[BACK]Return to mdoc_macro.c CVS log [TXT][DIR] Up to [cvsweb.bsd.lv] / mandoc

File: [cvsweb.bsd.lv] / mandoc / mdoc_macro.c (download)

Revision 1.158, Thu Dec 18 03:10:11 2014 UTC (9 years, 3 months ago) by schwarze
Branch: MAIN
Changes since 1.157: +32 -21 lines

The code is already careful to not add items to lists that were
already closed.  In this respect, also consider lists closed
that have broken another block, their closure pending until the
end of the broken block.  This avoids syntax tree corruption
leading to a NULL pointer access found by jsg@ with afl.

/*	$Id: mdoc_macro.c,v 1.158 2014/12/18 03:10:11 schwarze Exp $ */
/*
 * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2010, 2012, 2013, 2014 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "config.h"

#include <sys/types.h>

#include <assert.h>
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#include "mdoc.h"
#include "mandoc.h"
#include "libmdoc.h"
#include "libmandoc.h"

enum	rew {	/* see rew_dohalt() */
	REWIND_NONE,
	REWIND_THIS,
	REWIND_MORE,
	REWIND_FORCE,
	REWIND_LATER,
	REWIND_ERROR
};

static	void		blk_full(MACRO_PROT_ARGS);
static	void		blk_exp_close(MACRO_PROT_ARGS);
static	void		blk_part_exp(MACRO_PROT_ARGS);
static	void		blk_part_imp(MACRO_PROT_ARGS);
static	void		ctx_synopsis(MACRO_PROT_ARGS);
static	void		in_line_eoln(MACRO_PROT_ARGS);
static	void		in_line_argn(MACRO_PROT_ARGS);
static	void		in_line(MACRO_PROT_ARGS);
static	void		phrase_ta(MACRO_PROT_ARGS);

static	void		dword(struct mdoc *, int, int, const char *,
				 enum mdelim, int);
static	void		append_delims(struct mdoc *, int, int *, char *);
static	enum mdoct	lookup(struct mdoc *, enum mdoct,
				int, int, const char *);
static	int		macro_or_word(MACRO_PROT_ARGS, int);
static	int		make_pending(struct mdoc_node *, enum mdoct,
				struct mdoc *, int, int);
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_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 */
	{ in_line_eoln, MDOC_PROLOGUE }, /* Dd */
	{ in_line_eoln, MDOC_PROLOGUE }, /* Dt */
	{ in_line_eoln, MDOC_PROLOGUE }, /* Os */
	{ blk_full, MDOC_PARSED | MDOC_JOIN }, /* Sh */
	{ blk_full, MDOC_PARSED | MDOC_JOIN }, /* Ss */
	{ in_line_eoln, 0 }, /* Pp */
	{ blk_part_imp, MDOC_PARSED | MDOC_JOIN }, /* D1 */
	{ blk_part_imp, MDOC_PARSED | MDOC_JOIN }, /* Dl */
	{ blk_full, MDOC_EXPLICIT }, /* Bd */
	{ blk_exp_close, MDOC_EXPLICIT | MDOC_JOIN }, /* Ed */
	{ blk_full, MDOC_EXPLICIT }, /* Bl */
	{ blk_exp_close, MDOC_EXPLICIT | MDOC_JOIN }, /* El */
	{ blk_full, MDOC_PARSED | MDOC_JOIN }, /* It */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Ad */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* An */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Ar */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Cd */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Cm */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Dv */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Er */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Ev */
	{ in_line_eoln, 0 }, /* Ex */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Fa */
	{ in_line_eoln, 0 }, /* Fd */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Fl */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Fn */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Ft */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Ic */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* In */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Li */
	{ blk_full, MDOC_JOIN }, /* Nd */
	{ ctx_synopsis, MDOC_CALLABLE | MDOC_PARSED }, /* Nm */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED }, /* Op */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Ot */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Pa */
	{ in_line_eoln, 0 }, /* Rv */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* St */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Va */
	{ ctx_synopsis, MDOC_CALLABLE | MDOC_PARSED }, /* Vt */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Xr */
	{ in_line_eoln, MDOC_JOIN }, /* %A */
	{ in_line_eoln, MDOC_JOIN }, /* %B */
	{ in_line_eoln, MDOC_JOIN }, /* %D */
	{ in_line_eoln, MDOC_JOIN }, /* %I */
	{ in_line_eoln, MDOC_JOIN }, /* %J */
	{ in_line_eoln, 0 }, /* %N */
	{ in_line_eoln, MDOC_JOIN }, /* %O */
	{ in_line_eoln, 0 }, /* %P */
	{ in_line_eoln, MDOC_JOIN }, /* %R */
	{ in_line_eoln, MDOC_JOIN }, /* %T */
	{ in_line_eoln, 0 }, /* %V */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Ac */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* Ao */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Aq */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* At */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Bc */
	{ blk_full, MDOC_EXPLICIT }, /* Bf */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* Bo */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Bq */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Bsx */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Bx */
	{ in_line_eoln, 0 }, /* Db */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Dc */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* Do */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Dq */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED | MDOC_EXPLICIT }, /* Ec */
	{ blk_exp_close, MDOC_EXPLICIT | MDOC_JOIN }, /* Ef */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Em */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED | MDOC_EXPLICIT }, /* Eo */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Fx */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Ms */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* No */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_IGNDELIM | MDOC_JOIN }, /* Ns */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Nx */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Ox */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Pc */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED | MDOC_IGNDELIM }, /* Pf */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* Po */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Pq */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Qc */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Ql */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* Qo */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Qq */
	{ blk_exp_close, MDOC_EXPLICIT | MDOC_JOIN }, /* Re */
	{ blk_full, MDOC_EXPLICIT }, /* Rs */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Sc */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* So */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Sq */
	{ in_line_argn, 0 }, /* Sm */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Sx */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Sy */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Tn */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Ux */
	{ blk_exp_close, MDOC_EXPLICIT | MDOC_CALLABLE | MDOC_PARSED }, /* Xc */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED | MDOC_EXPLICIT }, /* Xo */
	{ blk_full, MDOC_EXPLICIT | MDOC_CALLABLE }, /* Fo */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Fc */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* Oo */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Oc */
	{ blk_full, MDOC_EXPLICIT }, /* Bk */
	{ blk_exp_close, MDOC_EXPLICIT | MDOC_JOIN }, /* Ek */
	{ in_line_eoln, 0 }, /* Bt */
	{ in_line_eoln, 0 }, /* Hf */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Fr */
	{ in_line_eoln, 0 }, /* Ud */
	{ in_line, 0 }, /* Lb */
	{ in_line_eoln, 0 }, /* Lp */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Lk */
	{ in_line, MDOC_CALLABLE | MDOC_PARSED }, /* Mt */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Brq */
	{ blk_part_exp, MDOC_CALLABLE | MDOC_PARSED |
			MDOC_EXPLICIT | MDOC_JOIN }, /* Bro */
	{ blk_exp_close, MDOC_CALLABLE | MDOC_PARSED |
			 MDOC_EXPLICIT | MDOC_JOIN }, /* Brc */
	{ in_line_eoln, MDOC_JOIN }, /* %C */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Es */
	{ blk_part_imp, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* En */
	{ in_line_argn, MDOC_CALLABLE | MDOC_PARSED }, /* Dx */
	{ in_line_eoln, MDOC_JOIN }, /* %Q */
	{ in_line_eoln, 0 }, /* br */
	{ in_line_eoln, 0 }, /* sp */
	{ in_line_eoln, 0 }, /* %U */
	{ phrase_ta, MDOC_CALLABLE | MDOC_PARSED | MDOC_JOIN }, /* Ta */
	{ in_line_eoln, MDOC_PROLOGUE }, /* ll */
};

