Merge mandoc from vendor into contrib and provide the necessary Makefile glue.

It's not yet connected to the build.

1 files changed, 1768 insertions, 0 deletions

diff --git a/contrib/mdocml/roff.c b/contrib/mdocml/roff.c
new file mode 100644
index 0000000..b479cc2
--- /dev/null
+++ b/contrib/mdocml/roff.c
@@ -0,0 +1,1768 @@
+/*	$Id: roff.c,v 1.172 2011/10/24 21:41:45 schwarze Exp $ */
+/*
+ * Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
+ * Copyright (c) 2010, 2011 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 AUTHORS DISCLAIM ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS 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 <assert.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mandoc.h"
+#include "libroff.h"
+#include "libmandoc.h"
+
+/* Maximum number of nested if-else conditionals. */
+#define	RSTACK_MAX	128
+
+/* Maximum number of string expansions per line, to break infinite loops. */
+#define	EXPAND_LIMIT	1000
+
+enum	rofft {
+	ROFF_ad,
+	ROFF_am,
+	ROFF_ami,
+	ROFF_am1,
+	ROFF_de,
+	ROFF_dei,
+	ROFF_de1,
+	ROFF_ds,
+	ROFF_el,
+	ROFF_hy,
+	ROFF_ie,
+	ROFF_if,
+	ROFF_ig,
+	ROFF_it,
+	ROFF_ne,
+	ROFF_nh,
+	ROFF_nr,
+	ROFF_ns,
+	ROFF_ps,
+	ROFF_rm,
+	ROFF_so,
+	ROFF_ta,
+	ROFF_tr,
+	ROFF_TS,
+	ROFF_TE,
+	ROFF_T_,
+	ROFF_EQ,
+	ROFF_EN,
+	ROFF_cblock,
+	ROFF_ccond,
+	ROFF_USERDEF,
+	ROFF_MAX
+};
+
+enum	roffrule {
+	ROFFRULE_ALLOW,
+	ROFFRULE_DENY
+};
+
+/*
+ * A single register entity.  If "set" is zero, the value of the
+ * register should be the default one, which is per-register.
+ * Registers are assumed to be unsigned ints for now.
+ */
+struct	reg {
+	int		 set; /* whether set or not */
+	unsigned int	 u; /* unsigned integer */
+};
+
+/*
+ * An incredibly-simple string buffer.
+ */
+struct	roffstr {
+	char		*p; /* nil-terminated buffer */
+	size_t		 sz; /* saved strlen(p) */
+};
+
+/*
+ * A key-value roffstr pair as part of a singly-linked list.
+ */
+struct	roffkv {
+	struct roffstr	 key;
+	struct roffstr	 val;
+	struct roffkv	*next; /* next in list */
+};
+
+struct	roff {
+	struct mparse	*parse; /* parse point */
+	struct roffnode	*last; /* leaf of stack */
+	enum roffrule	 rstack[RSTACK_MAX]; /* stack of !`ie' rules */
+	int		 rstackpos; /* position in rstack */
+	struct reg	 regs[REG__MAX];
+	struct roffkv	*strtab; /* user-defined strings & macros */
+	struct roffkv	*xmbtab; /* multi-byte trans table (`tr') */
+	struct roffstr	*xtab; /* single-byte trans table (`tr') */
+	const char	*current_string; /* value of last called user macro */
+	struct tbl_node	*first_tbl; /* first table parsed */
+	struct tbl_node	*last_tbl; /* last table parsed */
+	struct tbl_node	*tbl; /* current table being parsed */
+	struct eqn_node	*last_eqn; /* last equation parsed */
+	struct eqn_node	*first_eqn; /* first equation parsed */
+	struct eqn_node	*eqn; /* current equation being parsed */
+};
+
+struct	roffnode {
+	enum rofft	 tok; /* type of node */
+	struct roffnode	*parent; /* up one in stack */
+	int		 line; /* parse line */
+	int		 col; /* parse col */
+	char		*name; /* node name, e.g. macro name */
+	char		*end; /* end-rules: custom token */
+	int		 endspan; /* end-rules: next-line or infty */
+	enum roffrule	 rule; /* current evaluation rule */
+};
+
+#define	ROFF_ARGS	 struct roff *r, /* parse ctx */ \
+			 enum rofft tok, /* tok of macro */ \
+		 	 char **bufp, /* input buffer */ \
+			 size_t *szp, /* size of input buffer */ \
+			 int ln, /* parse line */ \
+			 int ppos, /* original pos in buffer */ \
+			 int pos, /* current pos in buffer */ \
+			 int *offs /* reset offset of buffer data */
+
+typedef	enum rofferr (*roffproc)(ROFF_ARGS);
+
+struct	roffmac {
+	const char	*name; /* macro name */
+	roffproc	 proc; /* process new macro */
+	roffproc	 text; /* process as child text of macro */
+	roffproc	 sub; /* process as child of macro */
+	int		 flags;
+#define	ROFFMAC_STRUCT	(1 << 0) /* always interpret */
+	struct roffmac	*next;
+};
+
+struct	predef {
+	const char	*name; /* predefined input name */
+	const char	*str; /* replacement symbol */
+};
+
+#define	PREDEF(__name, __str) \
+	{ (__name), (__str) },
+
+static	enum rofft	 roffhash_find(const char *, size_t);
+static	void		 roffhash_init(void);
+static	void		 roffnode_cleanscope(struct roff *);
+static	void		 roffnode_pop(struct roff *);
+static	void		 roffnode_push(struct roff *, enum rofft,
+				const char *, int, int);
+static	enum rofferr	 roff_block(ROFF_ARGS);
+static	enum rofferr	 roff_block_text(ROFF_ARGS);
+static	enum rofferr	 roff_block_sub(ROFF_ARGS);
+static	enum rofferr	 roff_cblock(ROFF_ARGS);
+static	enum rofferr	 roff_ccond(ROFF_ARGS);
+static	enum rofferr	 roff_cond(ROFF_ARGS);
+static	enum rofferr	 roff_cond_text(ROFF_ARGS);
+static	enum rofferr	 roff_cond_sub(ROFF_ARGS);
+static	enum rofferr	 roff_ds(ROFF_ARGS);
