Return to eqn.c CVS log

Up to [cvsweb.bsd.lv] / mandoc

Implement in-line equations, much needed by Xenocara manuals.
Put the steering into the roff parser rather than into the mdoc
parser such that it works for all macro languages and on both text
and macro lines.
Line breaks and blank characters generated before and after in-line
equations are not perfect yet, but let's do one thing at a time.

/*	$Id: eqn.c,v 1.54 2014/10/16 01:11:20 schwarze Exp $ */
/*
 * Copyright (c) 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 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 <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "mandoc.h"
#include "mandoc_aux.h"
#include "libmandoc.h"
#include "libroff.h"

#define	EQN_MSG(t, x) \
	mandoc_msg((t), (x)->parse, (x)->eqn.ln, (x)->eqn.pos, NULL)
#define	EQN_NEST_MAX	 128 /* maximum nesting of defines */
#define	STRNEQ(p1, sz1, p2, sz2) \
	((sz1) == (sz2) && 0 == strncmp((p1), (p2), (sz1)))
#define	EQNSTREQ(x, p, sz) \
	STRNEQ((x)->name, (x)->sz, (p), (sz))

enum	eqn_tok {
	EQN_TOK_DYAD = 0,
	EQN_TOK_VEC,
	EQN_TOK_UNDER,
	EQN_TOK_BAR,
	EQN_TOK_TILDE,
	EQN_TOK_HAT,
	EQN_TOK_DOT,
	EQN_TOK_DOTDOT,
	EQN_TOK_FWD,
	EQN_TOK_BACK,
	EQN_TOK_DOWN,
	EQN_TOK_UP,
	EQN_TOK_FAT,
	EQN_TOK_ROMAN,
	EQN_TOK_ITALIC,
	EQN_TOK_BOLD,
	EQN_TOK_SIZE,
	EQN_TOK_SUB,
	EQN_TOK_SUP,
	EQN_TOK_SQRT,
	EQN_TOK_OVER,
	EQN_TOK_FROM,
	EQN_TOK_TO,
	EQN_TOK_BRACE_OPEN,
	EQN_TOK_BRACE_CLOSE,
	EQN_TOK_GSIZE,
	EQN_TOK_GFONT,
	EQN_TOK_MARK,
	EQN_TOK_LINEUP,
	EQN_TOK_LEFT,
	EQN_TOK_RIGHT,
	EQN_TOK_PILE,
	EQN_TOK_LPILE,
	EQN_TOK_RPILE,
	EQN_TOK_CPILE,
	EQN_TOK_MATRIX,
	EQN_TOK_CCOL,
	EQN_TOK_LCOL,
	EQN_TOK_RCOL,
	EQN_TOK_DELIM,
	EQN_TOK_DEFINE,
	EQN_TOK_TDEFINE,
	EQN_TOK_NDEFINE,
	EQN_TOK_UNDEF,
	EQN_TOK_EOF,
	EQN_TOK_ABOVE,
	EQN_TOK__MAX
};

static	const char *eqn_toks[EQN_TOK__MAX] = {
	"dyad", /* EQN_TOK_DYAD */
	"vec", /* EQN_TOK_VEC */
	"under", /* EQN_TOK_UNDER */
	"bar", /* EQN_TOK_BAR */
	"tilde", /* EQN_TOK_TILDE */
	"hat", /* EQN_TOK_HAT */
	"dot", /* EQN_TOK_DOT */
	"dotdot", /* EQN_TOK_DOTDOT */
	"fwd", /* EQN_TOK_FWD * */
	"back", /* EQN_TOK_BACK */
	"down", /* EQN_TOK_DOWN */
	"up", /* EQN_TOK_UP */
	"fat", /* EQN_TOK_FAT */
	"roman", /* EQN_TOK_ROMAN */
	"italic", /* EQN_TOK_ITALIC */
	"bold", /* EQN_TOK_BOLD */
	"size", /* EQN_TOK_SIZE */
	"sub", /* EQN_TOK_SUB */
	"sup", /* EQN_TOK_SUP */
	"sqrt", /* EQN_TOK_SQRT */
	"over", /* EQN_TOK_OVER */
	"from", /* EQN_TOK_FROM */
	"to", /* EQN_TOK_TO */
	"{", /* EQN_TOK_BRACE_OPEN */
	"}", /* EQN_TOK_BRACE_CLOSE */
	"gsize", /* EQN_TOK_GSIZE */
	"gfont", /* EQN_TOK_GFONT */
	"mark", /* EQN_TOK_MARK */
	"lineup", /* EQN_TOK_LINEUP */
	"left", /* EQN_TOK_LEFT */
	"right", /* EQN_TOK_RIGHT */
	"pile", /* EQN_TOK_PILE */
	"lpile", /* EQN_TOK_LPILE */
	"rpile", /* EQN_TOK_RPILE */
	"cpile", /* EQN_TOK_CPILE */
	"matrix", /* EQN_TOK_MATRIX */
	"ccol", /* EQN_TOK_CCOL */
	"lcol", /* EQN_TOK_LCOL */
	"rcol", /* EQN_TOK_RCOL */
	"delim", /* EQN_TOK_DELIM */
	"define", /* EQN_TOK_DEFINE */
	"tdefine", /* EQN_TOK_TDEFINE */
	"ndefine", /* EQN_TOK_NDEFINE */
	"undef", /* EQN_TOK_UNDEF */
	NULL, /* EQN_TOK_EOF */
	"above", /* EQN_TOK_ABOVE */
};