const	struct mdoc_macro * const mdoc_macros = __mdoc_macros;


/*
 * This is called at the end of parsing.  It must traverse up the tree,
 * closing out open [implicit] scopes.  Obviously, open explicit scopes
 * are errors.
 */
void
mdoc_macroend(struct mdoc *mdoc)
{
	struct mdoc_node *n;

	/* Scan for open explicit scopes. */

	n = mdoc->last->flags & MDOC_VALID ?
	    mdoc->last->parent : mdoc->last;

	for ( ; n; n = n->parent)
		if (n->type == MDOC_BLOCK &&
		    mdoc_macros[n->tok].flags & MDOC_EXPLICIT)
			mandoc_msg(MANDOCERR_BLK_NOEND, mdoc->parse,
			    n->line, n->pos, mdoc_macronames[n->tok]);

	/* Rewind to the first. */

	rew_last(mdoc, mdoc->first);
}

/*
 * Look up the macro at *p called by "from",
 * or as a line macro if from == MDOC_MAX.
 */
static enum mdoct
lookup(struct mdoc *mdoc, enum mdoct from, int line, int ppos, const char *p)
{
	enum mdoct	 res;

	if (from == MDOC_MAX || mdoc_macros[from].flags & MDOC_PARSED) {
		res = mdoc_hash_find(p);
		if (res != MDOC_MAX) {
			if (mdoc_macros[res].flags & MDOC_CALLABLE)
				return(res);
			if (res != MDOC_br && res != MDOC_sp && res != MDOC_ll)
				mandoc_msg(MANDOCERR_MACRO_CALL,
				    mdoc->parse, line, ppos, p);
		}
	}
	return(MDOC_MAX);
}

static void
rew_last(struct mdoc *mdoc, const struct mdoc_node *to)
{
	struct mdoc_node *n, *np;

	assert(to);
	mdoc->next = MDOC_NEXT_SIBLING;
	while (mdoc->last != to) {
		/*
		 * Save the parent here, because we may delete the
		 * mdoc->last node in the post-validation phase and reset
		 * it to mdoc->last->parent, causing a step in the closing
		 * out to be lost.
		 */
		np = mdoc->last->parent;
		mdoc_valid_post(mdoc);
		n = mdoc->last;
		mdoc->last = np;
		assert(mdoc->last);
		mdoc->last->last = n;
	}
	mdoc_valid_post(mdoc);
}

/*
 * For a block closing macro, return the corresponding opening one.
 * Otherwise, return the macro itself.
 */
static enum mdoct
rew_alt(enum mdoct tok)
{
	switch (tok) {
	case MDOC_Ac:
		return(MDOC_Ao);
	case MDOC_Bc:
		return(MDOC_Bo);
	case MDOC_Brc:
		return(MDOC_Bro);
	case MDOC_Dc:
		return(MDOC_Do);
	case MDOC_Ec:
		return(MDOC_Eo);
	case MDOC_Ed:
		return(MDOC_Bd);
	case MDOC_Ef:
		return(MDOC_Bf);
	case MDOC_Ek:
		return(MDOC_Bk);
	case MDOC_El:
		return(MDOC_Bl);
	case MDOC_Fc:
		return(MDOC_Fo);
	case MDOC_Oc:
		return(MDOC_Oo);
	case MDOC_Pc:
		return(MDOC_Po);
	case MDOC_Qc:
		return(MDOC_Qo);
	case MDOC_Re:
		return(MDOC_Rs);
	case MDOC_Sc:
		return(MDOC_So);
	case MDOC_Xc:
		return(MDOC_Xo);
	default:
		return(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.
 * REWIND_LATER: *p is explicit and still open, postpone rewinding.
 * REWIND_ERROR: No tok block is open at all.
 */
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(MDOC_BLOCK == type &&
		    MDOC_EXPLICIT & mdoc_macros[tok].flags ?
		    REWIND_ERROR : REWIND_NONE);