+static	enum roffrule	 roff_evalcond(const char *, int *);
+static	void		 roff_free1(struct roff *);
+static	void		 roff_freestr(struct roffkv *);
+static	char		*roff_getname(struct roff *, char **, int, int);
+static	const char	*roff_getstrn(const struct roff *, 
+				const char *, size_t);
+static	enum rofferr	 roff_line_ignore(ROFF_ARGS);
+static	enum rofferr	 roff_nr(ROFF_ARGS);
+static	void		 roff_openeqn(struct roff *, const char *,
+				int, int, const char *);
+static	enum rofft	 roff_parse(struct roff *, const char *, int *);
+static	enum rofferr	 roff_parsetext(char *);
+static	enum rofferr	 roff_res(struct roff *, 
+				char **, size_t *, int, int);
+static	enum rofferr	 roff_rm(ROFF_ARGS);
+static	void		 roff_setstr(struct roff *,
+				const char *, const char *, int);
+static	void		 roff_setstrn(struct roffkv **, const char *, 
+				size_t, const char *, size_t, int);
+static	enum rofferr	 roff_so(ROFF_ARGS);
+static	enum rofferr	 roff_tr(ROFF_ARGS);
+static	enum rofferr	 roff_TE(ROFF_ARGS);
+static	enum rofferr	 roff_TS(ROFF_ARGS);
+static	enum rofferr	 roff_EQ(ROFF_ARGS);
+static	enum rofferr	 roff_EN(ROFF_ARGS);
+static	enum rofferr	 roff_T_(ROFF_ARGS);
+static	enum rofferr	 roff_userdef(ROFF_ARGS);
+
+/* See roffhash_find() */
+
+#define	ASCII_HI	 126
+#define	ASCII_LO	 33
+#define	HASHWIDTH	(ASCII_HI - ASCII_LO + 1)
+
+static	struct roffmac	*hash[HASHWIDTH];
+
+static	struct roffmac	 roffs[ROFF_MAX] = {
+	{ "ad", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "am", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "ami", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "am1", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "de", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "dei", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "de1", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "ds", roff_ds, NULL, NULL, 0, NULL },
+	{ "el", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
+	{ "hy", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "ie", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
+	{ "if", roff_cond, roff_cond_text, roff_cond_sub, ROFFMAC_STRUCT, NULL },
+	{ "ig", roff_block, roff_block_text, roff_block_sub, 0, NULL },
+	{ "it", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "ne", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "nh", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "nr", roff_nr, NULL, NULL, 0, NULL },
+	{ "ns", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "ps", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "rm", roff_rm, NULL, NULL, 0, NULL },
+	{ "so", roff_so, NULL, NULL, 0, NULL },
+	{ "ta", roff_line_ignore, NULL, NULL, 0, NULL },
+	{ "tr", roff_tr, NULL, NULL, 0, NULL },
+	{ "TS", roff_TS, NULL, NULL, 0, NULL },
+	{ "TE", roff_TE, NULL, NULL, 0, NULL },
+	{ "T&", roff_T_, NULL, NULL, 0, NULL },
+	{ "EQ", roff_EQ, NULL, NULL, 0, NULL },
+	{ "EN", roff_EN, NULL, NULL, 0, NULL },
+	{ ".", roff_cblock, NULL, NULL, 0, NULL },
+	{ "\\}", roff_ccond, NULL, NULL, 0, NULL },
+	{ NULL, roff_userdef, NULL, NULL, 0, NULL },
+};
+
+/* Array of injected predefined strings. */
+#define	PREDEFS_MAX	 38
+static	const struct predef predefs[PREDEFS_MAX] = {
+#include "predefs.in"
+};
+
+/* See roffhash_find() */
+#define	ROFF_HASH(p)	(p[0] - ASCII_LO)
+
+static void
+roffhash_init(void)
+{
+	struct roffmac	 *n;
+	int		  buc, i;
+
+	for (i = 0; i < (int)ROFF_USERDEF; i++) {
+		assert(roffs[i].name[0] >= ASCII_LO);
+		assert(roffs[i].name[0] <= ASCII_HI);
+
+		buc = ROFF_HASH(roffs[i].name);
+
+		if (NULL != (n = hash[buc])) {
+			for ( ; n->next; n = n->next)
+				/* Do nothing. */ ;
+			n->next = &roffs[i];
+		} else
+			hash[buc] = &roffs[i];
+	}
+}
+
+/*
+ * Look up a roff token by its name.  Returns ROFF_MAX if no macro by
+ * the nil-terminated string name could be found.
+ */
+static enum rofft
+roffhash_find(const char *p, size_t s)
+{
+	int		 buc;
+	struct roffmac	*n;
+
+	/*
+	 * libroff has an extremely simple hashtable, for the time
+	 * being, which simply keys on the first character, which must
+	 * be printable, then walks a chain.  It works well enough until
+	 * optimised.
+	 */
+
+	if (p[0] < ASCII_LO || p[0] > ASCII_HI)
+		return(ROFF_MAX);
+
+	buc = ROFF_HASH(p);
+
+	if (NULL == (n = hash[buc]))
+		return(ROFF_MAX);
+	for ( ; n; n = n->next)
+		if (0 == strncmp(n->name, p, s) && '\0' == n->name[(int)s])
+			return((enum rofft)(n - roffs));
+
+	return(ROFF_MAX);
+}
+
+
+/*
+ * Pop the current node off of the stack of roff instructions currently
+ * pending.
+ */
+static void
+roffnode_pop(struct roff *r)
+{
+	struct roffnode	*p;
+
+	assert(r->last);
+	p = r->last; 
+
+	r->last = r->last->parent;
+	free(p->name);
+	free(p->end);
+	free(p);
+}
+
+
+/*
+ * Push a roff node onto the instruction stack.  This must later be
+ * removed with roffnode_pop().