enum	eqn_symt {
	EQNSYM_alpha,
	EQNSYM_beta,
	EQNSYM_chi,
	EQNSYM_delta,
	EQNSYM_epsilon,
	EQNSYM_eta,
	EQNSYM_gamma,
	EQNSYM_iota,
	EQNSYM_kappa,
	EQNSYM_lambda,
	EQNSYM_mu,
	EQNSYM_nu,
	EQNSYM_omega,
	EQNSYM_omicron,
	EQNSYM_phi,
	EQNSYM_pi,
	EQNSYM_ps,
	EQNSYM_rho,
	EQNSYM_sigma,
	EQNSYM_tau,
	EQNSYM_theta,
	EQNSYM_upsilon,
	EQNSYM_xi,
	EQNSYM_zeta,
	EQNSYM_DELTA,
	EQNSYM_GAMMA,
	EQNSYM_LAMBDA,
	EQNSYM_OMEGA,
	EQNSYM_PHI,
	EQNSYM_PI,
	EQNSYM_PSI,
	EQNSYM_SIGMA,
	EQNSYM_THETA,
	EQNSYM_UPSILON,
	EQNSYM_XI,
	EQNSYM_inter,
	EQNSYM_union,
	EQNSYM_prod,
	EQNSYM_int,
	EQNSYM_sum,
	EQNSYM_grad,
	EQNSYM_del,
	EQNSYM_times,
	EQNSYM_cdot,
	EQNSYM_nothing,
	EQNSYM_approx,
	EQNSYM_prime,
	EQNSYM_half,
	EQNSYM_partial,
	EQNSYM_inf,
	EQNSYM_muchgreat,
	EQNSYM_muchless,
	EQNSYM_larrow,
	EQNSYM_rarrow,
	EQNSYM_pm,
	EQNSYM_nequal,
	EQNSYM_equiv,
	EQNSYM_lessequal,
	EQNSYM_moreequal,
	EQNSYM__MAX
};

struct	eqnsym {
	const char	*str;
	const char	*sym;
};

