init commit

test/parse/passthrough.golden

@@ -0,0 +1,8 @@
+(program	
+ (fun vertex vs_main -> float3 (@position)
+  [(:= pos float3 (@position))] 
+  (return pos))
+
+ (fun pixel ps_main -> float4 (@target0)
+  [] 
+  (return (float4 1 1 1 1))))