Enum Rec
allehanda::recurse
pub enum Rec<T> { Done(T), Go(Box<Fn() -> Rec<T>>), }
Done(T)
Go(Box<Fn() -> Rec<T>>)
impl<T> Rec<T>
fn done(x: T) -> Rec<T>
fn go<F: 'static + Fn() -> Rec<T>>(f: F) -> Rec<T>
fn run(self) -> T