+ */
+static void
+roffnode_push(struct roff *r, enum rofft tok, const char *name,
+		int line, int col)
+{
+	struct roffnode	*p;
+
+	p = mandoc_calloc(1, sizeof(struct roffnode));
+	p->tok = tok;
+	if (name)
+		p->name = mandoc_strdup(name);
+	p->parent = r->last;
+	p->line = line;
+	p->col = col;
+	p->rule = p->parent ? p->parent->rule : ROFFRULE_DENY;
+
+	r->last = p;
+}
+
+
+static void
+roff_free1(struct roff *r)
+{
+	struct tbl_node	*t;
+	struct eqn_node	*e;
+	int		 i;
+
+	while (NULL != (t = r->first_tbl)) {
+		r->first_tbl = t->next;
+		tbl_free(t);
+	}
+
+	r->first_tbl = r->last_tbl = r->tbl = NULL;
+
+	while (NULL != (e = r->first_eqn)) {
+		r->first_eqn = e->next;
+		eqn_free(e);
+	}
+
+	r->first_eqn = r->last_eqn = r->eqn = NULL;
+
+	while (r->last)
+		roffnode_pop(r);
+
+	roff_freestr(r->strtab);
+	roff_freestr(r->xmbtab);
+
+	r->strtab = r->xmbtab = NULL;
+
+	if (r->xtab)
+		for (i = 0; i < 128; i++)
+			free(r->xtab[i].p);
+
+	free(r->xtab);
+	r->xtab = NULL;
+}
+
+void
+roff_reset(struct roff *r)
+{
+	int		 i;
+
+	roff_free1(r);
+
+	memset(&r->regs, 0, sizeof(struct reg) * REG__MAX);
+
+	for (i = 0; i < PREDEFS_MAX; i++) 
+		roff_setstr(r, predefs[i].name, predefs[i].str, 0);
+}
+
+
+void
+roff_free(struct roff *r)
+{
+
+	roff_free1(r);
+	free(r);
+}
+
+
+struct roff *
+roff_alloc(struct mparse *parse)
+{
+	struct roff	*r;
+	int		 i;
+
+	r = mandoc_calloc(1, sizeof(struct roff));
+	r->parse = parse;
+	r->rstackpos = -1;
+	
+	roffhash_init();
+
+	for (i = 0; i < PREDEFS_MAX; i++) 
+		roff_setstr(r, predefs[i].name, predefs[i].str, 0);
+
+	return(r);
+}
+
+/*
+ * Pre-filter each and every line for reserved words (one beginning with
+ * `\*', e.g., `\*(ab').  These must be handled before the actual line
+ * is processed. 
+ * This also checks the syntax of regular escapes.
+ */
+static enum rofferr
+roff_res(struct roff *r, char **bufp, size_t *szp, int ln, int pos)
+{
+	enum mandoc_esc	 esc;
+	const char	*stesc;	/* start of an escape sequence ('\\') */
+	const char	*stnam;	/* start of the name, after "[(*" */
+	const char	*cp;	/* end of the name, e.g. before ']' */
+	const char	*res;	/* the string to be substituted */
+	int		 i, maxl, expand_count;
+	size_t		 nsz;
+	char		*n;
+
+	expand_count = 0;
+
+again:
+	cp = *bufp + pos;
+	while (NULL != (cp = strchr(cp, '\\'))) {
+		stesc = cp++;
+
+		/*
+		 * The second character must be an asterisk.
+		 * If it isn't, skip it anyway:  It is escaped,
+		 * so it can't start another escape sequence.
+		 */
+
+		if ('\0' == *cp)
+			return(ROFF_CONT);
+
+		if ('*' != *cp) {
+			res = cp;
+			esc = mandoc_escape(&cp, NULL, NULL);
+			if (ESCAPE_ERROR != esc)
+				continue;
+			cp = res;
+			mandoc_msg
+				(MANDOCERR_BADESCAPE, r->parse, 
+				 ln, (int)(stesc - *bufp), NULL);
+			return(ROFF_CONT);
+		}
+
+		cp++;
+
+		/*
+		 * The third character decides the length
+		 * of the name of the string.
+		 * Save a pointer to the name.
+		 */
+
+		switch (*cp) {
+		case ('\0'):
+			return(ROFF_CONT);
+		case ('('):
+			cp++;
+			maxl = 2;
+			break;
+		case ('['):
+			cp++;
+			maxl = 0;
+			break;
+		default:
+			maxl = 1;
+			break;
+		}
+		stnam = cp;
+
+		/* Advance to the end of the name. */
+
+		for (i = 0; 0 == maxl || i < maxl; i++, cp++) {
+			if ('\0' == *cp) {
+				mandoc_msg
+					(MANDOCERR_BADESCAPE, 
+					 r->parse, ln, 
+					 (int)(stesc - *bufp), NULL);
+				return(ROFF_CONT);
+			}
+			if (0 == maxl && ']' == *cp)
+				break;
+		}
+
+		/*
+		 * Retrieve the replacement string; if it is
+		 * undefined, resume searching for escapes.
+		 */
+
+		res = roff_getstrn(r, stnam, (size_t)i);
+
+		if (NULL == res) {
+			mandoc_msg
+				(MANDOCERR_BADESCAPE, r->parse, 
+				 ln, (int)(stesc - *bufp), NULL);
+			res = "";
+		}
+
+		/* Replace the escape sequence by the string. */
+
+		pos = stesc - *bufp;
+
+		nsz = *szp + strlen(res) + 1;
+		n = mandoc_malloc(nsz);
+
+		strlcpy(n, *bufp, (size_t)(stesc - *bufp + 1));
+		strlcat(n, res, nsz);
+		strlcat(n, cp + (maxl ? 0 : 1), nsz);
+
+		free(*bufp);
+
+		*bufp = n;
+		*szp = nsz;
+
+		if (EXPAND_LIMIT >= ++expand_count)
+			goto again;
+
+		/* Just leave the string unexpanded. */
+		mandoc_msg(MANDOCERR_ROFFLOOP, r->parse, ln, pos, NULL);
+		return(ROFF_IGN);
+	}
+	return(ROFF_CONT);
+}
+
+/*
+ * Process text streams: convert all breakable hyphens into ASCII_HYPH.
+ */
+static enum rofferr
+roff_parsetext(char *p)
+{
+	size_t		 sz;
+	const char	*start;
+	enum mandoc_esc	 esc;
+
+	start = p;
+
+	while ('\0' != *p) {
+		sz = strcspn(p, "-\\");
+		p += sz;
+
+		if ('\0' == *p)
+			break;
+
+		if ('\\' == *p) {
+			/* Skip over escapes. */
+			p++;
+			esc = mandoc_escape
+				((const char **)&p, NULL, NULL);
+			if (ESCAPE_ERROR == esc)
+				break;
+			continue;
+		} else if (p == start) {
+			p++;
+			continue;
+		}
+
+		if (isalpha((unsigned char)p[-1]) &&
+		    isalpha((unsigned char)p[1]))
+			*p = ASCII_HYPH;
+		p++;
+	}
+
+	return(ROFF_CONT);
+}
+
+enum rofferr
+roff_parseln(struct roff *r, int ln, char **bufp, 
+		size_t *szp, int pos, int *offs)
+{
+	enum rofft	 t;
+	enum rofferr	 e;
+	int		 ppos, ctl;
+
+	/*
+	 * Run the reserved-word filter only if we have some reserved
+	 * words to fill in.
+	 */
+
+	e = roff_res(r, bufp, szp, ln, pos);
+	if (ROFF_IGN == e)
+		return(e);
+	assert(ROFF_CONT == e);
+
+	ppos = pos;
+	ctl = mandoc_getcontrol(*bufp, &pos);
+
+	/*
+	 * First, if a scope is open and we're not a macro, pass the
+	 * text through the macro's filter.  If a scope isn't open and
+	 * we're not a macro, just let it through.
