use std::rc::Rc;

#[derive(Debug, debug2::Debug, PartialEq)]

crate enum Tree {
    Leaf(Literal),
    Define(String, Box<Tree>),
    If(Box<[Tree; 3]>),
    Lambda(Lambda),
    Branch(Vec<Tree>),
}

#[derive(Debug, debug2::Debug, PartialEq, Clone)]

crate struct Lambda(crate Rc<[String]>, crate Rc<[Tree]>);

#[derive(Debug, debug2::Debug, PartialEq)]

crate enum Literal {
    Sym(String),
    Num(f64),
    Bool(bool),
}