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.

6 files changed, 101 insertions, 87 deletions

diff --git a/TODO b/TODO
index d077ef26..4af9d6d9 100644
--- a/TODO
+++ b/TODO
@@ -224,9 +224,6 @@ are mere guesses, and some may be wrong.
 
 --- missing eqn features -----------------------------------------------
 
-- delim
-  loc **  exist **  algo **  size *  imp ***
-
 - The "size" keyword is parsed, but ignored by the formatter.
   loc *  exist *  algo *  size *  imp *
 
@@ -515,6 +512,9 @@ are mere guesses, and some may be wrong.
 
 - mention /usr/share/misc/mdoc.template in mdoc(7)?
 
+- Is all the content from http://www.std.com/obi/BSD/doc/usd/28.tbl/tbl
+  covered in tbl(7)?
+
 ************************************************************************
 * performance issues
 ************************************************************************
diff --git a/eqn.c b/eqn.c
index 64f2348d..19bd6910 100644
--- a/eqn.c
+++ b/eqn.c
@@ -588,6 +588,30 @@ eqn_box_makebinary(struct eqn_node *ep,
 }
 
 /*
+ * 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
@@ -698,6 +722,8 @@ this_tok:
 			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,
diff --git a/libmandoc.h b/libmandoc.h
index 4b62b231..d74d1e20 100644
--- a/libmandoc.h
+++ b/libmandoc.h
@@ -78,12 +78,6 @@ char		*roff_strdup(const struct roff *, const char *);
 int		 roff_getcontrol(const struct roff *,
 			const char *, int *);
 int		 roff_getformat(const struct roff *);
-#if 0
-char		 roff_eqndelim(const struct roff *);
-void		 roff_openeqn(struct roff *, const char *,
-			int, int, const char *);
-int		 roff_closeeqn(struct roff *);
-#endif
 
 const struct tbl_span	*roff_span(const struct roff *);
 const struct eqn	*roff_eqn(const struct roff *);
diff --git a/libroff.h b/libroff.h
index 465d2da9..03619c82 100644
--- a/libroff.h
+++ b/libroff.h
@@ -1,6 +1,7 @@
 /*	$Id$ */
 /*
  * Copyright (c) 2009, 2010, 2011 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
@@ -43,16 +44,19 @@ struct	tbl_node {
 };
 
 struct	eqn_node {
-	struct eqn_def	 *defs;
-	size_t		  defsz;
-	char		 *data;
-	size_t		  rew;
-	size_t		  cur;
-	size_t		  sz;
-	int		  gsize;
-	struct eqn	  eqn;
-	struct mparse	 *parse;
-	struct eqn_node  *next;
+	struct eqn	  eqn;    /* syntax tree of this equation */
+	struct mparse	 *parse;  /* main parser, for error reporting */
+	struct eqn_node  *next;   /* singly linked list of equations */
+	struct eqn_def	 *defs;   /* array of definitions */
+	char		 *data;   /* source code of this equation */
+	size_t		  defsz;  /* number of definitions */
+	size_t		  sz;     /* length of the source code */
+	size_t		  cur;    /* parse point in the source code */
+	size_t		  rew;    /* beginning of the current token */
+	int		  gsize;  /* default point size */
+	int		  delim;  /* in-line delimiters enabled */
+	char		  odelim; /* in-line opening delimiter */
+	char		  cdelim; /* in-line closing delimiter */
 };
 
 struct	eqn_def {
diff --git a/mdoc.c b/mdoc.c
index 4d4f504e..c05834ae 100644
--- a/mdoc.c
+++ b/mdoc.c
@@ -91,9 +91,6 @@ static	struct mdoc_node *node_alloc(struct mdoc *, int, int,
 				enum mdoct, enum mdoc_type);
 static	int		  node_append(struct mdoc *,
 				struct mdoc_node *);
-#if 0
-static	int		  mdoc_preptext(struct mdoc *, int, char *, int);
-#endif
 static	int		  mdoc_ptext(struct mdoc *, int, char *, int);
 static	int		  mdoc_pmacro(struct mdoc *, int, char *, int);
 
@@ -609,60 +606,6 @@ mdoc_node_relink(struct mdoc *mdoc, struct mdoc_node *p)
 	return(node_append(mdoc, p));
 }
 
