IABSD.fr/src/usr.bin/mandoc/eqn.c

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• Author : schwarze
  Date : 2018-12-14 06:33:03
  Hash : 91305757
  Message : Cleanup, no functional change: Now that message handling is properly encapsulated, remove struct mparse pointers from four structs (roff, roff_man, tbl_node, eqn_node) and from the argument lists of five functions (roff_alloc, roff_man_alloc, mandoc_getarg, tbl_alloc, eqn_alloc). Except for being passed to the main program as an opaque object, it now only occurs in read.c, as it should, and not across 15 files like in the past.

• usr.bin/mandoc/eqn.c

• /*	$OpenBSD: eqn.c,v 1.46 2018/12/14 06:33:03 schwarze Exp $ */
  /*
   * Copyright (c) 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
   * Copyright (c) 2014, 2015, 2017, 2018 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 <sys/types.h>
  
  #include <assert.h>
  #include <ctype.h>
  #include <limits.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <time.h>
  
  #include "mandoc_aux.h"
  #include "mandoc.h"
  #include "roff.h"
  #include "eqn.h"
  #include "libmandoc.h"
  #include "eqn_parse.h"
  
  #define	EQN_NEST_MAX	 128 /* maximum nesting of defines */
  #define	STRNEQ(p1, sz1, p2, sz2) \
  	((sz1) == (sz2) && 0 == strncmp((p1), (p2), (sz1)))
  
  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_ABOVE,
  	EQN_TOK__MAX,
  	EQN_TOK_FUNC,
  	EQN_TOK_QUOTED,
  	EQN_TOK_SYM,
  	EQN_TOK_EOF
  };
  
  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 */
  	"above", /* EQN_TOK_ABOVE */
  };
  
  static	const char *const eqn_func[] = {
  	"acos",	"acsc",	"and",	"arc",	"asec",	"asin", "atan",
  	"cos",	"cosh", "coth",	"csc",	"det",	"exp",	"for",
  	"if",	"lim",	"ln",	"log",	"max",	"min",
  	"sec",	"sin",	"sinh",	"tan",	"tanh",	"Im",	"Re",
  };
  
  enum	eqn_symt {
  	EQNSYM_alpha = 0,
  	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_minus,
  	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", "fm" }, /* 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 */
  	{ "-", "mi" }, /* EQNSYM_minus */
  };
  
  enum	parse_mode {
  	MODE_QUOTED,
  	MODE_NOSUB,
  	MODE_SUB,
  	MODE_TOK
  };
  
  struct	eqn_def {
  	char		 *key;
  	size_t		  keysz;
  	char		 *val;
  	size_t		  valsz;
  };
  
  static	struct eqn_box	*eqn_box_alloc(struct eqn_node *, struct eqn_box *);
  static	struct eqn_box	*eqn_box_makebinary(struct eqn_node *,
  				struct eqn_box *);
  static	void		 eqn_def(struct eqn_node *);
  static	struct eqn_def	*eqn_def_find(struct eqn_node *);
  static	void		 eqn_delim(struct eqn_node *);
  static	enum eqn_tok	 eqn_next(struct eqn_node *, enum parse_mode);
  static	void		 eqn_undef(struct eqn_node *);
  
  
  struct eqn_node *
  eqn_alloc(void)
  {
  	struct eqn_node *ep;
  
  	ep = mandoc_calloc(1, sizeof(*ep));
  	ep->gsize = EQN_DEFSIZE;
  	return ep;
  }
  
  void
  eqn_reset(struct eqn_node *ep)
  {
  	free(ep->data);
  	ep->data = ep->start = ep->end = NULL;
  	ep->sz = ep->toksz = 0;
  }
  
  void
  eqn_read(struct eqn_node *ep, const char *p)
  {
  	char		*cp;
  
  	if (ep->data == NULL) {
  		ep->sz = strlen(p);
  		ep->data = mandoc_strdup(p);
  	} else {
  		ep->sz = mandoc_asprintf(&cp, "%s %s", ep->data, p);
  		free(ep->data);
  		ep->data = cp;
  	}
  	ep->sz += 1;
  }
  
