(program	
 (fun vertex vs_main -> float3 (@position)
  [(:= pos float3 (@position))] 
  (return pos))

 (fun foo -> float2
  [] 
  (return (float2 1 1)))

 (fun pixel ps_main -> float4 (@target0)
  [] 
  (:= y float2 (foo)) 
  (:= color float4 (float4 y 1 1 1)) 
  (return color)))