+	 * Finally, if there's an equation scope open, divert it into it
+	 * no matter our state.
+	 */
+
+	if (r->last && ! ctl) {
+		t = r->last->tok;
+		assert(roffs[t].text);
+		e = (*roffs[t].text)
+			(r, t, bufp, szp, ln, pos, pos, offs);
+		assert(ROFF_IGN == e || ROFF_CONT == e);
+		if (ROFF_CONT != e)
+			return(e);
+		if (r->eqn)
+			return(eqn_read(&r->eqn, ln, *bufp, pos, offs));
+		if (r->tbl)
+			return(tbl_read(r->tbl, ln, *bufp, pos));
+		return(roff_parsetext(*bufp + pos));
+	} else if ( ! ctl) {
+		if (r->eqn)
+			return(eqn_read(&r->eqn, ln, *bufp, pos, offs));
+		if (r->tbl)
+			return(tbl_read(r->tbl, ln, *bufp, pos));
+		return(roff_parsetext(*bufp + pos));
+	} else if (r->eqn)
+		return(eqn_read(&r->eqn, ln, *bufp, ppos, offs));
+
+	/*
+	 * If a scope is open, go to the child handler for that macro,
+	 * as it may want to preprocess before doing anything with it.
+	 * Don't do so if an equation is open.
+	 */
+
+	if (r->last) {
+		t = r->last->tok;
+		assert(roffs[t].sub);
+		return((*roffs[t].sub)
+				(r, t, bufp, szp, 
+				 ln, ppos, pos, offs));
+	}
+
+	/*
+	 * Lastly, as we've no scope open, try to look up and execute
+	 * the new macro.  If no macro is found, simply return and let
+	 * the compilers handle it.
+	 */
+
+	if (ROFF_MAX == (t = roff_parse(r, *bufp, &pos)))
+		return(ROFF_CONT);
+
+	assert(roffs[t].proc);
+	return((*roffs[t].proc)
+			(r, t, bufp, szp, 
+			 ln, ppos, pos, offs));
+}
+
+
+void
+roff_endparse(struct roff *r)
+{
+
+	if (r->last)
+		mandoc_msg(MANDOCERR_SCOPEEXIT, r->parse,
+				r->last->line, r->last->col, NULL);
+
+	if (r->eqn) {
+		mandoc_msg(MANDOCERR_SCOPEEXIT, r->parse, 
+				r->eqn->eqn.ln, r->eqn->eqn.pos, NULL);
+		eqn_end(&r->eqn);
+	}
+
+	if (r->tbl) {
+		mandoc_msg(MANDOCERR_SCOPEEXIT, r->parse, 
+				r->tbl->line, r->tbl->pos, NULL);
+		tbl_end(&r->tbl);
+	}
+}
+
+/*
+ * Parse a roff node's type from the input buffer.  This must be in the
+ * form of ".foo xxx" in the usual way.
+ */
+static enum rofft
+roff_parse(struct roff *r, const char *buf, int *pos)
+{
+	const char	*mac;
+	size_t		 maclen;
+	enum rofft	 t;
+
+	if ('\0' == buf[*pos] || '"' == buf[*pos] || 
+			'\t' == buf[*pos] || ' ' == buf[*pos])
+		return(ROFF_MAX);
+
+	/*
+	 * We stop the macro parse at an escape, tab, space, or nil.
+	 * However, `\}' is also a valid macro, so make sure we don't
+	 * clobber it by seeing the `\' as the end of token.
+	 */
+
+	mac = buf + *pos;
+	maclen = strcspn(mac + 1, " \\\t\0") + 1;
+
+	t = (r->current_string = roff_getstrn(r, mac, maclen))
+	    ? ROFF_USERDEF : roffhash_find(mac, maclen);
+
+	*pos += (int)maclen;
+
+	while (buf[*pos] && ' ' == buf[*pos])
+		(*pos)++;
+
+	return(t);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_cblock(ROFF_ARGS)
+{
+
+	/*
+	 * A block-close `..' should only be invoked as a child of an
+	 * ignore macro, otherwise raise a warning and just ignore it.
+	 */
+
+	if (NULL == r->last) {
+		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+		return(ROFF_IGN);
+	}
+
+	switch (r->last->tok) {
+	case (ROFF_am):
+		/* FALLTHROUGH */
+	case (ROFF_ami):
+		/* FALLTHROUGH */
+	case (ROFF_am1):
+		/* FALLTHROUGH */
+	case (ROFF_de):
+		/* ROFF_de1 is remapped to ROFF_de in roff_block(). */
+		/* FALLTHROUGH */
+	case (ROFF_dei):
+		/* FALLTHROUGH */
+	case (ROFF_ig):
+		break;
+	default:
+		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+		return(ROFF_IGN);
+	}
+
+	if ((*bufp)[pos])
+		mandoc_msg(MANDOCERR_ARGSLOST, r->parse, ln, pos, NULL);
+
+	roffnode_pop(r);
+	roffnode_cleanscope(r);
+	return(ROFF_IGN);
+
+}
+
+
+static void
+roffnode_cleanscope(struct roff *r)
+{
+
+	while (r->last) {
+		if (--r->last->endspan < 0)
+			break;
+		roffnode_pop(r);
+	}
+}
+
+
+/* ARGSUSED */
+static enum rofferr
+roff_ccond(ROFF_ARGS)
+{
+
+	if (NULL == r->last) {
+		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+		return(ROFF_IGN);
+	}
+
+	switch (r->last->tok) {
+	case (ROFF_el):
+		/* FALLTHROUGH */
+	case (ROFF_ie):
+		/* FALLTHROUGH */
+	case (ROFF_if):
+		break;
+	default:
+		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+		return(ROFF_IGN);
+	}
+
+	if (r->last->endspan > -1) {
+		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+		return(ROFF_IGN);
+	}
+
+	if ((*bufp)[pos])
+		mandoc_msg(MANDOCERR_ARGSLOST, r->parse, ln, pos, NULL);
+
+	roffnode_pop(r);
+	roffnode_cleanscope(r);
+	return(ROFF_IGN);
+}
+
+
+/* ARGSUSED */
+static enum rofferr
+roff_block(ROFF_ARGS)
+{
+	int		sv;
+	size_t		sz;
+	char		*name;
+
+	name = NULL;
+
+	if (ROFF_ig != tok) {
+		if ('\0' == (*bufp)[pos]) {
+			mandoc_msg(MANDOCERR_NOARGS, r->parse, ln, ppos, NULL);
+			return(ROFF_IGN);
+		}
+
+		/*
+		 * Re-write `de1', since we don't really care about
+		 * groff's strange compatibility mode, into `de'.
