===================================================================
RCS file: /cvs/mandoc/eqn.c,v
retrieving revision 1.6
retrieving revision 1.28
diff -u -p -r1.6 -r1.28
--- mandoc/eqn.c	2011/07/17 12:13:37	1.6
+++ mandoc/eqn.c	2011/07/22 14:26:32	1.28
@@ -1,4 +1,4 @@
-/*	$Id: eqn.c,v 1.6 2011/07/17 12:13:37 kristaps Exp $ */
+/*	$Id: eqn.c,v 1.28 2011/07/22 14:26:32 kristaps Exp $ */
 /*
  * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  *
@@ -19,6 +19,7 @@
 #endif
 
 #include <assert.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -28,161 +29,761 @@
 #include "libmandoc.h"
 #include "libroff.h"
 
-static const char	*eqn_nexttok(struct mparse *, int, int,
-				const char **, size_t *);
+#define	EQN_NEST_MAX	 128 /* maximum nesting of defines */
+#define	EQN_MSG(t, x)	 mandoc_msg((t), (x)->parse, (x)->eqn.ln, (x)->eqn.pos, NULL)
 
+enum	eqn_rest {
+	EQN_DESCOPE,
+	EQN_ERR,
+	EQN_OK,
+	EQN_EOF
+};
+
+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	eqnstr {
+	const char	*name;
+	size_t		 sz;
+};
+
+#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))
+
+struct	eqnpart {
+	struct eqnstr	 str;
+	int		(*fp)(struct eqn_node *);
+};
+
+struct	eqnsym {
+	struct eqnstr	 str;
+	const char	*sym;
+};
+
+enum	eqnpartt {
+	EQN_DEFINE = 0,
+	EQN_SET,
+	EQN_UNDEF,
+	EQN__MAX
+};
+
+static	enum eqn_rest	 eqn_box(struct eqn_node *, struct eqn_box *);
+static	struct eqn_box	*eqn_box_alloc(struct eqn_box *);
+static	void		 eqn_box_free(struct eqn_box *);
+static	struct eqn_def	*eqn_def_find(struct eqn_node *, 
+				const char *, size_t);
+static	int		 eqn_do_define(struct eqn_node *);
+static	int		 eqn_do_set(struct eqn_node *);
+static	int		 eqn_do_undef(struct eqn_node *);
+static	enum eqn_rest	 eqn_eqn(struct eqn_node *, struct eqn_box *);
+static	enum eqn_rest	 eqn_list(struct eqn_node *, struct eqn_box *);
+static	const char	*eqn_nexttok(struct eqn_node *, size_t *);
+static	const char	*eqn_nextrawtok(struct eqn_node *, size_t *);
+static	const char	*eqn_next(struct eqn_node *, 
+				char, size_t *, int);
+static	void		 eqn_rewind(struct eqn_node *);
+
+static	const struct eqnpart eqnparts[EQN__MAX] = {
+	{ { "define", 6 }, eqn_do_define }, /* EQN_DEFINE */
+	{ { "set", 3 }, eqn_do_set }, /* EQN_SET */
+	{ { "undef", 5 }, eqn_do_undef }, /* EQN_UNDEF */
+};
+
+static	const struct eqnstr eqnmarks[EQNMARK__MAX] = {
+	{ "", 0 }, /* EQNMARK_NONE */
+	{ "dot", 3 }, /* EQNMARK_DOT */
+	{ "dotdot", 6 }, /* EQNMARK_DOTDOT */
+	{ "hat", 3 }, /* EQNMARK_HAT */
+	{ "tilde", 5 }, /* EQNMARK_TILDE */
+	{ "vec", 3 }, /* EQNMARK_VEC */
+	{ "dyad", 4 }, /* EQNMARK_DYAD */
+	{ "bar", 3 }, /* EQNMARK_BAR */
+	{ "under", 5 }, /* EQNMARK_UNDER */
+};
+
+static	const struct eqnstr eqnfonts[EQNFONT__MAX] = {
+	{ "", 0 }, /* EQNFONT_NONE */
+	{ "roman", 5 }, /* EQNFONT_ROMAN */
+	{ "bold", 4 }, /* EQNFONT_BOLD */
+	{ "italic", 6 }, /* EQNFONT_ITALIC */
+};
+
+static	const struct eqnstr eqnposs[EQNPOS__MAX] = {
+	{ "", 0 }, /* EQNPOS_NONE */
+	{ "over", 4 }, /* EQNPOS_OVER */
+	{ "sup", 3 }, /* EQNPOS_SUP */
+	{ "sub", 3 }, /* EQNPOS_SUB */
+	{ "to", 2 }, /* EQNPOS_TO */
+	{ "from", 4 }, /* EQNPOS_FROM */
+};
+
+static	const struct eqnstr eqnpiles[EQNPILE__MAX] = {
+	{ "", 0 }, /* EQNPILE_NONE */