static	const struct eqnsym eqnsyms[EQNSYM__MAX] = {
	{ "alpha", "*a" }, /* EQNSYM_alpha */
	{ "beta", "*b" }, /* EQNSYM_beta */
	{ "chi", "*x" }, /* EQNSYM_chi */
	{ "delta", "*d" }, /* EQNSYM_delta */
	{ "epsilon", "*e" }, /* EQNSYM_epsilon */
	{ "eta", "*y" }, /* EQNSYM_eta */
	{ "gamma", "*g" }, /* EQNSYM_gamma */
	{ "iota", "*i" }, /* EQNSYM_iota */
	{ "kappa", "*k" }, /* EQNSYM_kappa */
	{ "lambda", "*l" }, /* EQNSYM_lambda */
	{ "mu", "*m" }, /* EQNSYM_mu */
	{ "nu", "*n" }, /* EQNSYM_nu */
	{ "omega", "*w" }, /* EQNSYM_omega */
	{ "omicron", "*o" }, /* EQNSYM_omicron */
	{ "phi", "*f" }, /* EQNSYM_phi */
	{ "pi", "*p" }, /* EQNSYM_pi */
	{ "psi", "*q" }, /* EQNSYM_psi */
	{ "rho", "*r" }, /* EQNSYM_rho */
	{ "sigma", "*s" }, /* EQNSYM_sigma */
	{ "tau", "*t" }, /* EQNSYM_tau */
	{ "theta", "*h" }, /* EQNSYM_theta */
	{ "upsilon", "*u" }, /* EQNSYM_upsilon */
	{ "xi", "*c" }, /* EQNSYM_xi */
	{ "zeta", "*z" }, /* EQNSYM_zeta */
	{ "DELTA", "*D" }, /* EQNSYM_DELTA */
	{ "GAMMA", "*G" }, /* EQNSYM_GAMMA */
	{ "LAMBDA", "*L" }, /* EQNSYM_LAMBDA */
	{ "OMEGA", "*W" }, /* EQNSYM_OMEGA */
	{ "PHI", "*F" }, /* EQNSYM_PHI */
	{ "PI", "*P" }, /* EQNSYM_PI */
	{ "PSI", "*Q" }, /* EQNSYM_PSI */
	{ "SIGMA", "*S" }, /* EQNSYM_SIGMA */
	{ "THETA", "*H" }, /* EQNSYM_THETA */
	{ "UPSILON", "*U" }, /* EQNSYM_UPSILON */
	{ "XI", "*C" }, /* EQNSYM_XI */
	{ "inter", "ca" }, /* EQNSYM_inter */
	{ "union", "cu" }, /* EQNSYM_union */
	{ "prod", "product" }, /* EQNSYM_prod */
	{ "int", "integral" }, /* EQNSYM_int */
	{ "sum", "sum" }, /* EQNSYM_sum */
	{ "grad", "gr" }, /* EQNSYM_grad */
	{ "del", "gr" }, /* EQNSYM_del */
	{ "times", "mu" }, /* EQNSYM_times */
	{ "cdot", "pc" }, /* EQNSYM_cdot */
	{ "nothing", "&" }, /* EQNSYM_nothing */
	{ "approx", "~~" }, /* EQNSYM_approx */
	{ "prime", "aq" }, /* EQNSYM_prime */
	{ "half", "12" }, /* EQNSYM_half */
	{ "partial", "pd" }, /* EQNSYM_partial */
	{ "inf", "if" }, /* EQNSYM_inf */
	{ ">>", ">>" }, /* EQNSYM_muchgreat */
	{ "<<", "<<" }, /* EQNSYM_muchless */
	{ "<-", "<-" }, /* EQNSYM_larrow */
	{ "->", "->" }, /* EQNSYM_rarrow */
	{ "+-", "+-" }, /* EQNSYM_pm */
	{ "!=", "!=" }, /* EQNSYM_nequal */
	{ "==", "==" }, /* EQNSYM_equiv */
	{ "<=", "<=" }, /* EQNSYM_lessequal */
	{ ">=", ">=" }, /* EQNSYM_moreequal */
};

enum rofferr
eqn_read(struct eqn_node **epp, int ln,
		const char *p, int pos, int *offs)
{
	size_t		 sz;
	struct eqn_node	*ep;
	enum rofferr	 er;

	ep = *epp;

	/*
	 * If we're the terminating mark, unset our equation status and
	 * validate the full equation.
	 */

	if (0 == strncmp(p, ".EN", 3)) {
		er = eqn_end(epp);
		p += 3;
		while (' ' == *p || '\t' == *p)
			p++;
		if ('\0' == *p)
			return(er);
		mandoc_vmsg(MANDOCERR_ARG_SKIP, ep->parse,
		    ln, pos, "EN %s", p);
		return(er);
	}

	/*
	 * Build up the full string, replacing all newlines with regular
	 * whitespace.
	 */

	sz = strlen(p + pos) + 1;
	ep->data = mandoc_realloc(ep->data, ep->sz + sz + 1);

	/* First invocation: nil terminate the string. */

	if (0 == ep->sz)
		*ep->data = '\0';

	ep->sz += sz;
	strlcat(ep->data, p + pos, ep->sz + 1);
	strlcat(ep->data, " ", ep->sz + 1);
	return(ROFF_IGN);
}

struct eqn_node *
eqn_alloc(const char *name, int pos, int line, struct mparse *parse)
{
	struct eqn_node	*p;
	size_t		 sz;
	const char	*end;

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

	if (name && '\0' != *name) {
		sz = strlen(name);
		assert(sz);
		do {
			sz--;
			end = name + (int)sz;
		} while (' ' == *end || '\t' == *end);
		p->eqn.name = mandoc_strndup(name, sz + 1);
	}

	p->parse = parse;
	p->eqn.ln = line;
	p->eqn.pos = pos;
	p->gsize = EQN_DEFSIZE;

	return(p);
}

/*
 * Find the key "key" of the give size within our eqn-defined values.
 */
static struct eqn_def *
eqn_def_find(struct eqn_node *ep, const char *key, size_t sz)
{
	int		 i;

	for (i = 0; i < (int)ep->defsz; i++)
		if (ep->defs[i].keysz && STRNEQ(ep->defs[i].key,
		    ep->defs[i].keysz, key, sz))
			return(&ep->defs[i]);

