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

Revision 1.196, Fri Sep 30 00:13:28 2011 UTC (12 years, 6 months ago) by schwarze
Branch: MAIN
CVS Tags: VERSION_1_12_1, VERSION_1_12_0
Changes since 1.195: +2 -1 lines

implement .Ap .Bd .Bo .Bq .D1 .Ic .Lp .Oo .Pf .Po .Ss .Sx .Sy .br .sp
implement .Bl -bullet
add more information to the .TH line
escape dots at the beginnings of lines
add trailing newline character at the end of the file
do not misinterpret the ROOT block as .Ap

/*	$Id: mdoc.c,v 1.196 2011/09/30 00:13:28 schwarze Exp $ */
/*
 * Copyright (c) 2008, 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2010 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.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <sys/types.h>

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

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

const	char *const __mdoc_macronames[MDOC_MAX] = {		 
	"Ap",		"Dd",		"Dt",		"Os",
	"Sh",		"Ss",		"Pp",		"D1",
	"Dl",		"Bd",		"Ed",		"Bl",
	"El",		"It",		"Ad",		"An",
	"Ar",		"Cd",		"Cm",		"Dv",
	"Er",		"Ev",		"Ex",		"Fa",
	"Fd",		"Fl",		"Fn",		"Ft",
	"Ic",		"In",		"Li",		"Nd",
	"Nm",		"Op",		"Ot",		"Pa",
	"Rv",		"St",		"Va",		"Vt",
	/* LINTED */
	"Xr",		"%A",		"%B",		"%D",
	/* LINTED */
	"%I",		"%J",		"%N",		"%O",
	/* LINTED */
	"%P",		"%R",		"%T",		"%V",
	"Ac",		"Ao",		"Aq",		"At",
	"Bc",		"Bf",		"Bo",		"Bq",
	"Bsx",		"Bx",		"Db",		"Dc",
	"Do",		"Dq",		"Ec",		"Ef",
	"Em",		"Eo",		"Fx",		"Ms",
	"No",		"Ns",		"Nx",		"Ox",
	"Pc",		"Pf",		"Po",		"Pq",
	"Qc",		"Ql",		"Qo",		"Qq",
	"Re",		"Rs",		"Sc",		"So",
	"Sq",		"Sm",		"Sx",		"Sy",
	"Tn",		"Ux",		"Xc",		"Xo",
	"Fo",		"Fc",		"Oo",		"Oc",
	"Bk",		"Ek",		"Bt",		"Hf",
	"Fr",		"Ud",		"Lb",		"Lp",
	"Lk",		"Mt",		"Brq",		"Bro",
	/* LINTED */
	"Brc",		"%C",		"Es",		"En",
	/* LINTED */
	"Dx",		"%Q",		"br",		"sp",
	/* LINTED */
	"%U",		"Ta"
	};

const	char *const __mdoc_argnames[MDOC_ARG_MAX] = {		 
	"split",		"nosplit",		"ragged",
	"unfilled",		"literal",		"file",		 
	"offset",		"bullet",		"dash",		 
	"hyphen",		"item",			"enum",		 
	"tag",			"diag",			"hang",		 
	"ohang",		"inset",		"column",	 
	"width",		"compact",		"std",	 
	"filled",		"words",		"emphasis",
	"symbolic",		"nested",		"centered"
	};

const	char * const *mdoc_macronames = __mdoc_macronames;
const	char * const *mdoc_argnames = __mdoc_argnames;

static	void		  mdoc_node_free(struct mdoc_node *);
static	void		  mdoc_node_unlink(struct mdoc *, 
				struct mdoc_node *);
static	void		  mdoc_free1(struct mdoc *);
static	void		  mdoc_alloc1(struct mdoc *);
static	struct mdoc_node *node_alloc(struct mdoc *, int, int, 
				enum mdoct, enum mdoc_type);
static	int		  node_append(struct mdoc *, 
				struct mdoc_node *);
#if 0
static	int		  mdoc_preptext(struct mdoc *, int, char *, int);
#endif
static	int		  mdoc_ptext(struct mdoc *, int, char *, int);
static	int		  mdoc_pmacro(struct mdoc *, int, char *, int);

