Finally delete the kitchensink functions rew_sub() and rew_dohalt().

They were a maintenance and auditing nightmare because if you changed
one bit in there, stuff tended to break at seemingly unrelated places.
No functional change except getting rid of one bogus error message,
but minus 80 lines of code.

2 files changed, 75 insertions, 161 deletions

diff --git a/regress/usr.bin/mandoc/mdoc/Bl/break.out_lint b/regress/usr.bin/mandoc/mdoc/Bl/break.out_lint
index c534bee29c1..cb20bc25513 100644
--- a/regress/usr.bin/mandoc/mdoc/Bl/break.out_lint
+++ b/regress/usr.bin/mandoc/mdoc/Bl/break.out_lint
@@ -6,7 +6,6 @@ mandoc: break.in:41:2: WARNING: blocks badly nested: Bl breaks Bd
 mandoc: break.in:42:2: ERROR: skipping item outside list: It 
 mandoc: break.in:49:2: WARNING: blocks badly nested: Bl breaks Bo
 mandoc: break.in:51:2: ERROR: inserting missing end of block: Sh breaks Bo
-mandoc: break.in:51:2: ERROR: inserting missing end of block: Sh breaks It
 mandoc: break.in:54:2: WARNING: blocks badly nested: Bl breaks Bo
 mandoc: break.in:53:25: ERROR: appending missing end of block: Bo
 mandoc: break.in:52:2: ERROR: appending missing end of block: Bl
diff --git a/usr.bin/mandoc/mdoc_macro.c b/usr.bin/mandoc/mdoc_macro.c
index 12e7dd62dcb..21885b10a8e 100644
--- a/usr.bin/mandoc/mdoc_macro.c
+++ b/usr.bin/mandoc/mdoc_macro.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mdoc_macro.c,v 1.126 2015/02/03 00:48:27 schwarze Exp $ */
+/*	$OpenBSD: mdoc_macro.c,v 1.127 2015/02/03 01:13:48 schwarze Exp $ */
 /*
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010, 2012-2015 Ingo Schwarze <schwarze@openbsd.org>
@@ -29,13 +29,6 @@
 #include "libmdoc.h"
 #include "libmandoc.h"
 
-enum	rew {	/* see rew_dohalt() */
-	REWIND_NONE,
-	REWIND_THIS,
-	REWIND_MORE,
-	REWIND_FORCE
-};
-
 static	void		blk_full(MACRO_PROT_ARGS);
 static	void		blk_exp_close(MACRO_PROT_ARGS);
 static	void		blk_part_exp(MACRO_PROT_ARGS);
@@ -57,13 +50,9 @@ static	void		make_pending(struct mdoc *, struct mdoc_node *,
 static	int		parse_rest(struct mdoc *, enum mdoct,
 				int, int *, char *);
 static	enum mdoct	rew_alt(enum mdoct);
-static	enum rew	rew_dohalt(enum mdoct, enum mdoc_type,
-				const struct mdoc_node *);
 static	void		rew_elem(struct mdoc *, enum mdoct);
 static	void		rew_last(struct mdoc *, const struct mdoc_node *);
 static	void		rew_pending(struct mdoc *, const struct mdoc_node *);
-static	void		rew_sub(enum mdoc_type, struct mdoc *,
-				enum mdoct, int, int);
 
 const	struct mdoc_macro __mdoc_macros[MDOC_MAX] = {
 	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Ap */
@@ -355,95 +344,6 @@ rew_alt(enum mdoct tok)
 	/* NOTREACHED */
 }
 