	/*
	 * When starting to rewind, skip plain text
	 * and nodes that have already been rewound.
	 */
	if (MDOC_TEXT == p->type || MDOC_VALID & p->flags)
		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(p->end ? REWIND_NONE :
		    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_Bl:
		if (MDOC_It == p->tok)
			return(REWIND_MORE);
		break;
	case MDOC_It:
		if (MDOC_BODY == p->type && MDOC_Bl == p->tok)
			return(REWIND_NONE);
		break;
	/*
	 * XXX Badly nested block handling still fails badly
	 * when one block is breaking two blocks of the same type.
	 * This is an incomplete and extremely ugly workaround,
	 * required to let the OpenBSD tree build.
	 */
	case MDOC_Oo:
		if (MDOC_Op == p->tok)
			return(REWIND_MORE);
		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, always skip block end markers,
	 * and let all blocks rewind Nm children.
	 * Do not warn again when closing a block,
	 * since closing the body already warned.
	 */
	if (ENDBODY_NOT != p->end || MDOC_Nm == p->tok ||
	    MDOC_BLOCK == type || (MDOC_BLOCK == p->type &&
	    ! (MDOC_EXPLICIT & mdoc_macros[tok].flags)))
		return(REWIND_MORE);

	/*
	 * By default, closing out full blocks
	 * forces closing of broken explicit blocks,
	 * while closing out partial blocks
	 * allows delayed rewinding by default.
	 */
	return (&blk_full == mdoc_macros[tok].fp ?
	    REWIND_FORCE : REWIND_LATER);
}

static void
rew_elem(struct mdoc *mdoc, enum mdoct tok)
{
	struct mdoc_node *n;

	n = mdoc->last;
	if (MDOC_ELEM != n->type)
		n = n->parent;
	assert(MDOC_ELEM == n->type);
	assert(tok == n->tok);
	rew_last(mdoc, n);
}

/*
 * We are trying to close a block identified by tok,
 * but the child block *broken is still open.
 * Thus, postpone closing the tok block
 * until the rew_sub call closing *broken.
 */
static int
make_pending(struct mdoc_node *broken, enum mdoct tok,
		struct mdoc *mdoc, int line, int ppos)
{
	struct mdoc_node *breaker;

	/*
	 * Iterate backwards, searching for the block matching tok,
	 * that is, the block breaking the *broken block.
	 */
	for (breaker = broken->parent; breaker; breaker = breaker->parent) {

		/*
		 * If the *broken block (Z) is already broken and we
		 * encounter its breaker (B), make the tok block (A)
		 * pending on that inner breaker (B).
		 * Graphically, [A breaker=[B! broken=[Z->B B] tok=A] Z]
		 * becomes breaker=[A broken=[B! [Z->B B] tok=A] Z]
		 * and finally [A! [B!->A [Z->B B] A] Z].
		 * In these graphics, "->" indicates the "pending"
		 * pointer and "!" indicates the MDOC_BREAK flag.
		 * Each of the cases gets one additional pointer (B->A)
		 * and one additional flag (A!).
		 */
		if (breaker == broken->pending) {
			broken = breaker;
			continue;
		}

		if (REWIND_THIS != rew_dohalt(tok, MDOC_BLOCK, breaker))
			continue;
		if (MDOC_BODY == broken->type)
			broken = broken->parent;

		/*
		 * Found the breaker.
		 * If another, outer breaker (X) is already pending on
		 * the *broken block (B), we must not clobber the link
		 * to the outer breaker, but make it pending on the
		 * new, now inner breaker (A).
		 * Graphically, [X! breaker=[A broken=[B->X X] tok=A] B]
		 * becomes [X! breaker=[A->X broken=[B X] tok=A] B]
		 * and finally [X! [A!->X [B->A X] A] B].
		 */
		if (broken->pending) {
			struct mdoc_node *taker;

			/*
			 * If the inner breaker (A) is already broken,
			 * too, it cannot take on the outer breaker (X)
			 * but must hand it on to its own breakers (Y):
			 * [X! [Y! breaker=[A->Y Y] broken=[B->X X] tok=A] B]
			 * [X! take=[Y!->X brea=[A->Y Y] brok=[B X] tok=A] B]
			 * and finally [X! [Y!->X [A!->Y Y] [B->A X] A] B].
			 */
			taker = breaker;
			while (taker->pending)
				taker = taker->pending;
			taker->pending = broken->pending;
		}

		/*
		 * Now we have reduced the situation to the simplest
		 * case, which is just breaker=[A broken=[B tok=A] B]
		 * and becomes [A! [B->A A] B].
		 */
		broken->pending = breaker;
		breaker->flags |= MDOC_BREAK;
		mandoc_vmsg(MANDOCERR_BLK_NEST, mdoc->parse, line, ppos,
		    "%s breaks %s", mdoc_macronames[tok],
		    mdoc_macronames[broken->tok]);
		return(1);
	}

	/*
	 * Found no matching block for tok.
	 * Are you trying to close a block that is not open?
	 */
	return(0);
}

static void
rew_sub(enum mdoc_type t, struct mdoc *mdoc,
		enum mdoct tok, int line, int ppos)
{
	struct mdoc_node *n;

	n = mdoc->last;
	while (n) {
		switch (rew_dohalt(tok, t, n)) {
		case REWIND_NONE:
			return;
		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);
			n = n->parent;
			continue;
		case REWIND_LATER:
			if (make_pending(n, tok, mdoc, line, ppos) ||
			    t != MDOC_BLOCK)
				return;
			/* FALLTHROUGH */
		case REWIND_ERROR:
			mandoc_msg(MANDOCERR_BLK_NOTOPEN,
			    mdoc->parse, line, ppos,
			    mdoc_macronames[tok]);
			return;
		}
		break;
	}
	assert(n);
	rew_last(mdoc, n);

	/*
	 * The current block extends an enclosing block.
	 * Now that the current block ends, close the enclosing block, too.
	 */
	while ((n = n->pending) != NULL) {
		rew_last(mdoc, n);
		if (n->type == MDOC_HEAD)
			mdoc_body_alloc(mdoc, n->line, n->pos, n->tok);
	}
}

