function even(digit) {
  return parseInt(digit) % 2 === 0;
}
ometa Debugger {
  log_next       = &anything:t   {console.log(t)},
  status         = { console.log(this) }
}
ometa EvenOdd <: Debugger {

  even        = ^digit:d ?(even(d)),
  odd         = ^digit:d ?(!even(d)),
  digit :even = status apply(even),
  number      = <(digit(#even) digit(#odd))+ digit(#even)?
                | digit(#even)
                >:n -> parseInt(n)
}

EvenOdd.matchAll("452", "number")