+	{ "cpile", 5 }, /* EQNPILE_CPILE */
+	{ "rpile", 5 }, /* EQNPILE_RPILE */
+	{ "lpile", 5 }, /* EQNPILE_LPILE */
+};
+
+static	const struct eqnsym eqnsyms[EQNSYM__MAX] = {
+	{ { "alpha", 5 }, "*a" }, /* EQNSYM_alpha */
+	{ { "beta", 4 }, "*b" }, /* EQNSYM_beta */
+	{ { "chi", 3 }, "*x" }, /* EQNSYM_chi */
+	{ { "delta", 5 }, "*d" }, /* EQNSYM_delta */
+	{ { "epsilon", 7 }, "*e" }, /* EQNSYM_epsilon */
+	{ { "eta", 3 }, "*y" }, /* EQNSYM_eta */
+	{ { "gamma", 5 }, "*g" }, /* EQNSYM_gamma */
+	{ { "iota", 4 }, "*i" }, /* EQNSYM_iota */
+	{ { "kappa", 5 }, "*k" }, /* EQNSYM_kappa */
+	{ { "lambda", 6 }, "*l" }, /* EQNSYM_lambda */
+	{ { "mu", 2 }, "*m" }, /* EQNSYM_mu */
+	{ { "nu", 2 }, "*n" }, /* EQNSYM_nu */
+	{ { "omega", 5 }, "*w" }, /* EQNSYM_omega */
+	{ { "omicron", 7 }, "*o" }, /* EQNSYM_omicron */
+	{ { "phi", 3 }, "*f" }, /* EQNSYM_phi */
+	{ { "pi", 2 }, "*p" }, /* EQNSYM_pi */
+	{ { "psi", 2 }, "*q" }, /* EQNSYM_psi */
+	{ { "rho", 3 }, "*r" }, /* EQNSYM_rho */
+	{ { "sigma", 5 }, "*s" }, /* EQNSYM_sigma */
+	{ { "tau", 3 }, "*t" }, /* EQNSYM_tau */
+	{ { "theta", 5 }, "*h" }, /* EQNSYM_theta */
+	{ { "upsilon", 7 }, "*u" }, /* EQNSYM_upsilon */
+	{ { "xi", 2 }, "*c" }, /* EQNSYM_xi */
+	{ { "zeta", 4 }, "*z" }, /* EQNSYM_zeta */
+	{ { "DELTA", 5 }, "*D" }, /* EQNSYM_DELTA */
+	{ { "GAMMA", 5 }, "*G" }, /* EQNSYM_GAMMA */
+	{ { "LAMBDA", 6 }, "*L" }, /* EQNSYM_LAMBDA */
+	{ { "OMEGA", 5 }, "*W" }, /* EQNSYM_OMEGA */
+	{ { "PHI", 3 }, "*F" }, /* EQNSYM_PHI */
+	{ { "PI", 2 }, "*P" }, /* EQNSYM_PI */
+	{ { "PSI", 3 }, "*Q" }, /* EQNSYM_PSI */
+	{ { "SIGMA", 5 }, "*S" }, /* EQNSYM_SIGMA */
+	{ { "THETA", 5 }, "*H" }, /* EQNSYM_THETA */
+	{ { "UPSILON", 7 }, "*U" }, /* EQNSYM_UPSILON */
+	{ { "XI", 2 }, "*C" }, /* EQNSYM_XI */
+	{ { "inter", 5 }, "ca" }, /* EQNSYM_inter */
+	{ { "union", 5 }, "cu" }, /* EQNSYM_union */
+	{ { "prod", 4 }, "product" }, /* EQNSYM_prod */
+	{ { "int", 3 }, "integral" }, /* EQNSYM_int */
+	{ { "sum", 3 }, "sum" }, /* EQNSYM_sum */
+	{ { "grad", 4 }, "gr" }, /* EQNSYM_grad */
+	{ { "del", 3 }, "gr" }, /* EQNSYM_del */
+	{ { "times", 5 }, "mu" }, /* EQNSYM_times */
+	{ { "cdot", 4 }, "pc" }, /* EQNSYM_cdot */
+	{ { "nothing", 7 }, "&" }, /* EQNSYM_nothing */
+	{ { "approx", 6 }, "~~" }, /* EQNSYM_approx */
+	{ { "prime", 5 }, "aq" }, /* EQNSYM_prime */
+	{ { "half", 4 }, "12" }, /* EQNSYM_half */
+	{ { "partial", 7 }, "pd" }, /* EQNSYM_partial */
+	{ { "inf", 3 }, "if" }, /* EQNSYM_inf */
+	{ { ">>", 2 }, ">>" }, /* EQNSYM_muchgreat */
+	{ { "<<", 2 }, "<<" }, /* EQNSYM_muchless */
+	{ { "<-", 2 }, "<-" }, /* EQNSYM_larrow */
+	{ { "->", 2 }, "->" }, /* EQNSYM_rarrow */
+	{ { "+-", 2 }, "+-" }, /* EQNSYM_pm */
+	{ { "!=", 2 }, "!=" }, /* EQNSYM_nequal */
+	{ { "==", 2 }, "==" }, /* EQNSYM_equiv */
+	{ { "<=", 2 }, "<=" }, /* EQNSYM_lessequal */
+	{ { ">=", 2 }, ">=" }, /* EQNSYM_moreequal */
+};
+
 /* ARGSUSED */
 enum rofferr
 eqn_read(struct eqn_node **epp, int ln, 
 		const char *p, int pos, int *offs)
 {
-	size_t		  sz;
-	struct eqn_node	 *ep;
-	const char	 *start, *end;
-	int		  i;
+	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 == strcmp(p, ".EN")) {
+		er = eqn_end(ep);
 		*epp = NULL;
-		return(ROFF_EQN);
+		return(er);
 	}
 