  /*
   * Find the key "key" of the give size within our eqn-defined values.
   */
  static struct eqn_def *
  eqn_def_find(struct eqn_node *ep)
  {
  	int		 i;
  
  	for (i = 0; i < (int)ep->defsz; i++)
  		if (ep->defs[i].keysz && STRNEQ(ep->defs[i].key,
  		    ep->defs[i].keysz, ep->start, ep->toksz))
  			return &ep->defs[i];
  
  	return NULL;
  }
  
  /*
   * Parse a token from the input text.  The modes are:
   * MODE_QUOTED: Use *ep->start as the delimiter; the token ends
   *   before its next occurence.  Do not interpret the token in any
   *   way and return EQN_TOK_QUOTED.  All other modes behave like
   *   MODE_QUOTED when *ep->start is '"'.
   * MODE_NOSUB: If *ep->start is a curly brace, the token ends after it;
   *   otherwise, it ends before the next whitespace or brace.
   *   Do not interpret the token and return EQN_TOK__MAX.
   * MODE_SUB: Like MODE_NOSUB, but try to interpret the token as an
   *   alias created with define.  If it is an alias, replace it with
   *   its string value and reparse.
   * MODE_TOK: Like MODE_SUB, but also check the token against the list
   *   of tokens, and if there is a match, return that token.  Otherwise,
   *   if the token matches a symbol, return EQN_TOK_SYM; if it matches
   *   a function name, EQN_TOK_FUNC, or else EQN_TOK__MAX.  Except for
   *   a token match, *ep->start is set to an allocated string that the
   *   caller is expected to free.
   * All modes skip whitespace following the end of the token.
   */
  static enum eqn_tok
  eqn_next(struct eqn_node *ep, enum parse_mode mode)
  {
  	static int	 last_len, lim;
  
  	struct eqn_def	*def;
  	size_t		 start;
  	int		 diff, i, quoted;
  	enum eqn_tok	 tok;
  
  	/*
  	 * Reset the recursion counter after advancing
  	 * beyond the end of the previous substitution.
  	 */
  	if (ep->end - ep->data >= last_len)
  		lim = 0;
  
  	ep->start = ep->end;
  	quoted = mode == MODE_QUOTED;
  	for (;;) {
  		switch (*ep->start) {
  		case '\0':
  			ep->toksz = 0;
  			return EQN_TOK_EOF;
  		case '"':
  			quoted = 1;
  			break;
  		default:
  			break;
  		}
  		if (quoted) {
  			ep->end = strchr(ep->start + 1, *ep->start);
  			ep->start++;  /* Skip opening quote. */
  			if (ep->end == NULL) {
  				mandoc_msg(MANDOCERR_ARG_QUOTE,
  				    ep->node->line, ep->node->pos, NULL);
  				ep->end = strchr(ep->start, '\0');
  			}
  		} else {
  			ep->end = ep->start + 1;
  			if (*ep->start != '{' && *ep->start != '}')
  				ep->end += strcspn(ep->end, " ^~\"{}\t");
  		}
  		ep->toksz = ep->end - ep->start;
  		if (quoted && *ep->end != '\0')
  			ep->end++;  /* Skip closing quote. */
  		while (*ep->end != '\0' && strchr(" \t^~", *ep->end) != NULL)
  			ep->end++;
  		if (quoted)  /* Cannot return, may have to strndup. */
  			break;
  		if (mode == MODE_NOSUB)
  			return EQN_TOK__MAX;
  		if ((def = eqn_def_find(ep)) == NULL)
  			break;
  		if (++lim > EQN_NEST_MAX) {
  			mandoc_msg(MANDOCERR_ROFFLOOP,
  			    ep->node->line, ep->node->pos, NULL);
  			return EQN_TOK_EOF;
  		}
  