+		 */
+
+		if (ROFF_de1 == tok)
+			tok = ROFF_de;
+		if (ROFF_de == tok)
+			name = *bufp + pos;
+		else
+			mandoc_msg(MANDOCERR_REQUEST, r->parse, ln, ppos,
+			    roffs[tok].name);
+
+		while ((*bufp)[pos] && ! isspace((unsigned char)(*bufp)[pos]))
+			pos++;
+
+		while (isspace((unsigned char)(*bufp)[pos]))
+			(*bufp)[pos++] = '\0';
+	}
+
+	roffnode_push(r, tok, name, ln, ppos);
+
+	/*
+	 * At the beginning of a `de' macro, clear the existing string
+	 * with the same name, if there is one.  New content will be
+	 * added from roff_block_text() in multiline mode.
+	 */
+
+	if (ROFF_de == tok)
+		roff_setstr(r, name, "", 0);
+
+	if ('\0' == (*bufp)[pos])
+		return(ROFF_IGN);
+
+	/* If present, process the custom end-of-line marker. */
+
+	sv = pos;
+	while ((*bufp)[pos] && ! isspace((unsigned char)(*bufp)[pos]))
+		pos++;
+
+	/*
+	 * Note: groff does NOT like escape characters in the input.
+	 * Instead of detecting this, we're just going to let it fly and
+	 * to hell with it.
+	 */
+
+	assert(pos > sv);
+	sz = (size_t)(pos - sv);
+
+	if (1 == sz && '.' == (*bufp)[sv])
+		return(ROFF_IGN);
+
+	r->last->end = mandoc_malloc(sz + 1);
+
+	memcpy(r->last->end, *bufp + sv, sz);
+	r->last->end[(int)sz] = '\0';
+
+	if ((*bufp)[pos])
+		mandoc_msg(MANDOCERR_ARGSLOST, r->parse, ln, pos, NULL);
+
+	return(ROFF_IGN);
+}
+
+
+/* ARGSUSED */
+static enum rofferr
+roff_block_sub(ROFF_ARGS)
+{
+	enum rofft	t;
+	int		i, j;
+
+	/*
+	 * First check whether a custom macro exists at this level.  If
+	 * it does, then check against it.  This is some of groff's
+	 * stranger behaviours.  If we encountered a custom end-scope
+	 * tag and that tag also happens to be a "real" macro, then we
+	 * need to try interpreting it again as a real macro.  If it's
+	 * not, then return ignore.  Else continue.
+	 */
+
+	if (r->last->end) {
+		for (i = pos, j = 0; r->last->end[j]; j++, i++)
+			if ((*bufp)[i] != r->last->end[j])
+				break;
+
+		if ('\0' == r->last->end[j] && 
+				('\0' == (*bufp)[i] ||
+				 ' ' == (*bufp)[i] ||
+				 '\t' == (*bufp)[i])) {
+			roffnode_pop(r);
+			roffnode_cleanscope(r);
+
+			while (' ' == (*bufp)[i] || '\t' == (*bufp)[i])
+				i++;
+
+			pos = i;
+			if (ROFF_MAX != roff_parse(r, *bufp, &pos))
+				return(ROFF_RERUN);
+			return(ROFF_IGN);
+		}
+	}
+
+	/*
+	 * If we have no custom end-query or lookup failed, then try
+	 * pulling it out of the hashtable.
+	 */
+
+	t = roff_parse(r, *bufp, &pos);
+
+	/*
+	 * Macros other than block-end are only significant
+	 * in `de' blocks; elsewhere, simply throw them away.
+	 */
+	if (ROFF_cblock != t) {
+		if (ROFF_de == tok)
+			roff_setstr(r, r->last->name, *bufp + ppos, 1);
+		return(ROFF_IGN);
+	}
+
+	assert(roffs[t].proc);
+	return((*roffs[t].proc)(r, t, bufp, szp, 
+				ln, ppos, pos, offs));
+}
+
+
+/* ARGSUSED */
+static enum rofferr
+roff_block_text(ROFF_ARGS)
+{
+
+	if (ROFF_de == tok)
+		roff_setstr(r, r->last->name, *bufp + pos, 1);
+
+	return(ROFF_IGN);
+}
+
+
+/* ARGSUSED */
+static enum rofferr
+roff_cond_sub(ROFF_ARGS)
+{
+	enum rofft	 t;
+	enum roffrule	 rr;
+	char		*ep;
+
+	rr = r->last->rule;
+	roffnode_cleanscope(r);
+
+	/*
+	 * If the macro is unknown, first check if it contains a closing
+	 * delimiter `\}'.  If it does, close out our scope and return
+	 * the currently-scoped rule (ignore or continue).  Else, drop
+	 * into the currently-scoped rule.
+	 */
+
+	if (ROFF_MAX == (t = roff_parse(r, *bufp, &pos))) {
+		ep = &(*bufp)[pos];
+		for ( ; NULL != (ep = strchr(ep, '\\')); ep++) {
+			ep++;
+			if ('}' != *ep)
+				continue;
+
+			/*
+			 * Make the \} go away.
+			 * This is a little haphazard, as it's not quite
+			 * clear how nroff does this.
+			 * If we're at the end of line, then just chop
+			 * off the \} and resize the buffer.
+			 * If we aren't, then conver it to spaces.
+			 */
+
+			if ('\0' == *(ep + 1)) {
+				*--ep = '\0';
+				*szp -= 2;
+			} else
+				*(ep - 1) = *ep = ' ';
+
+			roff_ccond(r, ROFF_ccond, bufp, szp, 
+					ln, pos, pos + 2, offs);
+			break;
+		}
+		return(ROFFRULE_DENY == rr ? ROFF_IGN : ROFF_CONT);
+	}
+
+	/*
+	 * A denied conditional must evaluate its children if and only
+	 * if they're either structurally required (such as loops and
+	 * conditionals) or a closing macro.
