Life of a tree

main.rs

#[derive(Debug)]
enum Tree {
    Seed,
    Sprout,
    Seedling,
    Sapling,
    Mature,
    Decline,
    Snag,
}

fn unbox<T>(value: Box<T>) -> T {
    *value
}

impl From<Box<Tree>> for Tree {
    fn from(t: Box<Self>) -> Self {
        let next = match *t {
            Self::Seed => Self::Sprout,
            Self::Sprout => Self::Seedling,
            Self::Seedling => Self::Sapling,
            Self::Sapling => Self::Mature,
            Self::Mature => Self::Decline,
            Self::Decline => Self::Snag,
            t => t,
        };
        next
    }
}

fn tree_life() {
    let mut tree = Box::new(Tree::Seed);
    loop {
        tree = Box::new(tree.into());
        println!("Tree is now a {:?}", tree);
        if let Tree::Snag = *tree {
            break;
        }
    }
}

fn main() {
  tree_life();
}