	return(NULL);
}

/*
 * Get the next token from the input stream using the given quote
 * character.
 * Optionally make any replacements.
 */
static const char *
eqn_next(struct eqn_node *ep, char quote, size_t *sz, int repl)
{
	char		*start, *next;
	int		 q, diff, lim;
	size_t		 ssz, dummy;
	struct eqn_def	*def;

	if (NULL == sz)
		sz = &dummy;

	lim = 0;
	ep->rew = ep->cur;
again:
	/* Prevent self-definitions. */

	if (lim >= EQN_NEST_MAX) {
		EQN_MSG(MANDOCERR_ROFFLOOP, ep);
		return(NULL);
	}

	ep->cur = ep->rew;
	start = &ep->data[(int)ep->cur];
	q = 0;

	if ('\0' == *start)
		return(NULL);

	if (quote == *start) {
		ep->cur++;
		q = 1;
	}

	start = &ep->data[(int)ep->cur];

	if ( ! q) {
		if ('{' == *start || '}' == *start)
			ssz = 1;
		else
			ssz = strcspn(start + 1, " ^~\"{}\t") + 1;
		next = start + (int)ssz;
		if ('\0' == *next)
			next = NULL;
	} else
		next = strchr(start, quote);

	if (NULL != next) {
		*sz = (size_t)(next - start);
		ep->cur += *sz;
		if (q)
			ep->cur++;
		while (' ' == ep->data[(int)ep->cur] ||
		    '\t' == ep->data[(int)ep->cur] ||
		    '^' == ep->data[(int)ep->cur] ||
		    '~' == ep->data[(int)ep->cur])
			ep->cur++;
	} else {
		if (q)
			EQN_MSG(MANDOCERR_ARG_QUOTE, ep);
		next = strchr(start, '\0');
		*sz = (size_t)(next - start);
		ep->cur += *sz;
	}

	/* Quotes aren't expanded for values. */

	if (q || ! repl)
		return(start);

	if (NULL != (def = eqn_def_find(ep, start, *sz))) {
		diff = def->valsz - *sz;

		if (def->valsz > *sz) {
			ep->sz += diff;
			ep->data = mandoc_realloc(ep->data, ep->sz + 1);
			ep->data[ep->sz] = '\0';
			start = &ep->data[(int)ep->rew];
		}

		diff = def->valsz - *sz;
		memmove(start + *sz + diff, start + *sz,
		    (strlen(start) - *sz) + 1);
		memcpy(start, def->val, def->valsz);
		goto again;
	}

	return(start);
}

/*
 * Get the next delimited token using the default current quote
 * character.
 */
static const char *
eqn_nexttok(struct eqn_node *ep, size_t *sz)
{

	return(eqn_next(ep, '"', sz, 1));
}

/*
 * Get next token without replacement.
 */
static const char *
eqn_nextrawtok(struct eqn_node *ep, size_t *sz)
{

	return(eqn_next(ep, '"', sz, 0));
}

/*
 * Parse a token from the stream of text.
 * A token consists of one of the recognised eqn(7) strings.
 * Strings are separated by delimiting marks.
 * This returns EQN_TOK_EOF when there are no more tokens.
 * If the token is an unrecognised string literal, then it returns
 * EQN_TOK__MAX and sets the "p" pointer to an allocated, nil-terminated
 * string.
 * This must be later freed with free(3).
 */
static enum eqn_tok
eqn_tok_parse(struct eqn_node *ep, char **p)
{
	const char	*start;
	size_t		 i, sz;
	int		 quoted;

	if (NULL != p)
		*p = NULL;

	quoted = ep->data[ep->cur] == '"';

	if (NULL == (start = eqn_nexttok(ep, &sz)))
		return(EQN_TOK_EOF);

	if (quoted) {
		if (p != NULL)
			*p = mandoc_strndup(start, sz);
		return(EQN_TOK__MAX);
	}

	for (i = 0; i < EQN_TOK__MAX; i++) {
		if (NULL == eqn_toks[i])
			continue;
		if (STRNEQ(start, sz, eqn_toks[i], strlen(eqn_toks[i])))
			break;
	}

	if (i == EQN_TOK__MAX && NULL != p)
		*p = mandoc_strndup(start, sz);

	return(i);
}

static void
eqn_box_free(struct eqn_box *bp)
{

	if (bp->first)
		eqn_box_free(bp->first);
	if (bp->next)
		eqn_box_free(bp->next);

	free(bp->text);
	free(bp->left);
	free(bp->right);
	free(bp->top);
	free(bp->bottom);
	free(bp);
}