const struct mdoc_node *
mdoc_node(const struct mdoc *m)
{

	assert( ! (MDOC_HALT & m->flags));
	return(m->first);
}


const struct mdoc_meta *
mdoc_meta(const struct mdoc *m)
{

	assert( ! (MDOC_HALT & m->flags));
	return(&m->meta);
}


/*
 * Frees volatile resources (parse tree, meta-data, fields).
 */
static void
mdoc_free1(struct mdoc *mdoc)
{

	if (mdoc->first)
		mdoc_node_delete(mdoc, mdoc->first);
	if (mdoc->meta.title)
		free(mdoc->meta.title);
	if (mdoc->meta.os)
		free(mdoc->meta.os);
	if (mdoc->meta.name)
		free(mdoc->meta.name);
	if (mdoc->meta.arch)
		free(mdoc->meta.arch);
	if (mdoc->meta.vol)
		free(mdoc->meta.vol);
	if (mdoc->meta.msec)
		free(mdoc->meta.msec);
	if (mdoc->meta.date)
		free(mdoc->meta.date);
}


/*
 * Allocate all volatile resources (parse tree, meta-data, fields).
 */
static void
mdoc_alloc1(struct mdoc *mdoc)
{

	memset(&mdoc->meta, 0, sizeof(struct mdoc_meta));
	mdoc->flags = 0;
	mdoc->lastnamed = mdoc->lastsec = SEC_NONE;
	mdoc->last = mandoc_calloc(1, sizeof(struct mdoc_node));
	mdoc->first = mdoc->last;
	mdoc->last->type = MDOC_ROOT;
	mdoc->last->tok = MDOC_MAX;
	mdoc->next = MDOC_NEXT_CHILD;
}


/*
 * Free up volatile resources (see mdoc_free1()) then re-initialises the
 * data with mdoc_alloc1().  After invocation, parse data has been reset
 * and the parser is ready for re-invocation on a new tree; however,
 * cross-parse non-volatile data is kept intact.
 */
void
mdoc_reset(struct mdoc *mdoc)
{

	mdoc_free1(mdoc);
	mdoc_alloc1(mdoc);
}


/*
 * Completely free up all volatile and non-volatile parse resources.
 * After invocation, the pointer is no longer usable.
 */
void
mdoc_free(struct mdoc *mdoc)
{

	mdoc_free1(mdoc);
	free(mdoc);
}


/*
 * Allocate volatile and non-volatile parse resources.  
 */
struct mdoc *
mdoc_alloc(struct roff *roff, struct mparse *parse)
{
	struct mdoc	*p;

	p = mandoc_calloc(1, sizeof(struct mdoc));

	p->parse = parse;
	p->roff = roff;

	mdoc_hash_init();
	mdoc_alloc1(p);
	return(p);
}


/*
 * Climb back up the parse tree, validating open scopes.  Mostly calls
 * through to macro_end() in macro.c.
 */
int
mdoc_endparse(struct mdoc *m)
{

	assert( ! (MDOC_HALT & m->flags));
	if (mdoc_macroend(m))
		return(1);
	m->flags |= MDOC_HALT;
	return(0);
}

int
mdoc_addeqn(struct mdoc *m, const struct eqn *ep)
{
	struct mdoc_node *n;

	assert( ! (MDOC_HALT & m->flags));

	/* No text before an initial macro. */

	if (SEC_NONE == m->lastnamed) {
		mdoc_pmsg(m, ep->ln, ep->pos, MANDOCERR_NOTEXT);
		return(1);
	}

	n = node_alloc(m, ep->ln, ep->pos, MDOC_MAX, MDOC_EQN);
	n->eqn = ep;

	if ( ! node_append(m, n))
		return(0);

	m->next = MDOC_NEXT_SIBLING;
	return(1);
}

int
mdoc_addspan(struct mdoc *m, const struct tbl_span *sp)
{
	struct mdoc_node *n;

	assert( ! (MDOC_HALT & m->flags));

