== updG =====
updG =>> fG1.upd   (*  :  *)
  fG1.updo =>> updGo   (*  :  *)
== stepG =====
stepG =>> eG1_X.prep   (*  :  *)
  eG1_X.prepO =>> stepGo   (*  :  *)
JOIN_fG1_step.J =>> fG1.step   (*  :  *)
== init =====
init =>> fG1.init   (*  :  *)
== ctor =====
ctor =>> fG1.ctor   (*  :  *)
