Normalise SYNOPSIS behaviour after I gave up on following groff's

inconsistent behaviour.  In short:

       Some macros are displayed differently in the SYNOPSIS
       section, particularly Nm, Cd, Fd, Fn, Fo, In, Vt, and Ft.
       All of these macros are output on their own line.  If two
       such dissimilar macros are pair-wise invoked (except for Ft
       before Fo or Fn), they are separated by a vertical space,
       unless in the case of Fo, Fn, and Ft, which are always
       separated by vertical space.

Behaviour ok Jason McIntyre, ingo@.  Fallout will be treated
case-by-case.

I had to clear out some regressions that were testing against groff's
stranger behaviours: these will now break, as we don't care about such
invocations.

Also removed the newline for `Cd' invocation in a non-SYNOPSIS context.

1 files changed, 90 insertions, 76 deletions

diff --git a/mdoc_term.c b/mdoc_term.c
index e62d7219..84583caf 100644
--- a/mdoc_term.c
+++ b/mdoc_term.c
@@ -68,6 +68,8 @@ static	void  	  print_mdoc_node(DECL_ARGS);
 static	void	  print_mdoc_head(DECL_ARGS);
 static	void	  print_mdoc_nodelist(DECL_ARGS);
 static	void	  print_foot(DECL_ARGS);
+static	void	  synopsis_pre(struct termp *, 
+			const struct mdoc_node *);
 
 static	void	  termp____post(DECL_ARGS);
 static	void	  termp_an_post(DECL_ARGS);
@@ -79,8 +81,7 @@ static	void	  termp_brq_post(DECL_ARGS);
 static	void	  termp_bx_post(DECL_ARGS);
 static	void	  termp_d1_post(DECL_ARGS);
 static	void	  termp_dq_post(DECL_ARGS);
-static	void	  termp_fd_post(DECL_ARGS);
-static	void	  termp_fn_post(DECL_ARGS);
+static	int	  termp_fd_pre(DECL_ARGS);
 static	void	  termp_fo_post(DECL_ARGS);
 static	void	  termp_in_post(DECL_ARGS);
 static	void	  termp_it_post(DECL_ARGS);
@@ -92,7 +93,6 @@ static	void	  termp_qq_post(DECL_ARGS);
 static	void	  termp_sh_post(DECL_ARGS);
 static	void	  termp_sq_post(DECL_ARGS);
 static	void	  termp_ss_post(DECL_ARGS);
-static	void	  termp_vt_post(DECL_ARGS);
 
 static	int	  termp_an_pre(DECL_ARGS);
 static	int	  termp_ap_pre(DECL_ARGS);
@@ -162,9 +162,9 @@ static	const struct termact termacts[MDOC_MAX] = {
 	{ NULL, NULL }, /* Ev */ 
 	{ termp_ex_pre, NULL }, /* Ex */
 	{ termp_fa_pre, NULL }, /* Fa */ 
-	{ termp_bold_pre, termp_fd_post }, /* Fd */ 
+	{ termp_fd_pre, NULL }, /* Fd */ 
 	{ termp_fl_pre, NULL }, /* Fl */
-	{ termp_fn_pre, termp_fn_post }, /* Fn */ 
+	{ termp_fn_pre, NULL }, /* Fn */ 
 	{ termp_ft_pre, NULL }, /* Ft */ 
 	{ termp_bold_pre, NULL }, /* Ic */ 
 	{ termp_in_pre, termp_in_post }, /* In */ 
@@ -177,7 +177,7 @@ static	const struct termact termacts[MDOC_MAX] = {
 	{ termp_rv_pre, NULL }, /* Rv */
 	{ NULL, NULL }, /* St */ 
 	{ termp_under_pre, NULL }, /* Va */
-	{ termp_vt_pre, termp_vt_post }, /* Vt */
+	{ termp_vt_pre, NULL }, /* Vt */
 	{ termp_xr_pre, NULL }, /* Xr */
 	{ NULL, termp____post }, /* %A */
 	{ termp_under_pre, termp____post }, /* %B */
@@ -1055,14 +1055,11 @@ termp_nm_pre(DECL_ARGS)
 	if (NULL == n->child && NULL == m->name)
 		return(1);
 
