// common externs
extern void truncate(in bit<32> length);
extern void resubmit<T>(in T x);
extern void recirculate<T>(in T x);
enum CloneType { I2E, E2I }
extern void clone(in CloneType type, 
                  in bit<32> session);

// v1model pipeline elements
parser Parser<H, M>(
  packet_in pkt,
  out H hdr,
  inout M meta,
  inout standard_metadata_t std_meta
);
control VerifyChecksum<H, M>(
  inout H hdr,
  inout M meta
);
control Ingress<H, M>(
  inout H hdr,
  inout M meta,
  inout standard_metadata_t std_meta
);
control Egress<H, M>(
  inout H hdr,
  inout M meta,
  inout standard_metadata_t std_meta
);                      
control ComputeChecksum<H, M>(
  inout H hdr,
  inout M meta
);
control Deparser<H>(
  packet_out b, in H hdr
);

// v1model switch
package V1Switch<H, M>(
  Parser<H, M> p,
  VerifyChecksum<H, M> vr,
  Ingress<H, M> ig,
  Egress<H, M> eg,
  ComputeChecksum<H, M> ck,
  Deparser<H> d
);