/*
 * Allocate a word and check whether it's punctuation or not.
 * Punctuation consists of those tokens found in mdoc_isdelim().
 */
static void
dword(struct mdoc *mdoc, int line, int col, const char *p,
		enum mdelim d, int may_append)
{

	if (d == DELIM_MAX)
		d = mdoc_isdelim(p);

	if (may_append &&
	    ! (mdoc->flags & (MDOC_SYNOPSIS | MDOC_KEEP | MDOC_SMOFF)) &&
	    d == DELIM_NONE && mdoc->last->type == MDOC_TEXT &&
	    mdoc_isdelim(mdoc->last->string) == DELIM_NONE) {
		mdoc_word_append(mdoc, p);
		return;
	}

	mdoc_word_alloc(mdoc, line, col, p);

	/*
	 * If the word consists of a bare delimiter,
	 * flag the new node accordingly,
	 * unless doing so was vetoed by the invoking macro.
	 * Always clear the veto, it is only valid for one word.
	 */

	if (d == DELIM_OPEN)
		mdoc->last->flags |= MDOC_DELIMO;
	else if (d == DELIM_CLOSE &&
	    ! (mdoc->flags & MDOC_NODELIMC) &&
	    mdoc->last->parent->tok != MDOC_Fd)
		mdoc->last->flags |= MDOC_DELIMC;
	mdoc->flags &= ~MDOC_NODELIMC;
}

static void
append_delims(struct mdoc *mdoc, int line, int *pos, char *buf)
{
	char		*p;
	int		 la;

	if (buf[*pos] == '\0')
		return;

	for (;;) {
		la = *pos;
		if (mdoc_args(mdoc, line, pos, buf, MDOC_MAX, &p) == ARGS_EOLN)
			break;
		dword(mdoc, line, la, p, DELIM_MAX, 1);

		/*
		 * If we encounter end-of-sentence symbols, then trigger
		 * the double-space.
		 *
		 * XXX: it's easy to allow this to propagate outward to
		 * the last symbol, such that `. )' will cause the
		 * correct double-spacing.  However, (1) groff isn't
		 * smart enough to do this and (2) it would require
		 * knowing which symbols break this behaviour, for
		 * example, `.  ;' shouldn't propagate the double-space.
		 */

		if (mandoc_eos(p, strlen(p)))
			mdoc->last->flags |= MDOC_EOS;
	}
}

/*
 * Parse one word.
 * If it is a macro, call it and return 1.
 * Otherwise, allocate it and return 0.
 */
static int
macro_or_word(MACRO_PROT_ARGS, int parsed)
{
	char		*p;
	enum mdoct	 ntok;

	p = buf + ppos;
	ntok = MDOC_MAX;
	if (*p == '"')
		p++;
	else if (parsed && ! (mdoc->flags & MDOC_PHRASELIT))
		ntok = lookup(mdoc, tok, line, ppos, p);

	if (ntok == MDOC_MAX) {
		dword(mdoc, line, ppos, p, DELIM_MAX, tok == MDOC_MAX ||
		    mdoc_macros[tok].flags & MDOC_JOIN);
		return(0);
	} else {
		if (mdoc_macros[tok].fp == in_line_eoln)
			rew_elem(mdoc, tok);
		mdoc_macro(mdoc, ntok, line, ppos, pos, buf);
		if (tok == MDOC_MAX)
			append_delims(mdoc, line, pos, buf);
		return(1);
	}
}

/*
 * Close out block partial/full explicit.
 */
static void
blk_exp_close(MACRO_PROT_ARGS)
{
	struct mdoc_node *body;		/* Our own body. */
	struct mdoc_node *endbody;	/* Our own end marker. */
	struct mdoc_node *later;	/* A sub-block starting later. */
	struct mdoc_node *n;		/* For searching backwards. */

	int		 j, lastarg, maxargs, flushed, nl;
	enum margserr	 ac;
	enum mdoct	 atok, ntok;
	char		*p;

	nl = MDOC_NEWLINE & mdoc->flags;

	switch (tok) {
	case MDOC_Ec:
		maxargs = 1;
		break;
	case MDOC_Ek:
		mdoc->flags &= ~MDOC_KEEP;
		/* FALLTHROUGH */
	default:
		maxargs = 0;
		break;
	}

	/*
	 * Search backwards for beginnings of blocks,
	 * both of our own and of pending sub-blocks.
	 */

	atok = rew_alt(tok);
	body = endbody = later = NULL;
	for (n = mdoc->last; n; n = n->parent) {
		if (n->flags & MDOC_VALID)
			continue;

		/* Remember the start of our own body. */

		if (n->type == MDOC_BODY && atok == n->tok) {
			if (n->end == ENDBODY_NOT)
				body = n;
			continue;
		}

		if (n->type != MDOC_BLOCK || n->tok == MDOC_Nm)
			continue;
		if (atok == n->tok) {
			assert(body);

			/*
			 * Found the start of our own block.
			 * When there is no pending sub block,
			 * just proceed to closing out.
			 */

			if (later == NULL)
				break;

			/*
			 * When there is a pending sub block,
			 * postpone closing out the current block
			 * until the rew_sub() closing out the sub-block.
			 */

			make_pending(later, tok, mdoc, line, ppos);

			/*
			 * Mark the place where the formatting - but not
			 * the scope - of the current block ends.
			 */

			mdoc_endbody_alloc(mdoc, line, ppos,
			    atok, body, ENDBODY_SPACE);

			/*
			 * If a block closing macro taking arguments
			 * breaks another block, put the arguments
			 * into the end marker and remeber the
			 * end marker in order to close it out.
			 */

			if (maxargs) {
				endbody = mdoc->last;
				mdoc->next = MDOC_NEXT_CHILD;
			}
			break;
		}

