use std::fmt::{self, Display};

#[derive(Debug, PartialEq, Clone)]
pub enum Value {
    Num(i32),
    Bool(bool),
    Sym(String),
    App(Box<Value>, Box<Value>),
    Lam(String, Box<Value>),
}

impl Display for Value {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Value::Num(i) => write!(f, "{}", i),
            Value::Bool(b) => write!(f, "{}", b),
            Value::Sym(s) => write!(f, "{}", s),
            Value::App(l, r) => write!(f, "({} {})", l, r),
            Value::Lam(var, body) => write!(f, "(lam {} {})", var, body),
        }
    }
}