	/* No text before an initial macro. */

	if (SEC_NONE == m->lastnamed) {
		mdoc_pmsg(m, sp->line, 0, MANDOCERR_NOTEXT);
		return(1);
	}

	n = node_alloc(m, sp->line, 0, MDOC_MAX, MDOC_TBL);
	n->span = sp;

	if ( ! node_append(m, n))
		return(0);

	m->next = MDOC_NEXT_SIBLING;
	return(1);
}


/*
 * Main parse routine.  Parses a single line -- really just hands off to
 * the macro (mdoc_pmacro()) or text parser (mdoc_ptext()).
 */
int
mdoc_parseln(struct mdoc *m, int ln, char *buf, int offs)
{

	assert( ! (MDOC_HALT & m->flags));

	m->flags |= MDOC_NEWLINE;

	/*
	 * Let the roff nS register switch SYNOPSIS mode early,
	 * such that the parser knows at all times
	 * whether this mode is on or off.
	 * Note that this mode is also switched by the Sh macro.
	 */
	if (roff_regisset(m->roff, REG_nS)) {
		if (roff_regget(m->roff, REG_nS))
			m->flags |= MDOC_SYNOPSIS;
		else
			m->flags &= ~MDOC_SYNOPSIS;
	}

	return(mandoc_getcontrol(buf, &offs) ?
			mdoc_pmacro(m, ln, buf, offs) :
			mdoc_ptext(m, ln, buf, offs));
}

int
mdoc_macro(MACRO_PROT_ARGS)
{
	assert(tok < MDOC_MAX);

	/* If we're in the body, deny prologue calls. */

	if (MDOC_PROLOGUE & mdoc_macros[tok].flags && 
			MDOC_PBODY & m->flags) {
		mdoc_pmsg(m, line, ppos, MANDOCERR_BADBODY);
		return(1);
	}

	/* If we're in the prologue, deny "body" macros.  */

	if ( ! (MDOC_PROLOGUE & mdoc_macros[tok].flags) && 
			! (MDOC_PBODY & m->flags)) {
		mdoc_pmsg(m, line, ppos, MANDOCERR_BADPROLOG);
		if (NULL == m->meta.msec)
			m->meta.msec = mandoc_strdup("1");
		if (NULL == m->meta.title)
			m->meta.title = mandoc_strdup("UNKNOWN");
		if (NULL == m->meta.vol)
			m->meta.vol = mandoc_strdup("LOCAL");
		if (NULL == m->meta.os)
			m->meta.os = mandoc_strdup("LOCAL");
		if (NULL == m->meta.date)
			m->meta.date = mandoc_normdate
				(m->parse, NULL, line, ppos);
		m->flags |= MDOC_PBODY;
	}

	return((*mdoc_macros[tok].fp)(m, tok, line, ppos, pos, buf));
}


static int
node_append(struct mdoc *mdoc, struct mdoc_node *p)
{

	assert(mdoc->last);
	assert(mdoc->first);
	assert(MDOC_ROOT != p->type);

	switch (mdoc->next) {
	case (MDOC_NEXT_SIBLING):
		mdoc->last->next = p;
		p->prev = mdoc->last;
		p->parent = mdoc->last->parent;
		break;
	case (MDOC_NEXT_CHILD):
		mdoc->last->child = p;
		p->parent = mdoc->last;
		break;
	default:
		abort();
		/* NOTREACHED */
	}

	p->parent->nchild++;