+	 */
+
+	if (ROFFRULE_DENY == rr)
+		if ( ! (ROFFMAC_STRUCT & roffs[t].flags))
+			if (ROFF_ccond != t)
+				return(ROFF_IGN);
+
+	assert(roffs[t].proc);
+	return((*roffs[t].proc)(r, t, bufp, szp, 
+				ln, ppos, pos, offs));
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_cond_text(ROFF_ARGS)
+{
+	char		*ep;
+	enum roffrule	 rr;
+
+	rr = r->last->rule;
+	roffnode_cleanscope(r);
+
+	ep = &(*bufp)[pos];
+	for ( ; NULL != (ep = strchr(ep, '\\')); ep++) {
+		ep++;
+		if ('}' != *ep)
+			continue;
+		*ep = '&';
+		roff_ccond(r, ROFF_ccond, bufp, szp, 
+				ln, pos, pos + 2, offs);
+	}
+	return(ROFFRULE_DENY == rr ? ROFF_IGN : ROFF_CONT);
+}
+
+static enum roffrule
+roff_evalcond(const char *v, int *pos)
+{
+
+	switch (v[*pos]) {
+	case ('n'):
+		(*pos)++;
+		return(ROFFRULE_ALLOW);
+	case ('e'):
+		/* FALLTHROUGH */
+	case ('o'):
+		/* FALLTHROUGH */
+	case ('t'):
+		(*pos)++;
+		return(ROFFRULE_DENY);
+	default:
+		break;
+	}
+
+	while (v[*pos] && ' ' != v[*pos])
+		(*pos)++;
+	return(ROFFRULE_DENY);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_line_ignore(ROFF_ARGS)
+{
+
+	if (ROFF_it == tok)
+		mandoc_msg(MANDOCERR_REQUEST, r->parse, ln, ppos, "it");
+
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_cond(ROFF_ARGS)
+{
+	int		 sv;
+	enum roffrule	 rule;
+
+	/* 
+	 * An `.el' has no conditional body: it will consume the value
+	 * of the current rstack entry set in prior `ie' calls or
+	 * defaults to DENY.  
+	 *
+	 * If we're not an `el', however, then evaluate the conditional.
+	 */
+
+	rule = ROFF_el == tok ?
+		(r->rstackpos < 0 ? 
+		 ROFFRULE_DENY : r->rstack[r->rstackpos--]) :
+		roff_evalcond(*bufp, &pos);
+
+	sv = pos;
+	while (' ' == (*bufp)[pos])
+		pos++;
+
+	/*
+	 * Roff is weird.  If we have just white-space after the
+	 * conditional, it's considered the BODY and we exit without
+	 * really doing anything.  Warn about this.  It's probably
+	 * wrong.
+	 */
+
+	if ('\0' == (*bufp)[pos] && sv != pos) {
+		mandoc_msg(MANDOCERR_NOARGS, r->parse, ln, ppos, NULL);
+		return(ROFF_IGN);
+	}
+
+	roffnode_push(r, tok, NULL, ln, ppos);
+
+	r->last->rule = rule;
+
+	/*
+	 * An if-else will put the NEGATION of the current evaluated
+	 * conditional into the stack of rules.
+	 */
+
+	if (ROFF_ie == tok) {
+		if (r->rstackpos == RSTACK_MAX - 1) {
+			mandoc_msg(MANDOCERR_MEM, 
+				r->parse, ln, ppos, NULL);
+			return(ROFF_ERR);
+		}
+		r->rstack[++r->rstackpos] = 
+			ROFFRULE_DENY == r->last->rule ?
+			ROFFRULE_ALLOW : ROFFRULE_DENY;
+	}
+
+	/* If the parent has false as its rule, then so do we. */
+
+	if (r->last->parent && ROFFRULE_DENY == r->last->parent->rule)
+		r->last->rule = ROFFRULE_DENY;
+
+	/*
+	 * Determine scope.  If we're invoked with "\{" trailing the
+	 * conditional, then we're in a multiline scope.  Else our scope
+	 * expires on the next line.
+	 */
+
+	r->last->endspan = 1;
+
+	if ('\\' == (*bufp)[pos] && '{' == (*bufp)[pos + 1]) {
+		r->last->endspan = -1;
+		pos += 2;
+	} 
+
+	/*
+	 * If there are no arguments on the line, the next-line scope is
+	 * assumed.
+	 */
+
+	if ('\0' == (*bufp)[pos])
+		return(ROFF_IGN);
+
+	/* Otherwise re-run the roff parser after recalculating. */
+
+	*offs = pos;
+	return(ROFF_RERUN);
+}
+
+
+/* ARGSUSED */
+static enum rofferr
+roff_ds(ROFF_ARGS)
+{
+	char		*name, *string;
+
+	/*
+	 * A symbol is named by the first word following the macro
+	 * invocation up to a space.  Its value is anything after the
+	 * name's trailing whitespace and optional double-quote.  Thus,
+	 *
+	 *  [.ds foo "bar  "     ]
+	 *
+	 * will have `bar  "     ' as its value.
+	 */
+
+	string = *bufp + pos;
+	name = roff_getname(r, &string, ln, pos);
+	if ('\0' == *name)
+		return(ROFF_IGN);
+
+	/* Read past initial double-quote. */
+	if ('"' == *string)
+		string++;
+
+	/* The rest is the value. */
+	roff_setstr(r, name, string, 0);
+	return(ROFF_IGN);
+}
+
+int
+roff_regisset(const struct roff *r, enum regs reg)
+{
+
+	return(r->regs[(int)reg].set);
+}
+
+unsigned int
+roff_regget(const struct roff *r, enum regs reg)
+{
+
+	return(r->regs[(int)reg].u);
+}
+
+void
+roff_regunset(struct roff *r, enum regs reg)
+{
+
+	r->regs[(int)reg].set = 0;
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_nr(ROFF_ARGS)
+{
+	const char	*key;
+	char		*val;
+	int		 iv;
+
+	val = *bufp + pos;
+	key = roff_getname(r, &val, ln, pos);
+
+	if (0 == strcmp(key, "nS")) {
+		r->regs[(int)REG_nS].set = 1;
+		if ((iv = mandoc_strntoi(val, strlen(val), 10)) >= 0)
+			r->regs[(int)REG_nS].u = (unsigned)iv;
+		else
+			r->regs[(int)REG_nS].u = 0u;
+	}
+
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_rm(ROFF_ARGS)
+{
+	const char	 *name;
+	char		 *cp;
+
+	cp = *bufp + pos;
+	while ('\0' != *cp) {
+		name = roff_getname(r, &cp, ln, (int)(cp - *bufp));
+		if ('\0' != *name)
+			roff_setstr(r, name, NULL, 0);
+	}
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_TE(ROFF_ARGS)
+{
+
+	if (NULL == r->tbl)
+		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+	else
+		tbl_end(&r->tbl);
+