/*
 * Allocate a box as the last child of the parent node.
 */
static struct eqn_box *
eqn_box_alloc(struct eqn_node *ep, struct eqn_box *parent)
{
	struct eqn_box	*bp;

	bp = mandoc_calloc(1, sizeof(struct eqn_box));
	bp->parent = parent;
	bp->parent->args++;
	bp->expectargs = UINT_MAX;
	bp->size = ep->gsize;

	if (NULL != parent->first) {
		parent->last->next = bp;
		bp->prev = parent->last;
	} else
		parent->first = bp;

	parent->last = bp;
	return(bp);
}

/*
 * Reparent the current last node (of the current parent) under a new
 * EQN_SUBEXPR as the first element.
 * Then return the new parent.
 * The new EQN_SUBEXPR will have a two-child limit.
 */
static struct eqn_box *
eqn_box_makebinary(struct eqn_node *ep,
	enum eqn_post pos, struct eqn_box *parent)
{
	struct eqn_box	*b, *newb;

	assert(NULL != parent->last);
	b = parent->last;
	if (parent->last == parent->first)
		parent->first = NULL;
	parent->args--;
	parent->last = b->prev;
	b->prev = NULL;
	newb = eqn_box_alloc(ep, parent);
	newb->pos = pos;
	newb->type = EQN_SUBEXPR;
	newb->expectargs = 2;
	newb->args = 1;
	newb->first = newb->last = b;
	newb->first->next = NULL;
	b->parent = newb;
	return(newb);
}

/*
 * Parse the "delim" control statement.
 */
static void
eqn_delim(struct eqn_node *ep)
{
	const char	*start;
	size_t		 sz;

	if ((start = eqn_nextrawtok(ep, &sz)) == NULL)
		mandoc_msg(MANDOCERR_REQ_EMPTY, ep->parse,
		    ep->eqn.ln, ep->eqn.pos, "delim");
	else if (strncmp(start, "off", 3) == 0)
		ep->delim = 0;
	else if (strncmp(start, "on", 2) == 0) {
		if (ep->odelim && ep->cdelim)
			ep->delim = 1;
	} else if (start[1] != '\0') {
		ep->odelim = start[0];
		ep->cdelim = start[1];
		ep->delim = 1;
	}
}

/*
 * Undefine a previously-defined string.
 */
static int
eqn_undef(struct eqn_node *ep)
{
	const char	*start;
	struct eqn_def	*def;
	size_t		 sz;

	if (NULL == (start = eqn_nextrawtok(ep, &sz))) {
		EQN_MSG(MANDOCERR_EQNEOF, ep);
		return(0);
	} else if (NULL != (def = eqn_def_find(ep, start, sz)))
		def->keysz = 0;

	return(1);
}

static int
eqn_def(struct eqn_node *ep)
{
	const char	*start;
	size_t		 sz;
	struct eqn_def	*def;
	int		 i;

	if (NULL == (start = eqn_nextrawtok(ep, &sz))) {
		EQN_MSG(MANDOCERR_EQNEOF, ep);
		return(0);
	}

	/*
	 * Search for a key that already exists.
	 * Create a new key if none is found.
	 */
	if (NULL == (def = eqn_def_find(ep, start, sz))) {
		/* Find holes in string array. */
		for (i = 0; i < (int)ep->defsz; i++)
			if (0 == ep->defs[i].keysz)
				break;

		if (i == (int)ep->defsz) {
			ep->defsz++;
			ep->defs = mandoc_reallocarray(ep->defs,
			    ep->defsz, sizeof(struct eqn_def));
			ep->defs[i].key = ep->defs[i].val = NULL;
		}

		ep->defs[i].keysz = sz;
		ep->defs[i].key = mandoc_realloc(
		    ep->defs[i].key, sz + 1);

		memcpy(ep->defs[i].key, start, sz);
		ep->defs[i].key[(int)sz] = '\0';
		def = &ep->defs[i];
	}

	start = eqn_next(ep, ep->data[(int)ep->cur], &sz, 0);

	if (NULL == start) {
		EQN_MSG(MANDOCERR_EQNEOF, ep);
		return(-1);
	}

	def->valsz = sz;
	def->val = mandoc_realloc(def->val, sz + 1);
	memcpy(def->val, start, sz);
	def->val[(int)sz] = '\0';
	return(1);
}