	/*
	 * Copy over the normalised-data pointer of our parent.  Not
	 * everybody has one, but copying a null pointer is fine.
	 */

	switch (p->type) {
	case (MDOC_BODY):
		/* FALLTHROUGH */
	case (MDOC_TAIL):
		/* FALLTHROUGH */
	case (MDOC_HEAD):
		p->norm = p->parent->norm;
		break;
	default:
		break;
	}

	if ( ! mdoc_valid_pre(mdoc, p))
		return(0);

	switch (p->type) {
	case (MDOC_HEAD):
		assert(MDOC_BLOCK == p->parent->type);
		p->parent->head = p;
		break;
	case (MDOC_TAIL):
		assert(MDOC_BLOCK == p->parent->type);
		p->parent->tail = p;
		break;
	case (MDOC_BODY):
		if (p->end)
			break;
		assert(MDOC_BLOCK == p->parent->type);
		p->parent->body = p;
		break;
	default:
		break;
	}

	mdoc->last = p;

	switch (p->type) {
	case (MDOC_TBL):
		/* FALLTHROUGH */
	case (MDOC_TEXT):
		if ( ! mdoc_valid_post(mdoc))
			return(0);
		break;
	default:
		break;
	}

	return(1);
}


static struct mdoc_node *
node_alloc(struct mdoc *m, int line, int pos, 
		enum mdoct tok, enum mdoc_type type)
{
	struct mdoc_node *p;

	p = mandoc_calloc(1, sizeof(struct mdoc_node));
	p->sec = m->lastsec;
	p->line = line;
	p->pos = pos;
	p->tok = tok;
	p->type = type;

	/* Flag analysis. */

	if (MDOC_SYNOPSIS & m->flags)
		p->flags |= MDOC_SYNPRETTY;
	else
		p->flags &= ~MDOC_SYNPRETTY;
	if (MDOC_NEWLINE & m->flags)
		p->flags |= MDOC_LINE;
	m->flags &= ~MDOC_NEWLINE;

	return(p);
}


int
mdoc_tail_alloc(struct mdoc *m, int line, int pos, enum mdoct tok)
{
	struct mdoc_node *p;

	p = node_alloc(m, line, pos, tok, MDOC_TAIL);
	if ( ! node_append(m, p))
		return(0);
	m->next = MDOC_NEXT_CHILD;
	return(1);
}


int
mdoc_head_alloc(struct mdoc *m, int line, int pos, enum mdoct tok)
{
	struct mdoc_node *p;

	assert(m->first);
	assert(m->last);

	p = node_alloc(m, line, pos, tok, MDOC_HEAD);
	if ( ! node_append(m, p))
		return(0);
	m->next = MDOC_NEXT_CHILD;
	return(1);
}


int
mdoc_body_alloc(struct mdoc *m, int line, int pos, enum mdoct tok)
{
	struct mdoc_node *p;

	p = node_alloc(m, line, pos, tok, MDOC_BODY);
	if ( ! node_append(m, p))
		return(0);
	m->next = MDOC_NEXT_CHILD;
	return(1);
}


int
mdoc_endbody_alloc(struct mdoc *m, int line, int pos, enum mdoct tok,
		struct mdoc_node *body, enum mdoc_endbody end)
{
	struct mdoc_node *p;

	p = node_alloc(m, line, pos, tok, MDOC_BODY);
	p->pending = body;
	p->end = end;
	if ( ! node_append(m, p))
		return(0);
	m->next = MDOC_NEXT_SIBLING;
	return(1);
}


int
mdoc_block_alloc(struct mdoc *m, int line, int pos, 
		enum mdoct tok, struct mdoc_arg *args)
{
	struct mdoc_node *p;

	p = node_alloc(m, line, pos, tok, MDOC_BLOCK);
	p->args = args;
	if (p->args)
		(args->refcnt)++;

	switch (tok) {
	case (MDOC_Bd):
		/* FALLTHROUGH */
	case (MDOC_Bf):
		/* FALLTHROUGH */
	case (MDOC_Bl):
		/* FALLTHROUGH */
	case (MDOC_Rs):
		p->norm = mandoc_calloc(1, sizeof(union mdoc_data));
		break;
	default:
		break;
	}

	if ( ! node_append(m, p))
		return(0);
	m->next = MDOC_NEXT_CHILD;
	return(1);
}


int
mdoc_elem_alloc(struct mdoc *m, int line, int pos, 
		enum mdoct tok, struct mdoc_arg *args)
{
	struct mdoc_node *p;

