include "std/prelude.moc"

// Predeclare a type by giving its name, generics followed by a `:`
struct Tree:
// pre-declared types allow for self-referential types.
struct Tree {
    pub u64: value
    pub Vec<Tree>: leaves   
}

fn new_leaf(u64) -> [Tree] {
    Vec.new::<Tree> cast(Tree)
}

fn add_leaf(Tree: leaf Tree: mut self) -> [Tree] {
    leaf *self::leaves Vec.push
    self
}

fn Tree.print(u64: level &Tree: self) {

    0 while dup level < do {
        as [i]
        '\t' print
        i 1 + 
    } drop

    self::value @ println

    0 while dup self::leaves Vec.len < do {
        as [i]
        level 1 + i self::leaves Vec.get Option.unwrap Tree.print
        i 1 +
    } drop
}

fn main() {
    
    1 new_leaf
    2 new_leaf
    3 new_leaf add_leaf add_leaf
    4 new_leaf
    5 new_leaf
    6 new_leaf add_leaf add_leaf
    7 new_leaf add_leaf add_leaf as [tree]

    0 &tree Tree.print


}