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_T_(ROFF_ARGS)
+{
+
+	if (NULL == r->tbl)
+		mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+	else
+		tbl_restart(ppos, ln, r->tbl);
+
+	return(ROFF_IGN);
+}
+
+#if 0
+static int
+roff_closeeqn(struct roff *r)
+{
+
+	return(r->eqn && ROFF_EQN == eqn_end(&r->eqn) ? 1 : 0);
+}
+#endif
+
+static void
+roff_openeqn(struct roff *r, const char *name, int line, 
+		int offs, const char *buf)
+{
+	struct eqn_node *e;
+	int		 poff;
+
+	assert(NULL == r->eqn);
+	e = eqn_alloc(name, offs, line, r->parse);
+
+	if (r->last_eqn)
+		r->last_eqn->next = e;
+	else
+		r->first_eqn = r->last_eqn = e;
+
+	r->eqn = r->last_eqn = e;
+
+	if (buf) {
+		poff = 0;
+		eqn_read(&r->eqn, line, buf, offs, &poff);
+	}
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_EQ(ROFF_ARGS)
+{
+
+	roff_openeqn(r, *bufp + pos, ln, ppos, NULL);
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_EN(ROFF_ARGS)
+{
+
+	mandoc_msg(MANDOCERR_NOSCOPE, r->parse, ln, ppos, NULL);
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_TS(ROFF_ARGS)
+{
+	struct tbl_node	*t;
+
+	if (r->tbl) {
+		mandoc_msg(MANDOCERR_SCOPEBROKEN, r->parse, ln, ppos, NULL);
+		tbl_end(&r->tbl);
+	}
+
+	t = tbl_alloc(ppos, ln, r->parse);
+
+	if (r->last_tbl)
+		r->last_tbl->next = t;
+	else
+		r->first_tbl = r->last_tbl = t;
+
+	r->tbl = r->last_tbl = t;
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_tr(ROFF_ARGS)
+{
+	const char	*p, *first, *second;
+	size_t		 fsz, ssz;
+	enum mandoc_esc	 esc;
+
+	p = *bufp + pos;
+
+	if ('\0' == *p) {
+		mandoc_msg(MANDOCERR_ARGCOUNT, r->parse, ln, ppos, NULL);
+		return(ROFF_IGN);
+	}
+
+	while ('\0' != *p) {
+		fsz = ssz = 1;
+
+		first = p++;
+		if ('\\' == *first) {
+			esc = mandoc_escape(&p, NULL, NULL);
+			if (ESCAPE_ERROR == esc) {
+				mandoc_msg
+					(MANDOCERR_BADESCAPE, r->parse, 
+					 ln, (int)(p - *bufp), NULL);
+				return(ROFF_IGN);
+			}
+			fsz = (size_t)(p - first);
+		}
+
+		second = p++;
+		if ('\\' == *second) {
+			esc = mandoc_escape(&p, NULL, NULL);
+			if (ESCAPE_ERROR == esc) {
+				mandoc_msg
+					(MANDOCERR_BADESCAPE, r->parse, 
+					 ln, (int)(p - *bufp), NULL);
+				return(ROFF_IGN);
+			}
+			ssz = (size_t)(p - second);
+		} else if ('\0' == *second) {
+			mandoc_msg(MANDOCERR_ARGCOUNT, r->parse, 
+					ln, (int)(p - *bufp), NULL);
+			second = " ";
+			p--;
+		}
+
+		if (fsz > 1) {
+			roff_setstrn(&r->xmbtab, first, 
+					fsz, second, ssz, 0);
+			continue;
+		}
+
+		if (NULL == r->xtab)
+			r->xtab = mandoc_calloc
+				(128, sizeof(struct roffstr));
+
+		free(r->xtab[(int)*first].p);
+		r->xtab[(int)*first].p = mandoc_strndup(second, ssz);
+		r->xtab[(int)*first].sz = ssz;
+	}
+
+	return(ROFF_IGN);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_so(ROFF_ARGS)
+{
+	char *name;
+
+	mandoc_msg(MANDOCERR_SO, r->parse, ln, ppos, NULL);
+
+	/*
+	 * Handle `so'.  Be EXTREMELY careful, as we shouldn't be
+	 * opening anything that's not in our cwd or anything beneath
+	 * it.  Thus, explicitly disallow traversing up the file-system
+	 * or using absolute paths.
+	 */
+
+	name = *bufp + pos;
+	if ('/' == *name || strstr(name, "../") || strstr(name, "/..")) {
+		mandoc_msg(MANDOCERR_SOPATH, r->parse, ln, pos, NULL);
+		return(ROFF_ERR);
+	}
+
+	*offs = pos;
+	return(ROFF_SO);
+}
+
+/* ARGSUSED */
+static enum rofferr
+roff_userdef(ROFF_ARGS)
+{
+	const char	 *arg[9];
+	char		 *cp, *n1, *n2;
+	int		  i;
+
+	/*
+	 * Collect pointers to macro argument strings
+	 * and null-terminate them.
+	 */
+	cp = *bufp + pos;
+	for (i = 0; i < 9; i++)
+		arg[i] = '\0' == *cp ? "" :
+		    mandoc_getarg(r->parse, &cp, ln, &pos);
+
+	/*
+	 * Expand macro arguments.
+	 */
+	*szp = 0;
+	n1 = cp = mandoc_strdup(r->current_string);
+	while (NULL != (cp = strstr(cp, "\\$"))) {
+		i = cp[2] - '1';
+		if (0 > i || 8 < i) {
+			/* Not an argument invocation. */
+			cp += 2;
+			continue;
+		}
+
+		*szp = strlen(n1) - 3 + strlen(arg[i]) + 1;
+		n2 = mandoc_malloc(*szp);
+
+		strlcpy(n2, n1, (size_t)(cp - n1 + 1));
+		strlcat(n2, arg[i], *szp);
+		strlcat(n2, cp + 3, *szp);
+
+		cp = n2 + (cp - n1);
+		free(n1);
+		n1 = n2;
+	}
+
+	/*
+	 * Replace the macro invocation
+	 * by the expanded macro.
+	 */
+	free(*bufp);
+	*bufp = n1;
+	if (0 == *szp)
+		*szp = strlen(*bufp) + 1;
+
+	return(*szp > 1 && '\n' == (*bufp)[(int)*szp - 2] ?
+	   ROFF_REPARSE : ROFF_APPEND);
+}
+
+static char *
+roff_getname(struct roff *r, char **cpp, int ln, int pos)
+{
+	char	 *name, *cp;
+
+	name = *cpp;
+	if ('\0' == *name)
+		return(name);
+
+	/* Read until end of name. */
+	for (cp = name; '\0' != *cp && ' ' != *cp; cp++) {
+		if ('\\' != *cp)
+			continue;
+		cp++;
+		if ('\\' == *cp)
+			continue;
+		mandoc_msg(MANDOCERR_NAMESC, r->parse, ln, pos, NULL);
+		*cp = '\0';
+		name = cp;
+	}
+
+	/* Nil-terminate name. */
+	if ('\0' != *cp)
+		*(cp++) = '\0';
+
+	/* Read past spaces. */
+	while (' ' == *cp)
+		cp++;
+
+	*cpp = cp;
+	return(name);
+}
+
+/*
+ * Store *string into the user-defined string called *name.