-	ep = *epp;
-	end = p + pos;
-	start = eqn_nexttok(ep->parse, ln, pos, &end, &sz);
+	/*
+	 * Build up the full string, replacing all newlines with regular
+	 * whitespace.
+	 */
 
-	if (NULL == start)
-		return(ROFF_IGN);
+	sz = strlen(p + pos) + 1;
+	ep->data = mandoc_realloc(ep->data, ep->sz + sz + 1);
 
-	if (6 == sz && 0 == strncmp("define", start, 6)) {
-		/* 
-		 * TODO: warn if key is quoted: groff doesn't seem to
-		 * like this (I don't know why).
-		 */
-		start = eqn_nexttok(ep->parse, ln, pos, &end, &sz);
-		for (i = 0; i < (int)ep->defsz; i++)  {
-			if (ep->defs[i].keysz != sz)
-				continue;
-			if (0 == strncmp(ep->defs[i].key, start, sz))
-				break;
-		}
+	/* First invocation: nil terminate the string. */
 
-		/*
-		 * TODO: merge this code with roff_getstr().
-		 */
+	if (0 == ep->sz)
+		*ep->data = '\0';
 
-		if (i == (int)ep->defsz) {
-			ep->defsz++;
-			ep->defs = mandoc_realloc
-				(ep->defs, ep->defsz * 
-				 sizeof(struct eqn_def));
-			ep->defs[i].keysz = sz;
-			ep->defs[i].key = mandoc_malloc(sz + 1);
-			memcpy(ep->defs[i].key, start, sz);
-			ep->defs[i].key[(int)sz] = '\0';
-			ep->defs[i].val = NULL;
-			ep->defs[i].valsz = 0;
-		}
+	ep->sz += sz;
+	strlcat(ep->data, p + pos, ep->sz + 1);
+	strlcat(ep->data, " ", ep->sz + 1);
+	return(ROFF_IGN);
+}
 
-		start = eqn_nexttok(ep->parse, ln, pos, &end, &sz);
+struct eqn_node *
+eqn_alloc(int pos, int line, struct mparse *parse)
+{
+	struct eqn_node	*p;
 
-		ep->defs[i].valsz = sz;
-		ep->defs[i].val = mandoc_realloc
-			(ep->defs[i].val, sz + 1);
-		memcpy(ep->defs[i].val, start, sz);
-		ep->defs[i].val[(int)sz] = '\0';
+	p = mandoc_calloc(1, sizeof(struct eqn_node));
+	p->parse = parse;
+	p->eqn.ln = line;
+	p->eqn.pos = pos;
 
