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

 (fun foo -> float4
  [] 
  (return (float4 1 1 1 1)))

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