lang: add some parser-internal operators

lang/include/ivy/lang/operator.h

@@ -77,7 +77,10 @@ enum ivy_operator_id {
 	IVY_OP_UNDERSTANDS,
 	IVY_OP_SELF_ACCESS,
 	IVY_OP_PKG_ACCESS,
+
+	/* these are not real operators, and are just used internally by the parser. */
 	IVY_OP_MSG,
+	IVY_OP_LEFT_PAREN,
 };
 
 struct ivy_operator {
@@ -90,5 +93,6 @@ struct ivy_operator {
 };
 
 IVY_API const struct ivy_operator *ivy_operator_get(unsigned int token);
+IVY_API const char *ivy_operator_id_to_string(enum ivy_operator_id op);
 
 #endif