-		if ('\0' == *end)
-			return(ROFF_IGN);
+	return(p);
+}
 
-		*offs = end - (p + pos);
-		assert(*offs > 0);
+enum rofferr
+eqn_end(struct eqn_node *ep)
+{
+	struct eqn_box	*root;
+	enum eqn_rest	 c;
 
-		return(ROFF_RERUN);
-	}  else
-		end = p + pos;
+	ep->eqn.root = mandoc_calloc(1, sizeof(struct eqn_box));
 
-	if (0 == (sz = strlen(end)))
+	root = ep->eqn.root;
+	root->type = EQN_ROOT;
+
+	if (0 == ep->sz)
 		return(ROFF_IGN);
 
-	ep->eqn.data = mandoc_realloc(ep->eqn.data, ep->eqn.sz + sz + 1);
-	if (0 == ep->eqn.sz)
-		*ep->eqn.data = '\0';
+	if (EQN_DESCOPE == (c = eqn_eqn(ep, root))) {
+		EQN_MSG(MANDOCERR_EQNNSCOPE, ep);
+		c = EQN_ERR;
+	}
 
-	ep->eqn.sz += sz;
-	strlcat(ep->eqn.data, end, ep->eqn.sz + 1);
-	return(ROFF_IGN);
+	return(EQN_EOF == c ? ROFF_EQN : ROFF_IGN);
 }
 
-struct eqn_node *
-eqn_alloc(int pos, int line, struct mparse *parse)
+static enum eqn_rest
+eqn_eqn(struct eqn_node *ep, struct eqn_box *last)
 {
-	struct eqn_node	*p;
+	struct eqn_box	*bp;
+	enum eqn_rest	 c;
 
-	p = mandoc_calloc(1, sizeof(struct eqn_node));
-	p->parse = parse;
-	p->eqn.line = line;
-	p->eqn.pos = pos;
+	bp = eqn_box_alloc(last);
+	bp->type = EQN_SUBEXPR;
 
-	return(p);
+	while (EQN_OK == (c = eqn_box(ep, bp)))
+		/* Spin! */ ;
+
+	return(c);
 }
 
-/* ARGSUSED */
-void
-eqn_end(struct eqn_node *e)
+static enum eqn_rest
+eqn_list(struct eqn_node *ep, struct eqn_box *last)
 {
+	struct eqn_box	*bp;
+	const char	*start;
+	size_t		 sz;
+	enum eqn_rest	 c;
 
-	/* Nothing to do. */
+	bp = eqn_box_alloc(last);
+	bp->type = EQN_LIST;
+
+	if (NULL == (start = eqn_nexttok(ep, &sz))) {
+		EQN_MSG(MANDOCERR_EQNEOF, ep);
+		return(EQN_ERR);
+	}
+	if ( ! STRNEQ(start, sz, "{", 1)) {
+		EQN_MSG(MANDOCERR_EQNSYNT, ep);
+		return(EQN_ERR);
+	}
+
+	while (EQN_DESCOPE == (c = eqn_eqn(ep, bp))) {
+		eqn_rewind(ep);
+		start = eqn_nexttok(ep, &sz);
+		assert(start);
+		if ( ! STRNEQ(start, sz, "above", 5))
+			break;
+		bp->last->above = 1;
+	}
+
+	if (EQN_DESCOPE != c) {
+		if (EQN_ERR != c)
+			EQN_MSG(MANDOCERR_EQNSCOPE, ep);
+		return(EQN_ERR);
+	}
+
+	eqn_rewind(ep);
+	start = eqn_nexttok(ep, &sz);
+	assert(start);
+	if (STRNEQ(start, sz, "}", 1))
+		return(EQN_OK);
+
+	EQN_MSG(MANDOCERR_EQNBADSCOPE, ep);
+	return(EQN_ERR);
 }
 
