Store recursive children in a list

A list of children provides the indirection a recursive class needs; each child needs no additional box. Save this module as forest.plenty:

pub class Node[T]:
    pub value: T
    pub children: list[Node[T]]

import forest

def main() -> Result[(), AllocError | IoError]:
    mut root = forest.Node[i64](1, [forest.Node[i64](2, []?)]?)
    root.children[0].value = 9
    print(root.value)?
    print(root.children[0].value)?
    Ok(())

1
9

An empty children list terminates the tree. For a single optional child, use a field such as next: Option[Box[Node]] and terminate it with Nothing.