		/*
		 * When finding an open sub block, remember the last
		 * open explicit block, or, in case there are only
		 * implicit ones, the first open implicit block.
		 */

		if (later &&
		    mdoc_macros[later->tok].flags & MDOC_EXPLICIT)
			continue;
		if (n->tok != MDOC_It)
			later = n;
	}
	rew_sub(MDOC_BODY, mdoc, tok, line, ppos);

	if ( ! (mdoc_macros[tok].flags & MDOC_PARSED)) {
		if (buf[*pos] != '\0')
			mandoc_vmsg(MANDOCERR_ARG_SKIP,
			    mdoc->parse, line, ppos,
			    "%s %s", mdoc_macronames[tok],
			    buf + *pos);
		rew_sub(MDOC_BLOCK, mdoc, tok, line, ppos);
		return;
	}

	if (maxargs && endbody == NULL) {
		if (n == NULL) {
			/*
			 * Stray .Ec without previous .Eo:
			 * Break the output line, ignore any arguments.
			 */
			mdoc_elem_alloc(mdoc, line, ppos, MDOC_br, NULL);
			rew_elem(mdoc, MDOC_br);
		} else
			mdoc_tail_alloc(mdoc, line, ppos, atok);
	}

	flushed = n == NULL;
	for (j = 0; ; j++) {
		lastarg = *pos;

		if (j == maxargs && ! flushed) {
			if (endbody == NULL)
				rew_sub(MDOC_BLOCK, mdoc, tok, line, ppos);
			else
				rew_last(mdoc, endbody);
			flushed = 1;
		}

		ac = mdoc_args(mdoc, line, pos, buf, tok, &p);
		if (ac == ARGS_PUNCT || ac == ARGS_EOLN)
			break;

		ntok = ac == ARGS_QWORD ? MDOC_MAX :
		    lookup(mdoc, tok, line, lastarg, p);

		if (ntok == MDOC_MAX) {
			dword(mdoc, line, lastarg, p, DELIM_MAX,
			    MDOC_JOIN & mdoc_macros[tok].flags);
			continue;
		}

		if ( ! flushed) {
			if (endbody == NULL)
				rew_sub(MDOC_BLOCK, mdoc, tok, line, ppos);
			else
				rew_last(mdoc, endbody);
			flushed = 1;
		}
		mdoc->flags &= ~MDOC_NEWLINE;
		mdoc_macro(mdoc, ntok, line, lastarg, pos, buf);
		break;
	}

	if ( ! flushed) {
		if (endbody == NULL)
			rew_sub(MDOC_BLOCK, mdoc, tok, line, ppos);
		else
			rew_last(mdoc, endbody);
	}
	if (nl)
		append_delims(mdoc, line, pos, buf);
}

static void
in_line(MACRO_PROT_ARGS)
{
	int		 la, scope, cnt, firstarg, mayopen, nc, nl;
	enum mdoct	 ntok;
	enum margserr	 ac;
	enum mdelim	 d;
	struct mdoc_arg	*arg;
	char		*p;

	nl = MDOC_NEWLINE & mdoc->flags;

	/*
	 * Whether we allow ignored elements (those without content,
	 * usually because of reserved words) to squeak by.
	 */

	switch (tok) {
	case MDOC_An:
		/* FALLTHROUGH */
	case MDOC_Ar:
		/* FALLTHROUGH */
	case MDOC_Fl:
		/* FALLTHROUGH */
	case MDOC_Mt:
		/* FALLTHROUGH */
	case MDOC_Nm:
		/* FALLTHROUGH */
	case MDOC_Pa:
		nc = 1;
		break;
	default:
		nc = 0;
		break;
	}

	mdoc_argv(mdoc, line, tok, &arg, pos, buf);

	d = DELIM_NONE;
	firstarg = 1;
	mayopen = 1;
	for (cnt = scope = 0;; ) {
		la = *pos;
		ac = mdoc_args(mdoc, line, pos, buf, tok, &p);

		/*
		 * At the end of a macro line,
		 * opening delimiters do not suppress spacing.
		 */

		if (ac == ARGS_EOLN) {
			if (d == DELIM_OPEN)
				mdoc->last->flags &= ~MDOC_DELIMO;
			break;
		}

		/*
		 * The rest of the macro line is only punctuation,
		 * to be handled by append_delims().
		 * If there were no other arguments,
		 * do not allow the first one to suppress spacing,
		 * even if it turns out to be a closing one.
		 */

		if (ac == ARGS_PUNCT) {
			if (cnt == 0 && nc == 0)
				mdoc->flags |= MDOC_NODELIMC;
			break;
		}

		ntok = (ac == ARGS_QWORD || (tok == MDOC_Fn && !cnt)) ?
		    MDOC_MAX : lookup(mdoc, tok, line, la, p);

		/*
		 * In this case, we've located a submacro and must
		 * execute it.  Close out scope, if open.  If no
		 * elements have been generated, either create one (nc)
		 * or raise a warning.
		 */

		if (ntok != MDOC_MAX) {
			if (scope)
				rew_elem(mdoc, tok);
			if (nc && ! cnt) {
				mdoc_elem_alloc(mdoc, line, ppos, tok, arg);
				rew_last(mdoc, mdoc->last);
			} else if ( ! nc && ! cnt) {
				mdoc_argv_free(arg);
				mandoc_msg(MANDOCERR_MACRO_EMPTY,
				    mdoc->parse, line, ppos,
				    mdoc_macronames[tok]);
			}
			mdoc_macro(mdoc, ntok, line, la, pos, buf);
			if (nl)
				append_delims(mdoc, line, pos, buf);
			return;
		}

		/*
		 * Non-quote-enclosed punctuation.  Set up our scope, if
		 * a word; rewind the scope, if a delimiter; then append
		 * the word.
		 */

		d = ac == ARGS_QWORD ? DELIM_NONE : mdoc_isdelim(p);

		if (DELIM_NONE != d) {
			/*
			 * If we encounter closing punctuation, no word
			 * has been emitted, no scope is open, and we're
			 * allowed to have an empty element, then start
			 * a new scope.
			 */
			if ((d == DELIM_CLOSE ||
			     (d == DELIM_MIDDLE && tok == MDOC_Fl)) &&
			    !cnt && !scope && nc && mayopen) {
				mdoc_elem_alloc(mdoc, line, ppos, tok, arg);
				scope = 1;
				cnt++;
				if (tok == MDOC_Nm)
					mayopen = 0;
			}
			/*
			 * Close out our scope, if one is open, before
			 * any punctuation.
			 */
			if (scope)
				rew_elem(mdoc, tok);
			scope = 0;
			if (tok == MDOC_Fn)
				mayopen = 0;
		} else if (mayopen && !scope) {
			mdoc_elem_alloc(mdoc, line, ppos, tok, arg);
			scope = 1;
			cnt++;
		}

		dword(mdoc, line, la, p, d,
		    MDOC_JOIN & mdoc_macros[tok].flags);