+static enum eqn_rest
+eqn_box(struct eqn_node *ep, struct eqn_box *last)
+{
+	size_t		 sz;
+	const char	*start;
+	char		*left;
+	char		 sym[64];
+	enum eqn_rest	 c;
+	int		 i, size;
+	struct eqn_box	*bp;
+
+	if (NULL == (start = eqn_nexttok(ep, &sz)))
+		return(EQN_EOF);
+
+	if (STRNEQ(start, sz, "}", 1))
+		return(EQN_DESCOPE);
+	else if (STRNEQ(start, sz, "right", 5))
+		return(EQN_DESCOPE);
+	else if (STRNEQ(start, sz, "above", 5))
+		return(EQN_DESCOPE);
+
+	for (i = 0; i < (int)EQN__MAX; i++) {
+		if ( ! EQNSTREQ(&eqnparts[i].str, start, sz))
+			continue;
+		return((*eqnparts[i].fp)(ep) ? EQN_OK : EQN_ERR);
+	} 
+
+	if (STRNEQ(start, sz, "{", 1)) {
+		if (EQN_DESCOPE != (c = eqn_eqn(ep, last))) {
+			if (EQN_ERR != c)
+				EQN_MSG(MANDOCERR_EQNSCOPE, ep);
+			return(EQN_ERR);
+		}
+		eqn_rewind(ep);
+		start = eqn_nexttok(ep, &sz);
+		assert(start);
+		if (STRNEQ(start, sz, "}", 1))
+			return(EQN_OK);
+		EQN_MSG(MANDOCERR_EQNBADSCOPE, ep);
+		return(EQN_ERR);
+	} 
+
+	for (i = 0; i < (int)EQNPILE__MAX; i++) {
+		if ( ! EQNSTREQ(&eqnpiles[i], start, sz))
+			continue;
+		if (EQN_OK == (c = eqn_list(ep, last)))
+			last->last->pile = (enum eqn_pilet)i;
+		return(c);
+	}
+
+	if (STRNEQ(start, sz, "left", 4)) {
+		if (NULL == (start = eqn_nexttok(ep, &sz))) {
+			EQN_MSG(MANDOCERR_EQNEOF, ep);
+			return(EQN_ERR);
+		}
+		left = mandoc_strndup(start, sz);
+		c = eqn_eqn(ep, last);
+		if (last->last)
+			last->last->left = left;
+		else
+			free(left);
+		if (EQN_DESCOPE != c)
+			return(c);
+		assert(last->last);
+		eqn_rewind(ep);
+		start = eqn_nexttok(ep, &sz);
+		assert(start);
+		if ( ! STRNEQ(start, sz, "right", 5))
+			return(EQN_DESCOPE);
+		if (NULL == (start = eqn_nexttok(ep, &sz))) {
+			EQN_MSG(MANDOCERR_EQNEOF, ep);
+			return(EQN_ERR);
+		}
+		last->last->right = mandoc_strndup(start, sz);
+		return(EQN_OK);
+	}
+
+	for (i = 0; i < (int)EQNPOS__MAX; i++) {
+		if ( ! EQNSTREQ(&eqnposs[i], start, sz))
+			continue;
+		if (NULL == last->last) {
+			EQN_MSG(MANDOCERR_EQNSYNT, ep);
+			return(EQN_ERR);
+		} 
+		last->last->pos = (enum eqn_post)i;
+		if (EQN_EOF == (c = eqn_box(ep, last))) {
+			EQN_MSG(MANDOCERR_EQNEOF, ep);
+			return(EQN_ERR);
+		}
+		return(c);
+	}
+
+	for (i = 0; i < (int)EQNMARK__MAX; i++) {
+		if ( ! EQNSTREQ(&eqnmarks[i], start, sz))
+			continue;
+		if (NULL == last->last) {
+			EQN_MSG(MANDOCERR_EQNSYNT, ep);
+			return(EQN_ERR);
+		} 
+		last->last->mark = (enum eqn_markt)i;
+		if (EQN_EOF == (c = eqn_box(ep, last))) {
+			EQN_MSG(MANDOCERR_EQNEOF, ep);
+			return(EQN_ERR);
+		}
+		return(c);
+	}
+
+	for (i = 0; i < (int)EQNFONT__MAX; i++) {
+		if ( ! EQNSTREQ(&eqnfonts[i], start, sz))
+			continue;
+		if (EQN_EOF == (c = eqn_box(ep, last))) {
+			EQN_MSG(MANDOCERR_EQNEOF, ep);
+			return(EQN_ERR);
+		} else if (EQN_OK == c)
+			last->last->font = (enum eqn_fontt)i;
+		return(c);
+	}
+
+	if (STRNEQ(start, sz, "size", 4)) {
+		if (NULL == (start = eqn_nexttok(ep, &sz))) {
+			EQN_MSG(MANDOCERR_EQNEOF, ep);
+			return(EQN_ERR);
+		}
+		size = mandoc_strntoi(start, sz, 10);
+		if (EQN_EOF == (c = eqn_box(ep, last))) {
+			EQN_MSG(MANDOCERR_EQNEOF, ep);
+			return(EQN_ERR);
+		} else if (EQN_OK != c)
+			return(c);
+		last->last->size = size;
+	}
+
+	bp = eqn_box_alloc(last);
+	bp->type = EQN_TEXT;
+	for (i = 0; i < (int)EQNSYM__MAX; i++)
+		if (EQNSTREQ(&eqnsyms[i].str, start, sz)) {
+			sym[63] = '\0';
+			snprintf(sym, 62, "\\[%s]", eqnsyms[i].sym);
+			bp->text = mandoc_strdup(sym);
+			return(EQN_OK);
+		}
+
+	bp->text = mandoc_strndup(start, sz);
+	return(EQN_OK);
+}
+
 void
 eqn_free(struct eqn_node *p)
 {
 	int		 i;
 