  		/* Replace a defined name with its string value. */
  		if ((diff = def->valsz - ep->toksz) > 0) {
  			start = ep->start - ep->data;
  			ep->sz += diff;
  			ep->data = mandoc_realloc(ep->data, ep->sz + 1);
  			ep->start = ep->data + start;
  		}
  		if (diff)
  			memmove(ep->start + def->valsz, ep->start + ep->toksz,
  			    strlen(ep->start + ep->toksz) + 1);
  		memcpy(ep->start, def->val, def->valsz);
  		last_len = ep->start - ep->data + def->valsz;
  	}
  	if (mode != MODE_TOK)
  		return quoted ? EQN_TOK_QUOTED : EQN_TOK__MAX;
  	if (quoted) {
  		ep->start = mandoc_strndup(ep->start, ep->toksz);
  		return EQN_TOK_QUOTED;
  	}
  	for (tok = 0; tok < EQN_TOK__MAX; tok++)
  		if (STRNEQ(ep->start, ep->toksz,
  		    eqn_toks[tok], strlen(eqn_toks[tok])))
  			return tok;
  
  	for (i = 0; i < EQNSYM__MAX; i++) {
  		if (STRNEQ(ep->start, ep->toksz,
  		    eqnsyms[i].str, strlen(eqnsyms[i].str))) {
  			mandoc_asprintf(&ep->start,
  			    "\\[%s]", eqnsyms[i].sym);
  			return EQN_TOK_SYM;
  		}
  	}
  	ep->start = mandoc_strndup(ep->start, ep->toksz);
  	for (i = 0; i < (int)(sizeof(eqn_func)/sizeof(*eqn_func)); i++)
  		if (STRNEQ(ep->start, ep->toksz,
  		    eqn_func[i], strlen(eqn_func[i])))
  			return EQN_TOK_FUNC;
  	return EQN_TOK__MAX;
  }
  
  void
  eqn_box_free(struct eqn_box *bp)
  {
  	if (bp == NULL)
  		return;
  
  	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);
  }
  
  struct eqn_box *
  eqn_box_new(void)
  {
  	struct eqn_box	*bp;
  
  	bp = mandoc_calloc(1, sizeof(*bp));
  	bp->expectargs = UINT_MAX;
  	return 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 = eqn_box_new();
  	bp->parent = parent;
  	bp->parent->args++;
  	bp->font = bp->parent->font;
  	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, 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->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)
  {
  	if (ep->end[0] == '\0' || ep->end[1] == '\0') {
  		mandoc_msg(MANDOCERR_REQ_EMPTY,
  		    ep->node->line, ep->node->pos, "delim");
  		if (ep->end[0] != '\0')
  			ep->end++;
  	} else if (strncmp(ep->end, "off", 3) == 0) {
  		ep->delim = 0;
  		ep->end += 3;
  	} else if (strncmp(ep->end, "on", 2) == 0) {
  		if (ep->odelim && ep->cdelim)
  			ep->delim = 1;
  		ep->end += 2;
  	} else {
  		ep->odelim = *ep->end++;
  		ep->cdelim = *ep->end++;
  		ep->delim = 1;
  	}
  }
  
  /*
   * Undefine a previously-defined string.
   */
  static void
  eqn_undef(struct eqn_node *ep)
  {
  	struct eqn_def	*def;
  
  	if (eqn_next(ep, MODE_NOSUB) == EQN_TOK_EOF) {
  		mandoc_msg(MANDOCERR_REQ_EMPTY,
  		    ep->node->line, ep->node->pos, "undef");
  		return;
  	}
  	if ((def = eqn_def_find(ep)) == NULL)
  		return;
  	free(def->key);
  	free(def->val);
  	def->key = def->val = NULL;
  	def->keysz = def->valsz = 0;
  }
  
  static void
  eqn_def(struct eqn_node *ep)
  {
  	struct eqn_def	*def;
  	int		 i;
  
  	if (eqn_next(ep, MODE_NOSUB) == EQN_TOK_EOF) {
  		mandoc_msg(MANDOCERR_REQ_EMPTY,
  		    ep->node->line, ep->node->pos, "define");
  		return;
  	}
  
  	/*
  	 * Search for a key that already exists.
  	 * Create a new key if none is found.
  	 */
  	if ((def = eqn_def_find(ep)) == NULL) {
  		/* 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;
  		}
  
  		def = ep->defs + i;
  		free(def->key);
  		def->key = mandoc_strndup(ep->start, ep->toksz);
  		def->keysz = ep->toksz;
  	}
  