-/*
- * Rewinding to tok, how do we have to handle *p?
- * REWIND_NONE: *p would delimit tok, but no tok scope is open
- *   inside *p, so there is no need to rewind anything at all.
- * REWIND_THIS: *p matches tok, so rewind *p and nothing else.
- * REWIND_MORE: *p is implicit, rewind it and keep searching for tok.
- * REWIND_FORCE: *p is explicit, but tok is full, force rewinding *p.
- */
-static enum rew
-rew_dohalt(enum mdoct tok, enum mdoc_type type,
-		const struct mdoc_node *p)
-{
-
-	/*
-	 * No matching token, no delimiting block, no broken block.
-	 * This can happen when full implicit macros are called for
-	 * the first time but try to rewind their previous
-	 * instance anyway.
-	 */
-	if (MDOC_ROOT == p->type)
-		return(REWIND_NONE);
-
-	/*
-	 * When starting to rewind, skip plain text
-	 * and nodes that have already been rewound.
-	 */
-	if (p->type == MDOC_TEXT || p->flags & (MDOC_VALID | MDOC_BREAK))
-		return(REWIND_MORE);
-
-	/*
-	 * The easiest case:  Found a matching token.
-	 * This applies to both blocks and elements.
-	 */
-	tok = rew_alt(tok);
-	if (tok == p->tok)
-		return(type == p->type ? REWIND_THIS : REWIND_MORE);
-
-	/*
-	 * While elements do require rewinding for themselves,
-	 * they never affect rewinding of other nodes.
-	 */
-	if (MDOC_ELEM == p->type)
-		return(REWIND_MORE);
-
-	/*
-	 * Blocks delimited by our target token get REWIND_MORE.
-	 * Blocks delimiting our target token get REWIND_NONE.
-	 */
-	switch (tok) {
-	case MDOC_It:
-		if (MDOC_BODY == p->type && MDOC_Bl == p->tok)
-			return(REWIND_NONE);
-		break;
-	case MDOC_Nm:
-		return(REWIND_NONE);
-	case MDOC_Nd:
-		/* FALLTHROUGH */
-	case MDOC_Ss:
-		if (MDOC_BODY == p->type && MDOC_Sh == p->tok)
-			return(REWIND_NONE);
-		/* FALLTHROUGH */
-	case MDOC_Sh:
-		if (MDOC_ROOT == p->parent->type)
-			return(REWIND_THIS);
-		if (MDOC_Nd == p->tok || MDOC_Ss == p->tok ||
-		    MDOC_Sh == p->tok)
-			return(REWIND_MORE);
-		break;
-	default:
-		break;
-	}
-
-	/*
-	 * Default block rewinding rules.
-	 * In particular, let all blocks rewind Nm children.
-	 * Do not warn again when closing a block,
-	 * since closing the body already warned.
-	 */
-	if (MDOC_Nm == p->tok ||
-	    MDOC_BLOCK == type || MDOC_BLOCK == p->type)
-		return(REWIND_MORE);
-
-	/*
-	 * By default, closing out full blocks
-	 * forces closing of broken explicit blocks.
-	 */
-	return (REWIND_FORCE);
-}
-
 static void
 rew_elem(struct mdoc *mdoc, enum mdoct tok)
 {
@@ -529,45 +429,6 @@ make_pending(struct mdoc *mdoc, struct mdoc_node *breaker,
 		breaker->body->flags |= MDOC_BREAK;
 }
 
-static void
-rew_sub(enum mdoc_type t, struct mdoc *mdoc,
-		enum mdoct tok, int line, int ppos)
-{
-	struct mdoc_node *n, *to;
-
-	to = NULL;
-	n = mdoc->last;
-	while (n) {
-		switch (rew_dohalt(tok, t, n)) {
-		case REWIND_NONE:
-			if (to == NULL)
-				return;
-			n = to;
-			break;
-		case REWIND_THIS:
-			n->lastline = line -
-			    (mdoc->flags & MDOC_NEWLINE &&
-			     ! (mdoc_macros[tok].flags & MDOC_EXPLICIT));
-			break;
-		case REWIND_FORCE:
-			mandoc_vmsg(MANDOCERR_BLK_BROKEN, mdoc->parse,
-			    line, ppos, "%s breaks %s",
-			    mdoc_macronames[tok],
-			    mdoc_macronames[n->tok]);
-			/* FALLTHROUGH */
-		case REWIND_MORE:
-			n->lastline = line -
-			    (mdoc->flags & MDOC_NEWLINE ? 1 : 0);
-			to = n;
-			n = n->parent;
-			continue;
-		}
-		break;
-	}
-	assert(n);
-	rew_pending(mdoc, n);
-}
-
 /*
  * Allocate a word and check whether it's punctuation or not.
  * Punctuation consists of those tokens found in mdoc_isdelim().
@@ -678,10 +539,11 @@ blk_exp_close(MACRO_PROT_ARGS)
 {
 	struct mdoc_node *body;		/* Our own body. */
 	struct mdoc_node *endbody;	/* Our own end marker. */
+	struct mdoc_node *itblk;	/* An It block starting later. */
 	struct mdoc_node *later;	/* A sub-block starting later. */
 	struct mdoc_node *n;		/* Search back to our block. */
 
-	int		 have_it, j, lastarg, maxargs, nl;
+	int		 j, lastarg, maxargs, nl;
 	enum margserr	 ac;
 	enum mdoct	 atok, ntok;
 	char		*p;
@@ -705,9 +567,8 @@ blk_exp_close(MACRO_PROT_ARGS)
 	 * both of our own and of pending sub-blocks.
 	 */
 
-	have_it = 0;
 	atok = rew_alt(tok);
-	body = endbody = later = NULL;
+	body = endbody = itblk = later = NULL;
 	for (n = mdoc->last; n; n = n->parent) {
 		if (n->flags & (MDOC_VALID | MDOC_BREAK))
 			continue;
@@ -726,7 +587,7 @@ blk_exp_close(MACRO_PROT_ARGS)
 			continue;
 
 		if (n->tok == MDOC_It) {
-			have_it = 1;
+			itblk = n;
 			continue;
 		}
 
@@ -741,7 +602,7 @@ blk_exp_close(MACRO_PROT_ARGS)
 			 */
 
 			if (later == NULL ||
-			    (tok == MDOC_El && !have_it))
+			    (tok == MDOC_El && itblk == NULL))
 				break;
 