	p = node_alloc(m, line, pos, tok, MDOC_ELEM);
	p->args = args;
	if (p->args)
		(args->refcnt)++;

	switch (tok) {
	case (MDOC_An):
		p->norm = mandoc_calloc(1, sizeof(union mdoc_data));
		break;
	default:
		break;
	}

	if ( ! node_append(m, p))
		return(0);
	m->next = MDOC_NEXT_CHILD;
	return(1);
}

int
mdoc_word_alloc(struct mdoc *m, int line, int pos, const char *p)
{
	struct mdoc_node *n;

	n = node_alloc(m, line, pos, MDOC_MAX, MDOC_TEXT);
	n->string = roff_strdup(m->roff, p);

	if ( ! node_append(m, n))
		return(0);

	m->next = MDOC_NEXT_SIBLING;
	return(1);
}


static void
mdoc_node_free(struct mdoc_node *p)
{

	if (MDOC_BLOCK == p->type || MDOC_ELEM == p->type)
		free(p->norm);
	if (p->string)
		free(p->string);
	if (p->args)
		mdoc_argv_free(p->args);
	free(p);
}


static void
mdoc_node_unlink(struct mdoc *m, struct mdoc_node *n)
{

	/* Adjust siblings. */

	if (n->prev)
		n->prev->next = n->next;
	if (n->next)
		n->next->prev = n->prev;

	/* Adjust parent. */

	if (n->parent) {
		n->parent->nchild--;
		if (n->parent->child == n)
			n->parent->child = n->prev ? n->prev : n->next;
		if (n->parent->last == n)
			n->parent->last = n->prev ? n->prev : NULL;
	}

	/* Adjust parse point, if applicable. */

	if (m && m->last == n) {
		if (n->prev) {
			m->last = n->prev;
			m->next = MDOC_NEXT_SIBLING;
		} else {
			m->last = n->parent;
			m->next = MDOC_NEXT_CHILD;
		}
	}

	if (m && m->first == n)
		m->first = NULL;
}


void
mdoc_node_delete(struct mdoc *m, struct mdoc_node *p)
{

	while (p->child) {
		assert(p->nchild);
		mdoc_node_delete(m, p->child);
	}
	assert(0 == p->nchild);

	mdoc_node_unlink(m, p);
	mdoc_node_free(p);
}

#if 0
/*
 * Pre-treat a text line.
 * Text lines can consist of equations, which must be handled apart from
 * the regular text.
 * Thus, use this function to step through a line checking if it has any
 * equations embedded in it.
 * This must handle multiple equations AND equations that do not end at
 * the end-of-line, i.e., will re-enter in the next roff parse.
 */
static int
mdoc_preptext(struct mdoc *m, int line, char *buf, int offs)
{
	char		*start, *end;
	char		 delim;

	while ('\0' != buf[offs]) {
		/* Mark starting position if eqn is set. */
		start = NULL;
		if ('\0' != (delim = roff_eqndelim(m->roff)))
			if (NULL != (start = strchr(buf + offs, delim)))
				*start++ = '\0';

		/* Parse text as normal. */
		if ( ! mdoc_ptext(m, line, buf, offs))
			return(0);

		/* Continue only if an equation exists. */
		if (NULL == start)
			break;

		/* Read past the end of the equation. */
		offs += start - (buf + offs);
		assert(start == &buf[offs]);
		if (NULL != (end = strchr(buf + offs, delim))) {
			*end++ = '\0';
			while (' ' == *end)
				end++;
		}

		/* Parse the equation itself. */
		roff_openeqn(m->roff, NULL, line, offs, buf);

		/* Process a finished equation? */
		if (roff_closeeqn(m->roff))
			if ( ! mdoc_addeqn(m, roff_eqn(m->roff)))
				return(0);
		offs += (end - (buf + offs));
	} 

	return(1);
}
#endif

/*
 * Parse free-form text, that is, a line that does not begin with the
 * control character.
 */
static int
mdoc_ptext(struct mdoc *m, int line, char *buf, int offs)
{
	char		 *c, *ws, *end;
	struct mdoc_node *n;