/*
 * Recursively parse an eqn(7) expression.
 */
static int
eqn_parse(struct eqn_node *ep, struct eqn_box *parent)
{
	char		*p;
	enum eqn_tok	 tok, subtok;
	enum eqn_post	 pos;
	struct eqn_box	*cur;
	int		 rc, size;
	size_t		 i, sz;
	char		 sym[64];
	const char	*start;

	assert(NULL != parent);

next_tok:
	tok = eqn_tok_parse(ep, &p);

this_tok:
	switch (tok) {
	case (EQN_TOK_UNDEF):
		if ((rc = eqn_undef(ep)) <= 0)
			return(rc);
		break;
	case (EQN_TOK_NDEFINE):
	case (EQN_TOK_DEFINE):
		if ((rc = eqn_def(ep)) <= 0)
			return(rc);
		break;
	case (EQN_TOK_TDEFINE):
		if (NULL == eqn_nextrawtok(ep, NULL))
			EQN_MSG(MANDOCERR_EQNEOF, ep);
		else if (NULL == eqn_next(ep,
				ep->data[(int)ep->cur], NULL, 0))
			EQN_MSG(MANDOCERR_EQNEOF, ep);
		break;
	case (EQN_TOK_DELIM):
		eqn_delim(ep);
		break;
	case (EQN_TOK_GFONT):
		if (eqn_nextrawtok(ep, NULL) == NULL)
			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
		break;
	case (EQN_TOK_MARK):
	case (EQN_TOK_LINEUP):
		/* Ignore these. */
		break;
	case (EQN_TOK_DYAD):
	case (EQN_TOK_VEC):
	case (EQN_TOK_UNDER):
	case (EQN_TOK_BAR):
	case (EQN_TOK_TILDE):
	case (EQN_TOK_HAT):
	case (EQN_TOK_DOT):
	case (EQN_TOK_DOTDOT):
		if (parent->last == NULL) {
			mandoc_msg(MANDOCERR_EQN_NOBOX, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			cur = eqn_box_alloc(ep, parent);
			cur->type = EQN_TEXT;
			cur->text = mandoc_strdup("");
		}
		parent = eqn_box_makebinary(ep, EQNPOS_NONE, parent);
		parent->type = EQN_LISTONE;
		parent->expectargs = 1;
		switch (tok) {
		case (EQN_TOK_DOTDOT):
			strlcpy(sym, "\\[ad]", sizeof(sym));
			break;
		case (EQN_TOK_VEC):
			strlcpy(sym, "\\[->]", sizeof(sym));
			break;
		case (EQN_TOK_DYAD):
			strlcpy(sym, "\\[<>]", sizeof(sym));
			break;
		case (EQN_TOK_TILDE):
			strlcpy(sym, "\\[a~]", sizeof(sym));
			break;
		case (EQN_TOK_UNDER):
			strlcpy(sym, "\\[ul]", sizeof(sym));
			break;
		case (EQN_TOK_BAR):
			strlcpy(sym, "\\[rl]", sizeof(sym));
			break;
		case (EQN_TOK_DOT):
			strlcpy(sym, "\\[a.]", sizeof(sym));
			break;
		case (EQN_TOK_HAT):
			strlcpy(sym, "\\[ha]", sizeof(sym));
			break;
		default:
			abort();
		}