+ * In multiline mode, append to an existing entry and append '\n';
+ * else replace the existing entry, if there is one.
+ * To clear an existing entry, call with (*r, *name, NULL, 0).
+ */
+static void
+roff_setstr(struct roff *r, const char *name, const char *string,
+	int multiline)
+{
+
+	roff_setstrn(&r->strtab, name, strlen(name), string,
+			string ? strlen(string) : 0, multiline);
+}
+
+static void
+roff_setstrn(struct roffkv **r, const char *name, size_t namesz,
+		const char *string, size_t stringsz, int multiline)
+{
+	struct roffkv	*n;
+	char		*c;
+	int		 i;
+	size_t		 oldch, newch;
+
+	/* Search for an existing string with the same name. */
+	n = *r;
+
+	while (n && strcmp(name, n->key.p))
+		n = n->next;
+
+	if (NULL == n) {
+		/* Create a new string table entry. */
+		n = mandoc_malloc(sizeof(struct roffkv));
+		n->key.p = mandoc_strndup(name, namesz);
+		n->key.sz = namesz;
+		n->val.p = NULL;
+		n->val.sz = 0;
+		n->next = *r;
+		*r = n;
+	} else if (0 == multiline) {
+		/* In multiline mode, append; else replace. */
+		free(n->val.p);
+		n->val.p = NULL;
+		n->val.sz = 0;
+	}
+
+	if (NULL == string)
+		return;
+
+	/*
+	 * One additional byte for the '\n' in multiline mode,
+	 * and one for the terminating '\0'.
+	 */
+	newch = stringsz + (multiline ? 2u : 1u);
+
+	if (NULL == n->val.p) {
+		n->val.p = mandoc_malloc(newch);
+		*n->val.p = '\0';
+		oldch = 0;
+	} else {
+		oldch = n->val.sz;
+		n->val.p = mandoc_realloc(n->val.p, oldch + newch);
+	}
+
+	/* Skip existing content in the destination buffer. */
+	c = n->val.p + (int)oldch;
+
+	/* Append new content to the destination buffer. */
+	i = 0;
+	while (i < (int)stringsz) {
+		/*
+		 * Rudimentary roff copy mode:
+		 * Handle escaped backslashes.
+		 */
+		if ('\\' == string[i] && '\\' == string[i + 1])
+			i++;
+		*c++ = string[i++];
+	}
+
+	/* Append terminating bytes. */
+	if (multiline)
+		*c++ = '\n';
+
+	*c = '\0';
+	n->val.sz = (int)(c - n->val.p);
+}
+
+static const char *
+roff_getstrn(const struct roff *r, const char *name, size_t len)
+{
+	const struct roffkv *n;
+
+	for (n = r->strtab; n; n = n->next)
+		if (0 == strncmp(name, n->key.p, len) && 
+				'\0' == n->key.p[(int)len])
+			return(n->val.p);
+
+	return(NULL);
+}
+
+static void
+roff_freestr(struct roffkv *r)
+{
+	struct roffkv	 *n, *nn;
+
+	for (n = r; n; n = nn) {
+		free(n->key.p);
+		free(n->val.p);
+		nn = n->next;
+		free(n);
+	}
+}
+
+const struct tbl_span *
+roff_span(const struct roff *r)
+{
+	
+	return(r->tbl ? tbl_span(r->tbl) : NULL);
+}
+
+const struct eqn *
+roff_eqn(const struct roff *r)
+{
+	
+	return(r->last_eqn ? &r->last_eqn->eqn : NULL);
+}
+
+/*
+ * Duplicate an input string, making the appropriate character
+ * conversations (as stipulated by `tr') along the way.
+ * Returns a heap-allocated string with all the replacements made.
+ */
+char *
+roff_strdup(const struct roff *r, const char *p)
+{
+	const struct roffkv *cp;
+	char		*res;
+	const char	*pp;
+	size_t		 ssz, sz;
+	enum mandoc_esc	 esc;
+
+	if (NULL == r->xmbtab && NULL == r->xtab)
+		return(mandoc_strdup(p));
+	else if ('\0' == *p)
+		return(mandoc_strdup(""));
+
+	/*
+	 * Step through each character looking for term matches
+	 * (remember that a `tr' can be invoked with an escape, which is
+	 * a glyph but the escape is multi-character).
+	 * We only do this if the character hash has been initialised
+	 * and the string is >0 length.
+	 */
+
+	res = NULL;
+	ssz = 0;
+
+	while ('\0' != *p) {
+		if ('\\' != *p && r->xtab && r->xtab[(int)*p].p) {
+			sz = r->xtab[(int)*p].sz;
+			res = mandoc_realloc(res, ssz + sz + 1);
+			memcpy(res + ssz, r->xtab[(int)*p].p, sz);
+			ssz += sz;
+			p++;
+			continue;
+		} else if ('\\' != *p) {
+			res = mandoc_realloc(res, ssz + 2);
+			res[ssz++] = *p++;
+			continue;
+		}
+
+		/* Search for term matches. */
+		for (cp = r->xmbtab; cp; cp = cp->next)
+			if (0 == strncmp(p, cp->key.p, cp->key.sz))
+				break;
+
+		if (NULL != cp) {
+			/*
+			 * A match has been found.
+			 * Append the match to the array and move
+			 * forward by its keysize.
+			 */
+			res = mandoc_realloc
+				(res, ssz + cp->val.sz + 1);
+			memcpy(res + ssz, cp->val.p, cp->val.sz);
+			ssz += cp->val.sz;
+			p += (int)cp->key.sz;
+			continue;
+		}
+
+		/*
+		 * Handle escapes carefully: we need to copy
+		 * over just the escape itself, or else we might
+		 * do replacements within the escape itself.
+		 * Make sure to pass along the bogus string.
+		 */
+		pp = p++;
+		esc = mandoc_escape(&p, NULL, NULL);
+		if (ESCAPE_ERROR == esc) {
+			sz = strlen(pp);
+			res = mandoc_realloc(res, ssz + sz + 1);
+			memcpy(res + ssz, pp, sz);
+			break;
+		}
+		/* 
+		 * We bail out on bad escapes. 
+		 * No need to warn: we already did so when
+		 * roff_res() was called.
+		 */
+		sz = (int)(p - pp);
+		res = mandoc_realloc(res, ssz + sz + 1);
+		memcpy(res + ssz, pp, sz);
+		ssz += sz;
+	}
+
+	res[(int)ssz] = '\0';
+	return(res);
+}