diff --git a/samples/sample_ast_01.parcel b/samples/sample_ast_01.parcel
new file mode 100644
index 0000000..cd6d168
--- /dev/null
+++ b/samples/sample_ast_01.parcel
@@ -0,0 +1,3 @@
+
+<root> = <ref1>, "+", <ref2> | <ref1>, "-", <ref2>;
+