		switch (tok) {
		case (EQN_TOK_DOTDOT):
		case (EQN_TOK_VEC):
		case (EQN_TOK_DYAD):
		case (EQN_TOK_TILDE):
		case (EQN_TOK_BAR):
		case (EQN_TOK_DOT):
		case (EQN_TOK_HAT):
			parent->top = mandoc_strdup(sym);
			break;
		case (EQN_TOK_UNDER):
			parent->bottom = mandoc_strdup(sym);
			break;
		default:
			abort();
		}
		parent = parent->parent;
		break;
	case (EQN_TOK_FWD):
	case (EQN_TOK_BACK):
	case (EQN_TOK_DOWN):
	case (EQN_TOK_UP):
		subtok = eqn_tok_parse(ep, NULL);
		if (subtok != EQN_TOK__MAX) {
			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			tok = subtok;
			goto this_tok;
		}
		break;
	case (EQN_TOK_FAT):
	case (EQN_TOK_ROMAN):
	case (EQN_TOK_ITALIC):
	case (EQN_TOK_BOLD):
		while (parent->args == parent->expectargs)
			parent = parent->parent;
		/*
		 * These values apply to the next word or sequence of
		 * words; thus, we mark that we'll have a child with
		 * exactly one of those.
		 */
		parent = eqn_box_alloc(ep, parent);
		parent->type = EQN_LISTONE;
		parent->expectargs = 1;
		switch (tok) {
		case (EQN_TOK_FAT):
			parent->font = EQNFONT_FAT;
			break;
		case (EQN_TOK_ROMAN):
			parent->font = EQNFONT_ROMAN;
			break;
		case (EQN_TOK_ITALIC):
			parent->font = EQNFONT_ITALIC;
			break;
		case (EQN_TOK_BOLD):
			parent->font = EQNFONT_BOLD;
			break;
		default:
			abort();
		}
		break;
	case (EQN_TOK_SIZE):
	case (EQN_TOK_GSIZE):
		/* Accept two values: integral size and a single. */
		if (NULL == (start = eqn_nexttok(ep, &sz))) {
			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			break;
		}
		size = mandoc_strntoi(start, sz, 10);
		if (-1 == size) {
			mandoc_msg(MANDOCERR_IT_NONUM, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			break;
		}
		if (EQN_TOK_GSIZE == tok) {
			ep->gsize = size;
			break;
		}
		parent = eqn_box_alloc(ep, parent);
		parent->type = EQN_LISTONE;
		parent->expectargs = 1;
		parent->size = size;
		break;
	case (EQN_TOK_FROM):
	case (EQN_TOK_TO):
	case (EQN_TOK_SUB):
	case (EQN_TOK_SUP):
		/*
		 * We have a left-right-associative expression.
		 * Repivot under a positional node, open a child scope
		 * and keep on reading.
		 */
		if (parent->last == NULL) {
			mandoc_msg(MANDOCERR_EQN_NOBOX, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			cur = eqn_box_alloc(ep, parent);
			cur->type = EQN_TEXT;
			cur->text = mandoc_strdup("");
		}
		/* Handle the "subsup" and "fromto" positions. */
		if (EQN_TOK_SUP == tok && parent->pos == EQNPOS_SUB) {
			parent->expectargs = 3;
			parent->pos = EQNPOS_SUBSUP;
			break;
		}
		if (EQN_TOK_TO == tok && parent->pos == EQNPOS_FROM) {
			parent->expectargs = 3;
			parent->pos = EQNPOS_FROMTO;
			break;
		}
		switch (tok) {
		case (EQN_TOK_FROM):
			pos = EQNPOS_FROM;
			break;
		case (EQN_TOK_TO):
			pos = EQNPOS_TO;
			break;
		case (EQN_TOK_SUP):
			pos = EQNPOS_SUP;
			break;
		case (EQN_TOK_SUB):
			pos = EQNPOS_SUB;
			break;
		default:
			abort();
		}
		parent = eqn_box_makebinary(ep, pos, parent);
		break;
	case (EQN_TOK_SQRT):
		while (parent->args == parent->expectargs)
			parent = parent->parent;
		/*
		 * Accept a left-right-associative set of arguments just
		 * like sub and sup and friends but without rebalancing
		 * under a pivot.
		 */
		parent = eqn_box_alloc(ep, parent);
		parent->type = EQN_SUBEXPR;
		parent->pos = EQNPOS_SQRT;
		parent->expectargs = 1;
		break;
	case (EQN_TOK_OVER):
		/*
		 * We have a right-left-associative fraction.
		 * Close out anything that's currently open, then
		 * rebalance and continue reading.
		 */
		if (parent->last == NULL) {
			mandoc_msg(MANDOCERR_EQN_NOBOX, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			cur = eqn_box_alloc(ep, parent);
			cur->type = EQN_TEXT;
			cur->text = mandoc_strdup("");
		}
		while (EQN_SUBEXPR == parent->type)
			parent = parent->parent;
		parent = eqn_box_makebinary(ep, EQNPOS_OVER, parent);
		break;
	case (EQN_TOK_RIGHT):
	case (EQN_TOK_BRACE_CLOSE):
		/*
		 * Close out the existing brace.
		 * FIXME: this is a shitty sentinel: we should really
		 * have a native EQN_BRACE type or whatnot.
		 */
		for (cur = parent; cur != NULL; cur = cur->parent)
			if (cur->type == EQN_LIST &&