		/*
		 * If the first argument is a closing delimiter,
		 * do not suppress spacing before it.
		 */

		if (firstarg && d == DELIM_CLOSE && !nc)
			mdoc->last->flags &= ~MDOC_DELIMC;
		firstarg = 0;

		/*
		 * `Fl' macros have their scope re-opened with each new
		 * word so that the `-' can be added to each one without
		 * having to parse out spaces.
		 */
		if (scope && tok == MDOC_Fl) {
			rew_elem(mdoc, tok);
			scope = 0;
		}
	}

	if (scope)
		rew_elem(mdoc, tok);

	/*
	 * If no elements have been collected and we're allowed to have
	 * empties (nc), open a scope and close it out.  Otherwise,
	 * raise a warning.
	 */

	if ( ! cnt) {
		if (nc) {
			mdoc_elem_alloc(mdoc, line, ppos, tok, arg);
			rew_last(mdoc, mdoc->last);
		} else {
			mdoc_argv_free(arg);
			mandoc_msg(MANDOCERR_MACRO_EMPTY, mdoc->parse,
			    line, ppos, mdoc_macronames[tok]);
		}
	}
	if (nl)
		append_delims(mdoc, line, pos, buf);
}

static void
blk_full(MACRO_PROT_ARGS)
{
	int		  la, nl, parsed;
	struct mdoc_arg	 *arg;
	struct mdoc_node *head; /* save of head macro */
	struct mdoc_node *body; /* save of body macro */
	struct mdoc_node *n;
	enum margserr	  ac, lac;
	char		 *p;

	nl = MDOC_NEWLINE & mdoc->flags;

	/* Skip items outside lists. */

	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)))
				break;
		if (n == NULL) {
			mandoc_vmsg(MANDOCERR_IT_STRAY, mdoc->parse,
			    line, ppos, "It %s", buf + *pos);
			mdoc_elem_alloc(mdoc, line, ppos, MDOC_br, NULL);
			rew_elem(mdoc, MDOC_br);
			return;
		}
	}

	/* 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
	 * (seen above).  Delay opening the head until necessary to
	 * allow leading punctuation to print.  Special consideration
	 * for `It -column', which has phrase-part syntax instead of
	 * regular child nodes.
	 */

	mdoc_argv(mdoc, line, tok, &arg, pos, buf);
	mdoc_block_alloc(mdoc, line, ppos, tok, arg);
	head = body = NULL;

	/*
	 * Exception: Heads of `It' macros in `-diag' lists are not
	 * parsed, even though `It' macros in general are parsed.
	 */

	parsed = tok != MDOC_It ||
	    mdoc->last->parent->tok != MDOC_Bl ||
	    mdoc->last->parent->norm->Bl.type != LIST_diag;

	/*
	 * The `Nd' macro has all arguments in its body: it's a hybrid
	 * of block partial-explicit and full-implicit.  Stupid.
	 */

	if (tok == MDOC_Nd) {
		head = mdoc_head_alloc(mdoc, line, ppos, tok);
		rew_sub(MDOC_HEAD, mdoc, tok, line, ppos);
		body = mdoc_body_alloc(mdoc, line, ppos, tok);
	}

	if (tok == MDOC_Bk)
		mdoc->flags |= MDOC_KEEP;

	ac = ARGS_PEND;
	for (;;) {
		la = *pos;
		lac = ac;
		ac = mdoc_args(mdoc, line, pos, buf, tok, &p);
		if (ac == ARGS_PUNCT)
			break;
		if (ac == ARGS_EOLN) {
			if (lac != ARGS_PPHRASE && lac != ARGS_PHRASE)
				break;
			/*
			 * This is necessary: if the last token on a
			 * line is a `Ta' or tab, then we'll get
			 * ARGS_EOLN, so we must be smart enough to
			 * reopen our scope if the last parse was a
			 * phrase or partial phrase.
			 */
			rew_sub(MDOC_BODY, mdoc, tok, line, ppos);
			body = mdoc_body_alloc(mdoc, line, ppos, tok);
			break;
		}

		/*
		 * Emit leading punctuation (i.e., punctuation before
		 * the MDOC_HEAD) for non-phrase types.
		 */

		if (head == NULL &&
		    ac != ARGS_PEND &&
		    ac != ARGS_PHRASE &&
		    ac != ARGS_PPHRASE &&
		    ac != ARGS_QWORD &&
		    mdoc_isdelim(p) == DELIM_OPEN) {
			dword(mdoc, line, la, p, DELIM_OPEN, 0);
			continue;
		}

		/* Open a head if one hasn't been opened. */

		if (head == NULL)
			head = mdoc_head_alloc(mdoc, line, ppos, tok);

		if (ac == ARGS_PHRASE ||
		    ac == ARGS_PEND ||
		    ac == ARGS_PPHRASE) {

			/*
			 * If we haven't opened a body yet, rewind the
			 * head; if we have, rewind that instead.
			 */

			rew_sub(body ? MDOC_BODY : MDOC_HEAD,
			    mdoc, tok, line, ppos);
			body = mdoc_body_alloc(mdoc, line, ppos, tok);

			/*
			 * Process phrases: set whether we're in a
			 * partial-phrase (this effects line handling)
			 * then call down into the phrase parser.
			 */

			if (ac == ARGS_PPHRASE)
				mdoc->flags |= MDOC_PPHRASE;
			if (ac == ARGS_PEND && lac == ARGS_PPHRASE)
				mdoc->flags |= MDOC_PPHRASE;
			parse_rest(mdoc, MDOC_MAX, line, &la, buf);
			mdoc->flags &= ~MDOC_PPHRASE;
			continue;
		}

		if (macro_or_word(mdoc, tok, line, la, pos, buf, parsed))
			break;
	}

	if (head == NULL)
		head = mdoc_head_alloc(mdoc, line, ppos, tok);
	if (nl)
		append_delims(mdoc, line, pos, buf);
	if (body != NULL)
		goto out;

