[1] <CLOSXP> ()
  _formals [2] <LISTSXP> ()
    x [3] <SYMSXP: > ()
    y [4] <REALSXP[1]> ()
    ... [3]
  _body [5] <LANGSXP> ()
    ...
  _env [6] <ENVSXP: global> ()