  	if (eqn_next(ep, MODE_QUOTED) == EQN_TOK_EOF) {
  		mandoc_msg(MANDOCERR_REQ_EMPTY,
  		    ep->node->line, ep->node->pos, "define %s", def->key);
  		free(def->key);
  		free(def->val);
  		def->key = def->val = NULL;
  		def->keysz = def->valsz = 0;
  		return;
  	}
  	free(def->val);
  	def->val = mandoc_strndup(ep->start, ep->toksz);
  	def->valsz = ep->toksz;
  }
  
  void
  eqn_parse(struct eqn_node *ep)
  {
  	struct eqn_box	*cur, *nbox, *parent, *split;
  	const char	*cp, *cpn;
  	char		*p;
  	enum eqn_tok	 tok;
  	enum { CCL_LET, CCL_DIG, CCL_PUN } ccl, ccln;
  	int		 size;
  
  	parent = ep->node->eqn;
  	assert(parent != NULL);
  
  	/*
  	 * Empty equation.
  	 * Do not add it to the high-level syntax tree.
  	 */
  
  	if (ep->data == NULL)
  		return;
  
  	ep->start = ep->end = ep->data + strspn(ep->data, " ^~");
  
  next_tok:
  	tok = eqn_next(ep, MODE_TOK);
  	switch (tok) {
  	case EQN_TOK_UNDEF:
  		eqn_undef(ep);
  		break;
  	case EQN_TOK_NDEFINE:
  	case EQN_TOK_DEFINE:
  		eqn_def(ep);
  		break;
  	case EQN_TOK_TDEFINE:
  		if (eqn_next(ep, MODE_NOSUB) == EQN_TOK_EOF ||
  		    eqn_next(ep, MODE_QUOTED) == EQN_TOK_EOF)
  			mandoc_msg(MANDOCERR_REQ_EMPTY,
  			    ep->node->line, ep->node->pos, "tdefine");
  		break;
  	case EQN_TOK_DELIM:
  		eqn_delim(ep);
  		break;
  	case EQN_TOK_GFONT:
  		if (eqn_next(ep, MODE_SUB) == EQN_TOK_EOF)
  			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->node->line,
  			    ep->node->pos, "%s", 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->node->line,
  			    ep->node->pos, "%s", eqn_toks[tok]);
  			cur = eqn_box_alloc(ep, parent);
  			cur->type = EQN_TEXT;
  			cur->text = mandoc_strdup("");
  		}
  		parent = eqn_box_makebinary(ep, parent);
  		parent->type = EQN_LIST;
  		parent->expectargs = 1;
  		parent->font = EQNFONT_ROMAN;
  		switch (tok) {
  		case EQN_TOK_DOTDOT:
  			parent->top = mandoc_strdup("\\[ad]");
  			break;
  		case EQN_TOK_VEC:
  			parent->top = mandoc_strdup("\\[->]");
  			break;
  		case EQN_TOK_DYAD:
  			parent->top = mandoc_strdup("\\[<>]");
  			break;
  		case EQN_TOK_TILDE:
  			parent->top = mandoc_strdup("\\[a~]");
  			break;
  		case EQN_TOK_UNDER:
  			parent->bottom = mandoc_strdup("\\[ul]");
  			break;
  		case EQN_TOK_BAR:
  			parent->top = mandoc_strdup("\\[rn]");
  			break;
  		case EQN_TOK_DOT:
  			parent->top = mandoc_strdup("\\[a.]");
  			break;
  		case EQN_TOK_HAT:
  			parent->top = mandoc_strdup("\\[ha]");
  			break;
  		default:
  			abort();
  		}
  		parent = parent->parent;
  		break;
  	case EQN_TOK_FWD:
  	case EQN_TOK_BACK:
  	case EQN_TOK_DOWN:
  	case EQN_TOK_UP:
  		if (eqn_next(ep, MODE_SUB) == EQN_TOK_EOF)
  			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->node->line,
  			    ep->node->pos, "%s", eqn_toks[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_LIST;
  		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 (eqn_next(ep, MODE_SUB) == EQN_TOK_EOF) {
  			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->node->line,
  			    ep->node->pos, "%s", eqn_toks[tok]);
  			break;
  		}
  		size = mandoc_strntoi(ep->start, ep->toksz, 10);
  		if (-1 == size) {
  			mandoc_msg(MANDOCERR_IT_NONUM, ep->node->line,
  			    ep->node->pos, "%s", eqn_toks[tok]);
  			break;