	/*
	 * If there is an open (i.e., unvalidated) sub-block requiring
	 * explicit close-out, postpone switching the current block from
	 * head to body until the rew_sub() call closing out that
	 * sub-block.
	 */
	for (n = mdoc->last; n && n != head; n = n->parent) {
		if (n->type == MDOC_BLOCK &&
		    mdoc_macros[n->tok].flags & MDOC_EXPLICIT &&
		    ! (n->flags & MDOC_VALID)) {
			n->pending = head;
			return;
		}
	}

	/* Close out scopes to remain in a consistent state. */

	rew_sub(MDOC_HEAD, mdoc, tok, line, ppos);
	mdoc_body_alloc(mdoc, line, ppos, tok);
out:
	if (mdoc->flags & MDOC_FREECOL) {
		rew_sub(MDOC_BODY, mdoc, tok, line, ppos);
		rew_sub(MDOC_BLOCK, mdoc, tok, line, ppos);
		mdoc->flags &= ~MDOC_FREECOL;
	}
}

static void
blk_part_imp(MACRO_PROT_ARGS)
{
	int		  la, nl;
	enum margserr	  ac;
	char		 *p;
	struct mdoc_node *blk; /* saved block context */
	struct mdoc_node *body; /* saved body context */
	struct mdoc_node *n;

	nl = MDOC_NEWLINE & mdoc->flags;

	/*
	 * A macro that spans to the end of the line.  This is generally
	 * (but not necessarily) called as the first macro.  The block
	 * has a head as the immediate child, which is always empty,
	 * followed by zero or more opening punctuation nodes, then the
	 * body (which may be empty, depending on the macro), then zero
	 * or more closing punctuation nodes.
	 */

	blk = mdoc_block_alloc(mdoc, line, ppos, tok, NULL);
	mdoc_head_alloc(mdoc, line, ppos, tok);
	rew_sub(MDOC_HEAD, mdoc, tok, line, ppos);

	/*
	 * Open the body scope "on-demand", that is, after we've
	 * processed all our the leading delimiters (open parenthesis,
	 * etc.).
	 */

	for (body = NULL; ; ) {
		la = *pos;
		ac = mdoc_args(mdoc, line, pos, buf, tok, &p);
		if (ac == ARGS_EOLN || ac == ARGS_PUNCT)
			break;

		if (body == NULL && ac != ARGS_QWORD &&
		    mdoc_isdelim(p) == DELIM_OPEN) {
			dword(mdoc, line, la, p, DELIM_OPEN, 0);
			continue;
		}

		if (body == NULL)
			body = mdoc_body_alloc(mdoc, line, ppos, tok);

		if (macro_or_word(mdoc, tok, line, la, pos, buf, 1))
			break;
	}
	if (body == NULL)
		body = mdoc_body_alloc(mdoc, line, ppos, tok);

	/*
	 * If there is an open sub-block requiring explicit close-out,
	 * postpone closing out the current block
	 * until the rew_sub() call closing out the sub-block.
	 */

	for (n = mdoc->last; n && n != body && n != blk->parent;
	     n = n->parent) {
		if (n->type == MDOC_BLOCK &&
		    mdoc_macros[n->tok].flags & MDOC_EXPLICIT &&
		    ! (n->flags & MDOC_VALID)) {
			make_pending(n, tok, mdoc, line, ppos);
			mdoc_endbody_alloc(mdoc, line, ppos,
			    tok, body, ENDBODY_NOSPACE);
			return;
		}
	}
	assert(n == body);
	rew_sub(MDOC_BODY, mdoc, tok, line, ppos);
	if (nl)
		append_delims(mdoc, line, pos, buf);
	rew_sub(MDOC_BLOCK, mdoc, tok, line, ppos);

	/* Move trailing .Ns out of scope. */

	for (n = body->child; n && n->next; n = n->next)
		/* Do nothing. */ ;
	if (n && n->tok == MDOC_Ns)
		mdoc_node_relink(mdoc, n);
}

static void
blk_part_exp(MACRO_PROT_ARGS)
{
	int		  la, nl;
	enum margserr	  ac;
	struct mdoc_node *head; /* keep track of head */
	struct mdoc_node *body; /* keep track of body */
	char		 *p;

	nl = MDOC_NEWLINE & mdoc->flags;

	/*
	 * The opening of an explicit macro having zero or more leading
	 * punctuation nodes; a head with optional single element (the
	 * case of `Eo'); and a body that may be empty.
	 */

	mdoc_block_alloc(mdoc, line, ppos, tok, NULL);
	for (head = body = NULL; ; ) {
		la = *pos;
		ac = mdoc_args(mdoc, line, pos, buf, tok, &p);
		if (ac == ARGS_PUNCT || ac == ARGS_EOLN)
			break;

		/* Flush out leading punctuation. */

		if (head == NULL && ac != ARGS_QWORD &&
		    mdoc_isdelim(p) == DELIM_OPEN) {
			assert(NULL == body);
			dword(mdoc, line, la, p, DELIM_OPEN, 0);
			continue;
		}

		if (head == NULL) {
			assert(body == NULL);
			head = mdoc_head_alloc(mdoc, line, ppos, tok);
		}

		/*
		 * `Eo' gobbles any data into the head, but most other
		 * macros just immediately close out and begin the body.
		 */

		if (body == NULL) {
			assert(head);
			/* No check whether it's a macro! */
			if (tok == MDOC_Eo)
				dword(mdoc, line, la, p, DELIM_MAX, 0);
			rew_sub(MDOC_HEAD, mdoc, tok, line, ppos);
			body = mdoc_body_alloc(mdoc, line, ppos, tok);
			if (tok == MDOC_Eo)
				continue;
		}
		assert(head != NULL && body != NULL);

		if (macro_or_word(mdoc, tok, line, la, pos, buf, 1))
			break;
	}

	/* Clean-up to leave in a consistent state. */

	if (head == NULL)
		mdoc_head_alloc(mdoc, line, ppos, tok);

	if (body == NULL) {
		rew_sub(MDOC_HEAD, mdoc, tok, line, ppos);
		mdoc_body_alloc(mdoc, line, ppos, tok);
	}
	if (nl)
		append_delims(mdoc, line, pos, buf);
}

static void
in_line_argn(MACRO_PROT_ARGS)
{
	int		 la, flushed, j, maxargs, nl;
	enum margserr	 ac;
	struct mdoc_arg	*arg;
	char		*p;
	enum mdoct	 ntok;

	nl = mdoc->flags & MDOC_NEWLINE;

