ssz;
 			continue;
@@ -509,6 +518,7 @@ term_word(struct termp *p, const char *word)
 			break;
 		}
 	}
+	p->flags &= ~TERMP_NBRWORD;
 }
 
 static void
diff --git a/usr.bin/mandoc/term.h b/usr.bin/mandoc/term.h
index d890c4b7703..4da26f96ac5 100644
--- a/usr.bin/mandoc/term.h
+++ b/usr.bin/mandoc/term.h
@@ -1,4 +1,4 @@
-/*	$Id: term.h,v 1.40 2013/12/24 23:04:29 schwarze Exp $ */
+/*	$Id: term.h,v 1.41 2013/12/25 00:39:13 schwarze Exp $ */
 /*
  * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2011, 2012, 2013 Ingo Schwarze <schwarze@openbsd.org>
@@ -71,6 +71,7 @@ struct	termp {
 #define	TERMP_SENTENCE	 (1 << 1)	/* Space before a sentence. */
 #define	TERMP_NOSPACE	 (1 << 2)	/* No space before words. */
 #define	TERMP_NONOSPACE	 (1 << 3)	/* No space (no autounset). */
+#define	TERMP_NBRWORD	 (1 << 4)	/* Make next word nonbreaking. */
 #define	TERMP_KEEP	 (1 << 5)	/* Keep words together. */
 #define	TERMP_PREKEEP	 (1 << 6)	/* ...starting with the next one. */
 #define	TERMP_SKIPCHAR	 (1 << 7)	/* Skip the next character. */