  		}
  		if (EQN_TOK_GSIZE == tok) {
  			ep->gsize = size;
  			break;
  		}
  		while (parent->args == parent->expectargs)
  			parent = parent->parent;
  		parent = eqn_box_alloc(ep, parent);
  		parent->type = EQN_LIST;
  		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->node->line,
  			    ep->node->pos, "%s", eqn_toks[tok]);
  			cur = eqn_box_alloc(ep, parent);
  			cur->type = EQN_TEXT;
  			cur->text = mandoc_strdup("");
  		}
  		while (parent->expectargs == 1 && parent->args == 1)
  			parent = parent->parent;
  		if (tok == EQN_TOK_FROM || tok == EQN_TOK_TO)  {
  			for (cur = parent; cur != NULL; cur = cur->parent)
  				if (cur->pos == EQNPOS_SUB ||
  				    cur->pos == EQNPOS_SUP ||
  				    cur->pos == EQNPOS_SUBSUP ||
  				    cur->pos == EQNPOS_SQRT ||
  				    cur->pos == EQNPOS_OVER)
  					break;
  			if (cur != NULL)
  				parent = cur->parent;
  		}
  		if (tok == EQN_TOK_SUP && parent->pos == EQNPOS_SUB) {
  			parent->expectargs = 3;
  			parent->pos = EQNPOS_SUBSUP;
  			break;
  		}
  		if (tok == EQN_TOK_TO && parent->pos == EQNPOS_FROM) {
  			parent->expectargs = 3;
  			parent->pos = EQNPOS_FROMTO;
  			break;
  		}
  		parent = eqn_box_makebinary(ep, parent);
  		switch (tok) {
  		case EQN_TOK_FROM:
  			parent->pos = EQNPOS_FROM;
  			break;
  		case EQN_TOK_TO:
  			parent->pos = EQNPOS_TO;
  			break;
  		case EQN_TOK_SUP:
  			parent->pos = EQNPOS_SUP;
  			break;
  		case EQN_TOK_SUB:
  			parent->pos = EQNPOS_SUB;
  			break;
  		default:
  			abort();
  		}
  		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->node->line,
  			    ep->node->pos, "%s", eqn_toks[tok]);
  			cur = eqn_box_alloc(ep, parent);
  			cur->type = EQN_TEXT;
  			cur->text = mandoc_strdup("");
  		}
  		while (parent->args == parent->expectargs)
  			parent = parent->parent;
  		while (EQN_SUBEXPR == parent->type)
  			parent = parent->parent;
  		parent = eqn_box_makebinary(ep, parent);
  		parent->pos = EQNPOS_OVER;
  		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 &&
  			    cur->expectargs > 1 &&
  			    (tok == EQN_TOK_BRACE_CLOSE ||
  			     cur->left != NULL))
  				break;
  		if (cur == NULL) {
  			mandoc_msg(MANDOCERR_BLK_NOTOPEN, ep->node->line,
  			    ep->node->pos, "%s", eqn_toks[tok]);
  			break;
  		}
  		parent = cur;
  		if (EQN_TOK_RIGHT == tok) {
  			if (eqn_next(ep, MODE_SUB) == EQN_TOK_EOF) {
  				mandoc_msg(MANDOCERR_REQ_EMPTY,
  				    ep->node->line, ep->node->pos,
  				    "%s", eqn_toks[tok]);
  				break;
  			}
  			/* Handling depends on right/left. */
  			if (STRNEQ(ep->start, ep->toksz, "ceiling", 7))
  				parent->right = mandoc_strdup("\\[rc]");
  			else if (STRNEQ(ep->start, ep->toksz, "floor", 5))
  				parent->right = mandoc_strdup("\\[rf]");
  			else
  				parent->right =
  				    mandoc_strndup(ep->start, ep->toksz);
  		}
  		parent = parent->parent;
  		if (tok == EQN_TOK_BRACE_CLOSE &&
  		    (parent->type == EQN_PILE ||
  		     parent->type == EQN_MATRIX))
  			parent = parent->parent;
  		/* Close out any "singleton" lists. */
  		while (parent->type == EQN_LIST &&
  		    parent->expectargs == 1 &&
  		    parent->args == 1)
  			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 &&
  		    eqn_next(ep, MODE_SUB) == EQN_TOK_EOF) {