 			/*
@@ -751,6 +612,8 @@ blk_exp_close(MACRO_PROT_ARGS)
 			 */
 
 			make_pending(mdoc, n, later, line, ppos);
+			if (tok == MDOC_El)
+				itblk->flags |= MDOC_BREAK;
 
 			/*
 			 * Mark the place where the formatting - but not
@@ -805,7 +668,7 @@ blk_exp_close(MACRO_PROT_ARGS)
 			    mdoc->parse, line, ppos,
 			    "%s %s", mdoc_macronames[tok],
 			    buf + *pos);
-		if (endbody == NULL)
+		if (endbody == NULL && n != NULL)
 			rew_pending(mdoc, n);
 		return;
 	}
@@ -1036,7 +899,7 @@ blk_full(MACRO_PROT_ARGS)
 {
 	int		  la, nl, parsed;
 	struct mdoc_arg	 *arg;
-	struct mdoc_node *blk; /* Our own block. */
+	struct mdoc_node *blk; /* Our own or a broken block. */
 	struct mdoc_node *head; /* Our own head. */
 	struct mdoc_node *body; /* Our own body. */
 	struct mdoc_node *n;
@@ -1045,14 +908,73 @@ blk_full(MACRO_PROT_ARGS)
 
 	nl = MDOC_NEWLINE & mdoc->flags;
 
-	/* Skip items outside lists. */
+	if ( ! (mdoc_macros[tok].flags & MDOC_EXPLICIT)) {
 
-	if (tok == MDOC_It) {
-		for (n = mdoc->last; n; n = n->parent)
-			if (n->tok == MDOC_Bl && n->type == MDOC_BLOCK &&
-			    ! (n->flags & (MDOC_VALID | MDOC_BREAK)))
+		/* Here, tok is one of Sh Ss Nm Nd It. */
+
+		blk = NULL;
+		for (n = mdoc->last; n != NULL; n = n->parent) {
+			if (n->flags & (MDOC_VALID | MDOC_BREAK) ||
+			    n->type != MDOC_BLOCK)
+				continue;
+			if (tok == MDOC_It && n->tok == MDOC_Bl) {
+				if (blk != NULL) {
+					mandoc_vmsg(MANDOCERR_BLK_BROKEN,
+					    mdoc->parse, line, ppos,
+					    "It breaks %s",
+					    mdoc_macronames[blk->tok]);
+					rew_pending(mdoc, blk);
+				}
 				break;
-		if (n == NULL) {
+			}
+
+			if (mdoc_macros[n->tok].flags & MDOC_EXPLICIT) {
+				switch (tok) {
+				case MDOC_Sh:
+					/* FALLTHROUGH */
+				case MDOC_Ss:
+					mandoc_vmsg(MANDOCERR_BLK_BROKEN,
+					    mdoc->parse, line, ppos,
+					    "%s breaks %s",
+					    mdoc_macronames[tok],
+					    mdoc_macronames[n->tok]);
+					rew_pending(mdoc, n);
+					continue;
+				case MDOC_It:
+					/* Delay in case it's astray. */
+					blk = n;
+					continue;
+				default:
+					break;
+				}
+				break;
+			}
+
+			/* Here, n is one of Sh Ss Nm Nd It. */
+
+			if (tok != MDOC_Sh && (n->tok == MDOC_Sh ||
+			    (tok != MDOC_Ss && (n->tok == MDOC_Ss ||
+			     (tok != MDOC_It && n->tok == MDOC_It)))))
+				break;
+
+			/* Item breaking an explicit block. */
+
+			if (blk != NULL) {
+				mandoc_vmsg(MANDOCERR_BLK_BROKEN,
+				    mdoc->parse, line, ppos,
+				    "It breaks %s",
+				    mdoc_macronames[blk->tok]);
+				rew_pending(mdoc, blk);
+			}
+
+			/* Close out prior implicit scopes. */
+
+			rew_last(mdoc, n);
+		}
+
+		/* Skip items outside lists. */
+
+		if (tok == MDOC_It && (n == NULL || n->tok != MDOC_Bl)) {
 			mandoc_vmsg(MANDOCERR_IT_STRAY, mdoc->parse,
 			    line, ppos, "It %s", buf + *pos);
 			mdoc_elem_alloc(mdoc, line, ppos, MDOC_br, NULL);
@@ -1061,13 +983,6 @@ blk_full(MACRO_PROT_ARGS)
 		}
 	}
 
-	/* Close out prior implicit scope. */
-
-	if ( ! (mdoc_macros[tok].flags & MDOC_EXPLICIT)) {
-		rew_sub(MDOC_BODY, mdoc, tok, line, ppos);
-		rew_sub(MDOC_BLOCK, mdoc, tok, line, ppos);
-	}
-
 	/*
 	 * This routine accommodates implicitly- and explicitly-scoped
 	 * macro openings.  Implicit ones first close out prior scope