-	if (SEC_SYNOPSIS == n->sec && MDOC_LINE & n->flags)
-		term_newln(p);
+	synopsis_pre(p, n);
 
 	term_fontpush(p, TERMFONT_BOLD);
-
 	if (NULL == n->child)
 		term_word(p, m->name);
-
 	return(1);
 }
 
@@ -1313,32 +1310,78 @@ termp_xr_pre(DECL_ARGS)
 }
 
 
-static int
-termp_vt_pre(DECL_ARGS)
+/*
+ * This decides how to assert whitespace before any of the SYNOPSIS set
+ * of macros (which, as in the case of Ft/Fo and Ft/Fn, may contain
+ * macro combos).
+ */
+static void
+synopsis_pre(struct termp *p, const struct mdoc_node *n)
 {
+	/* 
+	 * Obviously, if we're not in a SYNOPSIS or no prior macros
+	 * exist, do nothing.
+	 */
+	if (NULL == n->prev || SEC_SYNOPSIS != n->sec)
+		return;
 
-	if (MDOC_ELEM == n->type)
-		return(termp_under_pre(p, pair, m, n));
-	else if (MDOC_HEAD == n->type)
-		return(0);
-	else if (MDOC_BLOCK == n->type)
-		return(1);
+	/*
+	 * If we're the second in a pair of like elements, emit our
+	 * newline and return.  UNLESS we're `Fo', `Fn', `Fn', in which
+	 * case we soldier on.
+	 */
+	if (n->prev->tok == n->tok && 
+			MDOC_Ft != n->tok && 
+			MDOC_Fo != n->tok && 
+			MDOC_Fn != n->tok) {
+		term_newln(p);
+		return;
+	}
 
-	return(termp_under_pre(p, pair, m, n));
+	/*
+	 * If we're one of the SYNOPSIS set and non-like pair-wise after
+	 * another (or Fn/Fo, which we've let slip through) then assert
+	 * vertical space, else only newline and move on.
+	 */
+	switch (n->prev->tok) {
+	case (MDOC_Fd):
+		/* FALLTHROUGH */
+	case (MDOC_Fn):
+		/* FALLTHROUGH */
+	case (MDOC_Fo):
+		/* FALLTHROUGH */
+	case (MDOC_In):
+		/* FALLTHROUGH */
+	case (MDOC_Vt):
+		term_vspace(p);
+		break;
+	case (MDOC_Ft):
+		if (MDOC_Fn != n->tok && MDOC_Fo != n->tok) {
+			term_vspace(p);
+			break;
+		}
+		/* FALLTHROUGH */
+	default:
+		term_newln(p);
+		break;
+	}
 }
 
 
-/* ARGSUSED */
-static void
-termp_vt_post(DECL_ARGS)
+static int
+termp_vt_pre(DECL_ARGS)
 {
 
-	if (MDOC_BLOCK != n->type)
-		return;
-	if (n->next && MDOC_Vt == n->next->tok)
-		term_newln(p);
-	else if (n->next)
-		term_vspace(p);
+	if (MDOC_ELEM == n->type) {
+		synopsis_pre(p, n);
+		return(termp_under_pre(p, pair, m, n));
+	} else if (MDOC_BLOCK == n->type) {
+		synopsis_pre(p, n);
+		return(1);
+	} else if (MDOC_HEAD == n->type)
+		return(0);
+
+	return(termp_under_pre(p, pair, m, n));
 }
 
 
@@ -1353,11 +1396,12 @@ termp_bold_pre(DECL_ARGS)
 
 
 /* ARGSUSED */
-static void
-termp_fd_post(DECL_ARGS)
+static int
+termp_fd_pre(DECL_ARGS)
 {
 
-	term_newln(p);
+	synopsis_pre(p, n);
+	return(termp_bold_pre(p, pair, m, n));
 }
 
