diff --git a/Parser/parser.h b/Parser/parser.h
new file mode 100644
index 0000000..16eee0e
--- /dev/null
+++ b/Parser/parser.h
@@ -0,0 +1,25 @@
+/* Parser interface */
+
+#define MAXSTACK 100
+
+typedef struct _stackentry {
+	int		 s_state;	/* State in current DFA */
+	dfa		*s_dfa;		/* Current DFA */
+	node		*s_parent;	/* Where to add next node */
+} stackentry;
+
+typedef struct _stack {
+	stackentry	*s_top;		/* Top entry */
+	stackentry	 s_base[MAXSTACK];/* Array of stack entries */
+					/* NB The stack grows down */
+} stack;
+
+typedef struct {
+	struct _stack	 p_stack;	/* Stack of parser states */
+	struct _grammar	*p_grammar;	/* Grammar to use */
+	struct _node	*p_tree;	/* Top of parse tree */
+} parser_state;
+
+parser_state *newparser PROTO((struct _grammar *g, int start));
+void delparser PROTO((parser_state *ps));
+int addtoken PROTO((parser_state *ps, int type, char *str));