	/* No text before an initial macro. */

	if (SEC_NONE == m->lastnamed) {
		mdoc_pmsg(m, line, offs, MANDOCERR_NOTEXT);
		return(1);
	}

	assert(m->last);
	n = m->last;

	/*
	 * Divert directly to list processing if we're encountering a
	 * columnar MDOC_BLOCK with or without a prior MDOC_BLOCK entry
	 * (a MDOC_BODY means it's already open, in which case we should
	 * process within its context in the normal way).
	 */

	if (MDOC_Bl == n->tok && MDOC_BODY == n->type &&
			LIST_column == n->norm->Bl.type) {
		/* `Bl' is open without any children. */
		m->flags |= MDOC_FREECOL;
		return(mdoc_macro(m, MDOC_It, line, offs, &offs, buf));
	}

	if (MDOC_It == n->tok && MDOC_BLOCK == n->type &&
			NULL != n->parent &&
			MDOC_Bl == n->parent->tok &&
			LIST_column == n->parent->norm->Bl.type) {
		/* `Bl' has block-level `It' children. */
		m->flags |= MDOC_FREECOL;
		return(mdoc_macro(m, MDOC_It, line, offs, &offs, buf));
	}

	/*
	 * Search for the beginning of unescaped trailing whitespace (ws)
	 * and for the first character not to be output (end).
	 */

	/* FIXME: replace with strcspn(). */
	ws = NULL;
	for (c = end = buf + offs; *c; c++) {
		switch (*c) {
		case ' ':
			if (NULL == ws)
				ws = c;
			continue;
		case '\t':
			/*
			 * Always warn about trailing tabs,
			 * even outside literal context,
			 * where they should be put on the next line.
			 */
			if (NULL == ws)
				ws = c;
			/*
			 * Strip trailing tabs in literal context only;
			 * outside, they affect the next line.
			 */
			if (MDOC_LITERAL & m->flags)
				continue;
			break;
		case '\\':
			/* Skip the escaped character, too, if any. */
			if (c[1])
				c++;
			/* FALLTHROUGH */
		default:
			ws = NULL;
			break;
		}
		end = c + 1;
	}
	*end = '\0';

	if (ws)
		mdoc_pmsg(m, line, (int)(ws-buf), MANDOCERR_EOLNSPACE);

	if ('\0' == buf[offs] && ! (MDOC_LITERAL & m->flags)) {
		mdoc_pmsg(m, line, (int)(c-buf), MANDOCERR_NOBLANKLN);

		/*
		 * Insert a `sp' in the case of a blank line.  Technically,
		 * blank lines aren't allowed, but enough manuals assume this
		 * behaviour that we want to work around it.
		 */
		if ( ! mdoc_elem_alloc(m, line, offs, MDOC_sp, NULL))
			return(0);

		m->next = MDOC_NEXT_SIBLING;
		return(1);
	}

	if ( ! mdoc_word_alloc(m, line, offs, buf+offs))
		return(0);

	if (MDOC_LITERAL & m->flags)
		return(1);

	/*
	 * End-of-sentence check.  If the last character is an unescaped
	 * EOS character, then flag the node as being the end of a
	 * sentence.  The front-end will know how to interpret this.
	 */

	assert(buf < end);

	if (mandoc_eos(buf+offs, (size_t)(end-buf-offs), 0))
		m->last->flags |= MDOC_EOS;

	return(1);
}


/*
 * Parse a macro line, that is, a line beginning with the control
 * character.
 */
static int
mdoc_pmacro(struct mdoc *m, int ln, char *buf, int offs)
{
	enum mdoct	  tok;
	int		  i, sv;
	char		  mac[5];
	struct mdoc_node *n;

	/* Empty post-control lines are ignored. */

	if ('"' == buf[offs]) {
		mdoc_pmsg(m, ln, offs, MANDOCERR_BADCOMMENT);
		return(1);
	} else if ('\0' == buf[offs])
		return(1);

	sv = offs;

