It seems over-engineered to me. Why go through all the hustle of code generation? It can be solved with a simple “for loop”:

  func isOdd(n int) bool {
    var odd bool
    for i := 0; i < n; i++ {
      odd = !odd
    }
    return odd
  }

Playground link: https://go.dev/play/p/8TIfzGrdWDF

I did not profile this one yet. But my intuition, and my industry experience, tell me that this is fast.