	/*
	 * A line macro that has a fixed number of arguments (maxargs).
	 * Only open the scope once the first non-leading-punctuation is
	 * found (unless MDOC_IGNDELIM is noted, like in `Pf'), then
	 * keep it open until the maximum number of arguments are
	 * exhausted.
	 */

	switch (tok) {
	case MDOC_Ap:
		/* FALLTHROUGH */
	case MDOC_Ns:
		/* FALLTHROUGH */
	case MDOC_Ux:
		maxargs = 0;
		break;
	case MDOC_Bx:
		/* FALLTHROUGH */
	case MDOC_Es:
		/* FALLTHROUGH */
	case MDOC_Xr:
		maxargs = 2;
		break;
	default:
		maxargs = 1;
		break;
	}

	mdoc_argv(mdoc, line, tok, &arg, pos, buf);

	p = NULL;
	flushed = j = 0;
	for (;;) {
		la = *pos;
		ac = mdoc_args(mdoc, line, pos, buf, tok, &p);
		if (ac == ARGS_PUNCT || ac == ARGS_EOLN) {
			if (j < 2 && tok == MDOC_Pf)
				mandoc_vmsg(MANDOCERR_PF_SKIP,
				    mdoc->parse, line, ppos, "Pf %s",
				    p == NULL ? "at eol" : p);
			break;
		}

		if ( ! (mdoc_macros[tok].flags & MDOC_IGNDELIM) &&
		    ac != ARGS_QWORD && j == 0 &&
		    mdoc_isdelim(p) == DELIM_OPEN) {
			dword(mdoc, line, la, p, DELIM_OPEN, 0);
			continue;
		} else if (j == 0)
		       mdoc_elem_alloc(mdoc, line, ppos, tok, arg);

		if (j == maxargs && ! flushed) {
			rew_elem(mdoc, tok);
			flushed = 1;
		}

		ntok = (ac == ARGS_QWORD || (tok == MDOC_Pf && j == 0)) ?
		    MDOC_MAX : lookup(mdoc, tok, line, la, p);

		if (ntok != MDOC_MAX) {
			if ( ! flushed)
				rew_elem(mdoc, tok);
			flushed = 1;
			mdoc_macro(mdoc, ntok, line, la, pos, buf);
			j++;
			break;
		}

		if ( ! (mdoc_macros[tok].flags & MDOC_IGNDELIM) &&
		    ac != ARGS_QWORD && ! flushed &&
		    mdoc_isdelim(p) != DELIM_NONE) {
			rew_elem(mdoc, tok);
			flushed = 1;
		}

		dword(mdoc, line, la, p, DELIM_MAX,
		    MDOC_JOIN & mdoc_macros[tok].flags);
		j++;
	}

	if (j == 0) {
		mdoc_elem_alloc(mdoc, line, ppos, tok, arg);
		if (ac == ARGS_PUNCT && tok == MDOC_Pf)
			append_delims(mdoc, line, pos, buf);
	}
	if ( ! flushed)
		rew_elem(mdoc, tok);
	if (nl)
		append_delims(mdoc, line, pos, buf);
}

static void
in_line_eoln(MACRO_PROT_ARGS)
{
	struct mdoc_arg	*arg;

	if (tok == MDOC_Pp)
		rew_sub(MDOC_BLOCK, mdoc, MDOC_Nm, line, ppos);

	mdoc_argv(mdoc, line, tok, &arg, pos, buf);
	mdoc_elem_alloc(mdoc, line, ppos, tok, arg);
	if (parse_rest(mdoc, tok, line, pos, buf))
		return;
	rew_elem(mdoc, tok);
}

/*
 * The simplest argument parser available: Parse the remaining
 * words until the end of the phrase or line and return 0
 * or until the next macro, call that macro, and return 1.
 */
static int
parse_rest(struct mdoc *mdoc, enum mdoct tok, int line, int *pos, char *buf)
{
	int		 la;

	for (;;) {
		la = *pos;
		if (mdoc_args(mdoc, line, pos, buf, tok, NULL) == ARGS_EOLN)
			return(0);
		if (macro_or_word(mdoc, tok, line, la, pos, buf, 1))
			return(1);
	}
}

static void
ctx_synopsis(MACRO_PROT_ARGS)
{

	if (~mdoc->flags & (MDOC_SYNOPSIS | MDOC_NEWLINE))
		in_line(mdoc, tok, line, ppos, pos, buf);
	else if (tok == MDOC_Nm)
		blk_full(mdoc, tok, line, ppos, pos, buf);
	else {
		assert(tok == MDOC_Vt);
		blk_part_imp(mdoc, tok, line, ppos, pos, buf);
	}
}

/*
 * Phrases occur within `Bl -column' entries, separated by `Ta' or tabs.
 * They're unusual because they're basically free-form text until a
 * macro is encountered.
 */
static void
phrase_ta(MACRO_PROT_ARGS)
{
	struct mdoc_node *n;

	/* Make sure we are in a column list or ignore this macro. */

	n = mdoc->last;
	while (n != NULL && n->tok != MDOC_Bl)
		n = n->parent;
	if (n == NULL || n->norm->Bl.type != LIST_column) {
		mandoc_msg(MANDOCERR_TA_STRAY, mdoc->parse,
		    line, ppos, "Ta");
		return;
	}

	/* Advance to the next column. */

	rew_sub(MDOC_BODY, mdoc, MDOC_It, line, ppos);
	mdoc_body_alloc(mdoc, line, ppos, MDOC_It);
	parse_rest(mdoc, MDOC_MAX, line, pos, buf);
}