===================================================================
RCS file: /cvs/mandoc/mandoc.h,v
retrieving revision 1.80
retrieving revision 1.87
diff -u -p -r1.80 -r1.87
--- mandoc/mandoc.h	2011/07/17 14:08:49	1.80
+++ mandoc/mandoc.h	2011/07/21 14:13:00	1.87
@@ -1,4 +1,4 @@
-/*	$Id: mandoc.h,v 1.80 2011/07/17 14:08:49 kristaps Exp $ */
+/*	$Id: mandoc.h,v 1.87 2011/07/21 14:13:00 kristaps Exp $ */
 /*
  * Copyright (c) 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
  *
@@ -111,6 +111,9 @@ enum	mandocerr {
 
 	/* related to equations */
 	MANDOCERR_EQNARGS, /* bad equation macro arguments */
+	MANDOCERR_EQNNEST, /* too many nested equation defines */
+	MANDOCERR_EQNNSCOPE, /* unexpected equation scope closure*/
+	MANDOCERR_EQNSCOPE, /* equation scope open on exit */
 
 	/* related to tables */
 	MANDOCERR_TBL, /* bad table syntax */
@@ -276,10 +279,65 @@ struct	tbl_span {
 	struct tbl_span	 *next;
 };
 
+enum	eqn_boxt {
+	EQN_ROOT, /* root of parse tree */
+	EQN_TEXT, /* text (number, variable, whatever) */
+	EQN_SUBEXPR /* nested subexpression */
+};
+
+enum	eqn_markt {
+	EQNMARK_NONE = 0,
+	EQNMARK_DOT,
+	EQNMARK_DOTDOT,
+	EQNMARK_HAT,
+	EQNMARK_TILDE,
+	EQNMARK_VEC,
+	EQNMARK_DYAD,
+	EQNMARK_BAR,
+	EQNMARK_UNDER,
+	EQNMARK__MAX
+};
+
+enum	eqn_fontt {
+	EQNFONT_NONE = 0,
+	EQNFONT_ROMAN,
+	EQNFONT_BOLD,
+	EQNFONT_ITALIC,
+	EQNFONT__MAX
+};
+
+enum	eqn_post {
+	EQNPOS_NONE = 0,
+	EQNPOS_OVER,
+	EQNPOS_SUP,
+	EQNPOS_SUB,
+	EQNPOS_TO,
+	EQNPOS_FROM,
+	EQNPOS_ABOVE,
+	EQNPOS__MAX
+};
+
+ /*
+ * A "box" is a parsed mathematical expression as defined by the eqn.7
+ * grammar.
+ */
+struct	eqn_box {
+	enum eqn_boxt	  type; /* type of node */
+	struct eqn_box	 *child; /* child node */
+	struct eqn_box	 *next; /* next in tree */
+	enum eqn_post	  pos; /* position of next box */
+	char		 *text; /* text (or NULL) */
+	enum eqn_markt	  mark; /* a mark about the box */
+	enum eqn_fontt	  font; /* font of box */
+};
+
+/*
+ * An equation consists of a tree of expressions starting at a given
+ * line and position. 
+ */
 struct	eqn {
-	size_t		  sz;
-	char		 *data;
-	int		  line; /* invocation line */
+	struct eqn_box	 *root; /* root mathematical expression */
+	int		  ln; /* invocation line */
 	int		  pos; /* invocation position */
 };