	/* 
	 * Copy the first word into a nil-terminated buffer.
	 * Stop copying when a tab, space, or eoln is encountered.
	 */

	i = 0;
	while (i < 4 && '\0' != buf[offs] && 
			' ' != buf[offs] && '\t' != buf[offs])
		mac[i++] = buf[offs++];

	mac[i] = '\0';

	tok = (i > 1 || i < 4) ? mdoc_hash_find(mac) : MDOC_MAX;

	if (MDOC_MAX == tok) {
		mandoc_vmsg(MANDOCERR_MACRO, m->parse, 
				ln, sv, "%s", buf + sv - 1);
		return(1);
	}

	/* Disregard the first trailing tab, if applicable. */

	if ('\t' == buf[offs])
		offs++;

	/* Jump to the next non-whitespace word. */

	while (buf[offs] && ' ' == buf[offs])
		offs++;

	/* 
	 * Trailing whitespace.  Note that tabs are allowed to be passed
	 * into the parser as "text", so we only warn about spaces here.
	 */

	if ('\0' == buf[offs] && ' ' == buf[offs - 1])
		mdoc_pmsg(m, ln, offs - 1, MANDOCERR_EOLNSPACE);

	/*
	 * If an initial macro or a list invocation, divert directly
	 * into macro processing.
	 */

	if (NULL == m->last || MDOC_It == tok || MDOC_El == tok) {
		if ( ! mdoc_macro(m, tok, ln, sv, &offs, buf)) 
			goto err;
		return(1);
	}

	n = m->last;
	assert(m->last);

	/*
	 * If the first macro of a `Bl -column', open an `It' block
	 * context around the parsed macro.
	 */

	if (MDOC_Bl == n->tok && MDOC_BODY == n->type &&
			LIST_column == n->norm->Bl.type) {
		m->flags |= MDOC_FREECOL;
		if ( ! mdoc_macro(m, MDOC_It, ln, sv, &sv, buf))
			goto err;
		return(1);
	}

	/*
	 * If we're following a block-level `It' within a `Bl -column'
	 * context (perhaps opened in the above block or in ptext()),
	 * then open an `It' block context around the parsed macro.
	 */

	if (MDOC_It == n->tok && MDOC_BLOCK == n->type &&
			NULL != n->parent &&
			MDOC_Bl == n->parent->tok &&
			LIST_column == n->parent->norm->Bl.type) {
		m->flags |= MDOC_FREECOL;
		if ( ! mdoc_macro(m, MDOC_It, ln, sv, &sv, buf)) 
			goto err;
		return(1);
	}

	/* Normal processing of a macro. */

	if ( ! mdoc_macro(m, tok, ln, sv, &offs, buf)) 
		goto err;

	return(1);

err:	/* Error out. */

	m->flags |= MDOC_HALT;
	return(0);
}

enum mdelim
mdoc_isdelim(const char *p)
{

	if ('\0' == p[0])
		return(DELIM_NONE);

	if ('\0' == p[1])
		switch (p[0]) {
		case('('):
			/* FALLTHROUGH */
		case('['):
			return(DELIM_OPEN);
		case('|'):
			return(DELIM_MIDDLE);
		case('.'):
			/* FALLTHROUGH */
		case(','):
			/* FALLTHROUGH */
		case(';'):
			/* FALLTHROUGH */
		case(':'):
			/* FALLTHROUGH */
		case('?'):
			/* FALLTHROUGH */
		case('!'):
			/* FALLTHROUGH */
		case(')'):
			/* FALLTHROUGH */
		case(']'):
			return(DELIM_CLOSE);
		default:
			return(DELIM_NONE);
		}

	if ('\\' != p[0])
		return(DELIM_NONE);

	if (0 == strcmp(p + 1, "."))
		return(DELIM_CLOSE);
	if (0 == strcmp(p + 1, "*(Ba"))
		return(DELIM_MIDDLE);

	return(DELIM_NONE);
}