-#if 0
-/*
- * Pre-treat a text line.
- * Text lines can consist of equations, which must be handled apart from
- * the regular text.
- * Thus, use this function to step through a line checking if it has any
- * equations embedded in it.
- * This must handle multiple equations AND equations that do not end at
- * the end-of-line, i.e., will re-enter in the next roff parse.
- */
-static int
-mdoc_preptext(struct mdoc *mdoc, int line, char *buf, int offs)
-{
-	char		*start, *end;
-	char		 delim;
-
-	while ('\0' != buf[offs]) {
-		/* Mark starting position if eqn is set. */
-		start = NULL;
-		if ('\0' != (delim = roff_eqndelim(mdoc->roff)))
-			if (NULL != (start = strchr(buf + offs, delim)))
-				*start++ = '\0';
-
-		/* Parse text as normal. */
-		if ( ! mdoc_ptext(mdoc, line, buf, offs))
-			return(0);
-
-		/* Continue only if an equation exists. */
-		if (NULL == start)
-			break;
-
-		/* Read past the end of the equation. */
-		offs += start - (buf + offs);
-		assert(start == &buf[offs]);
-		if (NULL != (end = strchr(buf + offs, delim))) {
-			*end++ = '\0';
-			while (' ' == *end)
-				end++;
-		}
-
-		/* Parse the equation itself. */
-		roff_openeqn(mdoc->roff, NULL, line, offs, buf);
-
-		/* Process a finished equation? */
-		if (roff_closeeqn(mdoc->roff))
-			if ( ! mdoc_addeqn(mdoc, roff_eqn(mdoc->roff)))
-				return(0);
-		offs += (end - (buf + offs));
-	}
-
-	return(1);
-}
-#endif
-
 /*
  * Parse free-form text, that is, a line that does not begin with the
  * control character.
diff --git a/roff.c b/roff.c
index 4e5d5024..4bbb48e3 100644
--- a/roff.c
+++ b/roff.c
@@ -120,6 +120,7 @@ struct	roff {
 	struct eqn_node	*last_eqn; /* last equation parsed */
 	struct eqn_node	*first_eqn; /* first equation parsed */
 	struct eqn_node	*eqn; /* current equation being parsed */
+	int		 eqn_inline; /* current equation is inline */
 	int		 options; /* parse options */
 	int		 rstacksz; /* current size limit of rstack */
 	int		 rstackpos; /* position in rstack */
@@ -183,6 +184,8 @@ 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 rofferr	 roff_eqndelim(struct roff *,
+				char **, size_t *, int);
 static	int		 roff_evalcond(const char *, int *);
 static	int		 roff_evalnum(const char *, int *, int *, int);
 static	int		 roff_evalpar(const char *, int *, int *);
@@ -724,10 +727,17 @@ roff_parseln(struct roff *r, int ln, char **bufp,
 	enum rofferr	 e;
 	int		 ppos, ctl;
 
-	/*
-	 * Run the reserved-word filter only if we have some reserved
-	 * words to fill in.
-	 */
+	/* Handle in-line equation delimiters. */
+
+	if (r->last_eqn != NULL && r->last_eqn->delim &&
+	    (r->eqn == NULL || r->eqn_inline)) {
+		e = roff_eqndelim(r, bufp, szp, pos);
+		if (e == ROFF_REPARSE)
+			return(e);
+		assert(e == ROFF_CONT);
+	}
+
+	/* Expand some escape sequences. */
 
 	e = roff_res(r, bufp, szp, ln, pos);
 	if (ROFF_IGN == e)
@@ -1841,14 +1851,48 @@ roff_T_(ROFF_ARGS)
 	return(ROFF_IGN);
 }
 
-#if 0
-static int
-roff_closeeqn(struct roff *r)
+/*
+ * Handle in-line equation delimiters.
+ */
+static enum rofferr
+roff_eqndelim(struct roff *r, char **bufp, size_t *szp, int pos)
 {
+	char	*cp1, *cp2;
 
-	return(r->eqn && ROFF_EQN == eqn_end(&r->eqn) ? 1 : 0);
+	/*
+	 * Outside equations, look for an opening delimiter.
+	 * If we are inside an equation, we already know it is
+	 * in-line, or this function wouldn't have been called;
+	 * so look for a closing delimiter.
+	 */
+
+	cp1 = *bufp + pos;
+	cp2 = strchr(cp1, r->eqn == NULL ?
+	    r->last_eqn->odelim : r->last_eqn->cdelim);
+	if (cp2 == NULL)
+		return(ROFF_CONT);
+
+	/* Found a delimiter; get rid of surrounding blanks. */
+
+	cp1 = cp2++;
+	while (cp2[0] == ' ')
+		cp2++;
+	while (cp1[-1] == ' ')
+		cp1--;
+	*cp1 = '\0';
+
+	/* Replace the delimiter with an equation macro. */
+
+	*szp = mandoc_asprintf(&cp1, "%s\n.E%c\n\\&%s", *bufp,
+	    r->eqn == NULL ? 'Q' : 'N', cp2) + 1;
+	free(*bufp);
+	*bufp = cp1;
+
+	/* Toggle the in-line state of the eqn subsystem. */
+
+	r->eqn_inline = r->eqn == NULL;
+	return(ROFF_REPARSE);
 }
-#endif
 
 static void
 roff_openeqn(struct roff *r, const char *name, int line,
@@ -1860,9 +1904,12 @@ roff_openeqn(struct roff *r, const char *name, int line,
 	assert(NULL == r->eqn);
 	e = eqn_alloc(name, offs, line, r->parse);
 
-	if (r->last_eqn)
+	if (r->last_eqn) {
 		r->last_eqn->next = e;
-	else
+		e->delim = r->last_eqn->delim;
+		e->odelim = r->last_eqn->odelim;
+		e->cdelim = r->last_eqn->cdelim;
+	} else
 		r->first_eqn = r->last_eqn = e;
 
 	r->eqn = r->last_eqn = e;