 
@@ -1511,9 +1555,7 @@ termp_ft_pre(DECL_ARGS)
 {
 
 	/* NB: MDOC_LINE does not effect this! */
-	if (SEC_SYNOPSIS == n->sec && n->prev)
-		term_vspace(p);
-
+	synopsis_pre(p, n);
 	term_fontpush(p, TERMFONT_UNDER);
 	return(1);
 }
@@ -1525,13 +1567,7 @@ termp_fn_pre(DECL_ARGS)
 {
 	const struct mdoc_node	*nn;
 
-	/* NB: MDOC_LINE has no effect on this macro! */
-	if (SEC_SYNOPSIS == n->sec) {
-		if (n->prev && MDOC_Ft == n->prev->tok)
-			term_newln(p);
-		else if (n->prev)
-			term_vspace(p);
-	}
+	synopsis_pre(p, n);
 
 	term_fontpush(p, TERMFONT_BOLD);
 	term_word(p, n->child->string);
@@ -1559,17 +1595,6 @@ termp_fn_pre(DECL_ARGS)
 
 
 /* ARGSUSED */
-static void
-termp_fn_post(DECL_ARGS)
-{
-
-	/* NB: MDOC_LINE has no effect on this macro! */
-	if (SEC_SYNOPSIS == n->sec)
-		term_newln(p);
-}
-
-
-/* ARGSUSED */
 static int
 termp_fa_pre(DECL_ARGS)
 {
@@ -1834,8 +1859,8 @@ static int
 termp_cd_pre(DECL_ARGS)
 {
 
+	synopsis_pre(p, n);
 	term_fontpush(p, TERMFONT_BOLD);
-	term_newln(p);
 	return(1);
 }
 
@@ -1845,8 +1870,7 @@ static int
 termp_in_pre(DECL_ARGS)
 {
 
-	if (SEC_SYNOPSIS == n->sec && n->prev && MDOC_In != n->prev->tok)
-		term_vspace(p);
+	synopsis_pre(p, n);
 
 	if (SEC_SYNOPSIS == n->sec && MDOC_LINE & n->flags) {
 		term_fontpush(p, TERMFONT_BOLD);
@@ -1867,16 +1891,14 @@ static void
 termp_in_post(DECL_ARGS)
 {
 
-	if (SEC_SYNOPSIS == n->sec && MDOC_LINE & n->flags)
+	if (SEC_SYNOPSIS == n->sec)
 		term_fontpush(p, TERMFONT_BOLD);
 
 	p->flags |= TERMP_NOSPACE;
 	term_word(p, ">");
 
-	if (SEC_SYNOPSIS == n->sec && MDOC_LINE & n->flags) {
+	if (SEC_SYNOPSIS == n->sec)
 		term_fontpop(p);
-		term_newln(p);
-	}
 }
 
 
@@ -1987,13 +2009,7 @@ termp_fo_pre(DECL_ARGS)
 {
 
 	if (MDOC_BLOCK == n->type) {
-		/* NB: MDOC_LINE has no effect on this macro! */
-		if (SEC_SYNOPSIS != n->sec)
-			return(1);
-		if (n->prev && MDOC_Ft == n->prev->tok)
-			term_newln(p);
-		else if (n->prev)
-			term_vspace(p);
+		synopsis_pre(p, n);
 		return(1);
 	} else if (MDOC_BODY == n->type) {
 		p->flags |= TERMP_NOSPACE;
@@ -2017,17 +2033,15 @@ static void
 termp_fo_post(DECL_ARGS)
 {
 
-	if (MDOC_BLOCK == n->type) {
-		/* NB: MDOC_LINE has no effect on this macro! */
-		if (SEC_SYNOPSIS == n->sec)
-			term_newln(p);
-	} else if (MDOC_BODY == n->type) {
+	if (MDOC_BODY != n->type) 
+		return;
+
+	p->flags |= TERMP_NOSPACE;
+	term_word(p, ")");
+
+	if (SEC_SYNOPSIS == n->sec) {
 		p->flags |= TERMP_NOSPACE;
-		term_word(p, ")");
-		if (SEC_SYNOPSIS == n->sec) {
-			p->flags |= TERMP_NOSPACE;
-			term_word(p, ";");
-		}
+		term_word(p, ";");
 	}
 }