-	free(p->eqn.data);
+	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->data);
 	free(p->defs);
 	free(p);
 }
 
+static struct eqn_box *
+eqn_box_alloc(struct eqn_box *parent)
+{
+	struct eqn_box	*bp;
+
+	bp = mandoc_calloc(1, sizeof(struct eqn_box));
+	bp->parent = parent;
+	bp->size = EQN_DEFSIZE;
+
+	if (NULL == parent->first)
+		parent->first = bp;
+	else
+		parent->last->next = bp;
+
+	parent->last = bp;
+	return(bp);
+}
+
+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);
+}
+
 static const char *
-eqn_nexttok(struct mparse *mp, int ln, int pos,
-		const char **next, size_t *sz)
+eqn_nextrawtok(struct eqn_node *ep, size_t *sz)
 {
-	const char	*start;
-	int		 q;
 
-	start = *next;
+	return(eqn_next(ep, '"', sz, 0));
+}
+
+static const char *
+eqn_nexttok(struct eqn_node *ep, size_t *sz)
+{
+
+	return(eqn_next(ep, '"', sz, 1));
+}
+
+static void
+eqn_rewind(struct eqn_node *ep)
+{
+
+	ep->cur = ep->rew;
+}
+
+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_EQNNEST, ep);
+		return(NULL);
+	}
+
+	ep->cur = ep->rew;
+	start = &ep->data[(int)ep->cur];
 	q = 0;
 
 	if ('\0' == *start)
 		return(NULL);
 
-	if ('"' == *start) {
-		start++;
+	if (quote == *start) {
+		ep->cur++;
 		q = 1;
 	}
 
-	*next = q ? strchr(start, '"') : strchr(start, ' ');
+	start = &ep->data[(int)ep->cur];
 
-	if (NULL != *next) {
-		*sz = (size_t)(*next - start);
+	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)
-			(*next)++;
-		while (' ' == **next)
-			(*next)++;
+			ep->cur++;
+		while (' ' == ep->data[(int)ep->cur] ||
+				'\t' == ep->data[(int)ep->cur] ||
+				'~' == ep->data[(int)ep->cur])
+			ep->cur++;
 	} else {
 		if (q)
-			mandoc_msg(MANDOCERR_BADQUOTE, 
-					mp, ln, pos, NULL);
-		*next = strchr(start, '\0');
-		*sz = (size_t)(*next - start);
+			EQN_MSG(MANDOCERR_BADQUOTE, 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);
+}
+
+static int
+eqn_do_set(struct eqn_node *ep)
+{
+	const char	*start;
+
+	if (NULL == (start = eqn_nextrawtok(ep, NULL)))
+		EQN_MSG(MANDOCERR_EQNARGS, ep);
+	else if (NULL == (start = eqn_nextrawtok(ep, NULL)))
+		EQN_MSG(MANDOCERR_EQNARGS, ep);
+	else
+		return(1);
+
+	return(0);
+}
+
+static int
+eqn_do_define(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_EQNARGS, 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_realloc
+				(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_EQNARGS, ep);
+		return(0);
+	}
+
+	def->valsz = sz;
+	def->val = mandoc_realloc(def->val, sz + 1);
+	memcpy(def->val, start, sz);
+	def->val[(int)sz] = '\0';
+	return(1);
+}
+
+static int
+eqn_do_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_EQNARGS, ep);
+		return(0);
+	} else if (NULL != (def = eqn_def_find(ep, start, sz)))
+		def->keysz = 0;
+
+	return(1);
+}
+
+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);
 }