  			mandoc_msg(MANDOCERR_REQ_EMPTY, ep->node->line,
  			    ep->node->pos, "%s", eqn_toks[tok]);
  			break;
  		}
  		parent = eqn_box_alloc(ep, parent);
  		parent->type = EQN_LIST;
  		if (EQN_TOK_LEFT == tok) {
  			if (STRNEQ(ep->start, ep->toksz, "ceiling", 7))
  				parent->left = mandoc_strdup("\\[lc]");
  			else if (STRNEQ(ep->start, ep->toksz, "floor", 5))
  				parent->left = mandoc_strdup("\\[lf]");
  			else
  				parent->left =
  				    mandoc_strndup(ep->start, ep->toksz);
  		}
  		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->node->line,
  			    ep->node->pos, "%s", 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:
  		return;
  	case EQN_TOK__MAX:
  	case EQN_TOK_FUNC:
  	case EQN_TOK_QUOTED:
  	case EQN_TOK_SYM:
  		p = ep->start;
  		assert(p != NULL);
  		/*
  		 * 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;
  		cur->text = p;
  		switch (tok) {
  		case EQN_TOK_FUNC:
  			cur->font = EQNFONT_ROMAN;
  			break;
  		case EQN_TOK_QUOTED:
  			if (cur->font == EQNFONT_NONE)
  				cur->font = EQNFONT_ITALIC;
  			break;
  		case EQN_TOK_SYM:
  			break;
  		default:
  			if (cur->font != EQNFONT_NONE || *p == '\0')
  				break;
  			cpn = p - 1;
  			ccln = CCL_LET;
  			split = NULL;
  			for (;;) {
  				/* Advance to next character. */
  				cp = cpn++;
  				ccl = ccln;
  				ccln = isalpha((unsigned char)*cpn) ? CCL_LET :
  				    isdigit((unsigned char)*cpn) ||
  				    (*cpn == '.' && (ccl == CCL_DIG ||
  				     isdigit((unsigned char)cpn[1]))) ?
  				    CCL_DIG : CCL_PUN;
  				/* No boundary before first character. */
  				if (cp < p)
  					continue;
  				cur->font = ccl == CCL_LET ?
  				    EQNFONT_ITALIC : EQNFONT_ROMAN;
  				if (*cp == '\\')
  					mandoc_escape(&cpn, NULL, NULL);
  				/* No boundary after last character. */
  				if (*cpn == '\0')
  					break;
  				if (ccln == ccl && *cp != ',' && *cpn != ',')
  					continue;
  				/* Boundary found, split the text. */
  				if (parent->args == parent->expectargs) {
  					/* Remove the text from the tree. */
  					if (cur->prev == NULL)
  						parent->first = cur->next;
  					else
  						cur->prev->next = NULL;
  					parent->last = cur->prev;
  					parent->args--;
  					/* Set up a list instead. */
  					split = eqn_box_alloc(ep, parent);
  					split->type = EQN_LIST;
  					/* Insert the word into the list. */
  					split->first = split->last = cur;
  					cur->parent = split;
  					cur->prev = NULL;
  					parent = split;
  				}
  				/* Append a new text box. */
  				nbox = eqn_box_alloc(ep, parent);
  				nbox->type = EQN_TEXT;
  				nbox->text = mandoc_strdup(cpn);
  				/* Truncate the old box. */
  				p = mandoc_strndup(cur->text,
  				    cpn - cur->text);
  				free(cur->text);
  				cur->text = p;
  				/* Setup to process the new box. */
  				cur = nbox;
  				p = nbox->text;
  				cpn = p - 1;
  				ccln = CCL_LET;
  			}
  			if (split != NULL)
  				parent = split->parent;
  			break;
  		}
  		break;
  	default:
  		abort();
  	}
  	goto next_tok;
  }
  
  void
  eqn_free(struct eqn_node *p)
  {
  	int		 i;
  
  	if (p == NULL)
  		return;
  
  	for (i = 0; i < (int)p->defsz; i++) {
  		free(p->defs[i].key);
  		free(p->defs[i].val);
  	}
  
  	free(p->data);
  	free(p->defs);
  	free(p);
  }