Support nesting of indented blocks.

This patch was originally written in July 2011 by kristaps@,
i promptly committed it to OpenBSD, and then it was forgotten.
Now i rediscovered it when merging 1.11.7 to OpenBSD.

ok kristaps@  (on his own patch :)

1 files changed, 28 insertions, 34 deletions

diff --git a/man_term.c b/man_term.c
index 8399381b..398271f9 100644
--- a/man_term.c
+++ b/man_term.c
@@ -33,29 +33,19 @@
 #include "term.h"
 #include "main.h"
 
-#define	INDENT		  7
-#define	HALFINDENT	  3
+#define	INDENT		  7 /* fixed-width char full-indent */
+#define	HALFINDENT	  3 /* fixed-width char half-indent */
+#define	MAXMARGINS	  64 /* maximum number of indented scopes */
 
 /* FIXME: have PD set the default vspace width. */
 
 struct	mtermp {
 	int		  fl;
 #define	MANT_LITERAL	 (1 << 0)
-	/* 
-	 * Default amount to indent the left margin after leading text
-	 * has been printed (e.g., `HP' left-indent, `TP' and `IP' body
-	 * indent).  This needs to be saved because `HP' and so on, if
-	 * not having a specified value, must default.
-	 *
-	 * Note that this is the indentation AFTER the left offset, so
-	 * the total offset is usually offset + lmargin.
-	 */
-	size_t		  lmargin;
-	/*
-	 * The default offset, i.e., the amount between any text and the
-	 * page boundary.
-	 */
-	size_t		  offset;
+	size_t		  lmargin[MAXMARGINS]; /* margins (incl. visible page) */
+	int		  lmargincur; /* index of current margin */
+	int		  lmarginsz; /* actual number of nested margins */
+	size_t		  offset; /* default offset to visible page */
 };
 
 #define	DECL_ARGS 	  struct termp *p, \
@@ -164,8 +154,9 @@ terminal_man(void *arg, const struct man *man)
 	term_begin(p, print_man_head, print_man_foot, m);
 	p->flags |= TERMP_NOSPACE;
 
-	mt.fl = 0;
-	mt.lmargin = term_len(p, INDENT);
+	memset(&mt, 0, sizeof(struct mtermp));
+
+	mt.lmargin[mt.lmargincur] = term_len(p, INDENT);
 	mt.offset = term_len(p, INDENT);
 
 	if (n->child)
@@ -456,7 +447,7 @@ pre_HP(DECL_ARGS)
 		return(0);
 	}
 
-	len = mt->lmargin;
+	len = mt->lmargin[mt->lmargincur];
 	ival = -1;
 
 	/* Calculate offset. */
@@ -472,7 +463,7 @@ pre_HP(DECL_ARGS)
 	p->rmargin = mt->offset + len;
 
 	if (ival >= 0)
-		mt->lmargin = (size_t)ival;
+		mt->lmargin[mt->lmargincur] = (size_t)ival;
 
 	return(1);
 }
@@ -507,7 +498,7 @@ pre_PP(DECL_ARGS)
 
 	switch (n->type) {
 	case (MAN_BLOCK):
-		mt->lmargin = term_len(p, INDENT);
+		mt->lmargin[mt->lmargincur] = term_len(p, INDENT);
 		print_bvspace(p, n);
 		break;
 	default:
@@ -542,7 +533,7 @@ pre_IP(DECL_ARGS)
 		return(1);
 	}
 
-	len = mt->lmargin;
+	len = mt->lmargin[mt->lmargincur];
 	ival = -1;
 
 	/* Calculate the offset from the optional second argument. */
@@ -563,7 +554,7 @@ pre_IP(DECL_ARGS)
 			break;
 
 		/* Set the saved left-margin. */
-		mt->lmargin = (size_t)ival;
+		mt->lmargin[mt->lmargincur] = (size_t)ival;
 
 		savelit = MANT_LITERAL & mt->fl;
 		mt->fl &= ~MANT_LITERAL;
@@ -631,18 +622,15 @@ pre_TP(DECL_ARGS)
 		return(1);
 	}
 
-	len = (size_t)mt->lmargin;
+	len = (size_t)mt->lmargin[mt->lmargincur];
 	ival = -1;
 
 	/* Calculate offset. */
 
-	if (NULL != (nn = n->parent->head->child)) {
-		while (nn && MAN_TEXT != nn->type)
-			nn = nn->next;
-		if (nn && nn->next)
+	if (NULL != (nn = n->parent->head->child))
+		if (nn->parent->line == nn->line)
 			if ((ival = a2width(p, nn->string)) >= 0)
 				len = (size_t)ival;
-	}
 
 	switch (n->type) {
 	case (MAN_HEAD):
@@ -663,9 +651,8 @@ pre_TP(DECL_ARGS)
 
 		if (savelit)
 			mt->fl |= MANT_LITERAL;
-
 		if (ival >= 0)
-			mt->lmargin = (size_t)ival;
+			mt->lmargin[mt->lmargincur] = (size_t)ival;
 
 		return(0);
 	case (MAN_BODY):
@@ -710,7 +697,7 @@ pre_SS(DECL_ARGS)
 	switch (n->type) {
 	case (MAN_BLOCK):
 		mt->fl &= ~MANT_LITERAL;
-		mt->lmargin = term_len(p, INDENT);
+		mt->lmargin[mt->lmargincur] = term_len(p, INDENT);
 		mt->offset = term_len(p, INDENT);
 		/* If following a prior empty `SS', no vspace. */
 		if (n->prev && MAN_SS == n->prev->tok)
@@ -761,7 +748,7 @@ pre_SH(DECL_ARGS)
 	switch (n->type) {
 	case (MAN_BLOCK):
 		mt->fl &= ~MANT_LITERAL;
-		mt->lmargin = term_len(p, INDENT);
+		mt->lmargin[mt->lmargincur] = term_len(p, INDENT);
 		mt->offset = term_len(p, INDENT);
 		/* If following a prior empty `SH', no vspace. */
 		if (n->prev && MAN_SH == n->prev->tok)
@@ -830,6 +817,10 @@ pre_RS(DECL_ARGS)
 	mt->offset += sz;
 	p->offset = mt->offset;
 
+	if (++mt->lmarginsz < MAXMARGINS)
+		mt->lmargincur = mt->lmarginsz;
+
+	mt->lmargin[mt->lmargincur] = mt->lmargin[mt->lmargincur - 1];
 	return(1);
 }
 
@@ -858,6 +849,9 @@ post_RS(DECL_ARGS)
 
 	mt->offset = mt->offset < sz ?  0 : mt->offset - sz;
 	p->offset = mt->offset;
+
+	if (--mt->lmarginsz < MAXMARGINS)
+		mt->lmargincur = mt->lmarginsz;
 }
 
 static void