init commit

test/parse/struct_within_struct.golden

@@ -0,0 +1,12 @@
+(program	
+ (struct Foo
+  [(:= color float4)])
+
+ (struct Bar
+  [(:= t Foo)])
+
+ (fun vertex vs_main
+  [] 
+  (:= f Foo) 
+  (:= b Bar) 
+  (= b.t f)))