			    (tok == EQN_TOK_BRACE_CLOSE ||
			     cur->left != NULL))
				break;
		if (cur == NULL) {
			mandoc_msg(MANDOCERR_BLK_NOTOPEN, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			break;
		}
		parent = cur;
		if (EQN_TOK_RIGHT == tok) {
			if (NULL == (start = eqn_nexttok(ep, &sz))) {
				mandoc_msg(MANDOCERR_REQ_EMPTY,
				    ep->parse, ep->eqn.ln,
				    ep->eqn.pos, eqn_toks[tok]);
				break;
			}
			/* Handling depends on right/left. */
			if (STRNEQ(start, sz, "ceiling", 7)) {
				strlcpy(sym, "\\[rc]", sizeof(sym));
				parent->right = mandoc_strdup(sym);
			} else if (STRNEQ(start, sz, "floor", 5)) {
				strlcpy(sym, "\\[rf]", sizeof(sym));
				parent->right = mandoc_strdup(sym);
			} else
				parent->right = mandoc_strndup(start, sz);
		}
		parent = parent->parent;
		if (EQN_TOK_BRACE_CLOSE == tok && parent &&
		    (parent->type == EQN_PILE ||
		     parent->type == EQN_MATRIX))
			parent = parent->parent;
		/* Close out any "singleton" lists. */
		while (parent->type == EQN_LISTONE &&
		    parent->args == parent->expectargs)
			parent = parent->parent;
		break;
	case (EQN_TOK_BRACE_OPEN):
	case (EQN_TOK_LEFT):
		/*
		 * If we already have something in the stack and we're
		 * in an expression, then rewind til we're not any more
		 * (just like with the text node).
		 */
		while (parent->args == parent->expectargs)
			parent = parent->parent;
		if (EQN_TOK_LEFT == tok &&
		    (start = eqn_nexttok(ep, &sz)) == NULL) {
			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			break;
		}
		parent = eqn_box_alloc(ep, parent);
		parent->type = EQN_LIST;
		if (EQN_TOK_LEFT == tok) {
			if (STRNEQ(start, sz, "ceiling", 7)) {
				strlcpy(sym, "\\[lc]", sizeof(sym));
				parent->left = mandoc_strdup(sym);
			} else if (STRNEQ(start, sz, "floor", 5)) {
				strlcpy(sym, "\\[lf]", sizeof(sym));
				parent->left = mandoc_strdup(sym);
			} else
				parent->left = mandoc_strndup(start, sz);
		}
		break;
	case (EQN_TOK_PILE):
	case (EQN_TOK_LPILE):
	case (EQN_TOK_RPILE):
	case (EQN_TOK_CPILE):
	case (EQN_TOK_CCOL):
	case (EQN_TOK_LCOL):
	case (EQN_TOK_RCOL):
		while (parent->args == parent->expectargs)
			parent = parent->parent;
		parent = eqn_box_alloc(ep, parent);
		parent->type = EQN_PILE;
		parent->expectargs = 1;
		break;
	case (EQN_TOK_ABOVE):
		for (cur = parent; cur != NULL; cur = cur->parent)
			if (cur->type == EQN_PILE)
				break;
		if (cur == NULL) {
			mandoc_msg(MANDOCERR_IT_STRAY, ep->parse,
			    ep->eqn.ln, ep->eqn.pos, eqn_toks[tok]);
			break;
		}
		parent = eqn_box_alloc(ep, cur);
		parent->type = EQN_LIST;
		break;
	case (EQN_TOK_MATRIX):
		while (parent->args == parent->expectargs)
			parent = parent->parent;
		parent = eqn_box_alloc(ep, parent);
		parent->type = EQN_MATRIX;
		parent->expectargs = 1;
		break;
	case (EQN_TOK_EOF):
		/*
		 * End of file!
		 * TODO: make sure we're not in an open subexpression.
		 */
		return(0);
	default:
		assert(tok == EQN_TOK__MAX);
		assert(NULL != p);
		/*
		 * If we already have something in the stack and we're
		 * in an expression, then rewind til we're not any more.
		 */
		while (parent->args == parent->expectargs)
			parent = parent->parent;
		cur = eqn_box_alloc(ep, parent);
		cur->type = EQN_TEXT;
		for (i = 0; i < EQNSYM__MAX; i++)
			if (0 == strcmp(eqnsyms[i].str, p)) {
				(void)snprintf(sym, sizeof(sym),
					"\\[%s]", eqnsyms[i].sym);
				cur->text = mandoc_strdup(sym);
				free(p);
				break;
			}

		if (i == EQNSYM__MAX)
			cur->text = p;
		/*
		 * Post-process list status.
		 */
		while (parent->type == EQN_LISTONE &&
		    parent->args == parent->expectargs)
			parent = parent->parent;
		break;
	}
	goto next_tok;
}

enum rofferr
eqn_end(struct eqn_node **epp)
{
	struct eqn_node	*ep;

	ep = *epp;
	*epp = NULL;

	ep->eqn.root = mandoc_calloc(1, sizeof(struct eqn_box));
	ep->eqn.root->expectargs = UINT_MAX;
	return(0 == eqn_parse(ep, ep->eqn.root) ? ROFF_EQN : ROFF_IGN);
}

void
eqn_free(struct eqn_node *p)
{
	int		 i;

	eqn_box_free(p->eqn.root);

	for (i = 0; i < (int)p->defsz; i++) {
		free(p->defs[i].key);
		free(p->defs[i].val);
	}

	free(p->eqn.name);
	free(p->data);
	free(p->defs);
	free(p);
}