value::{ListCell, Primitive, SymbolId, SymbolTable},

    value::{ConsCell, Primitive, SymbolId, SymbolTable},

    pub srl_registers: [Option<Gc<'gc, ListCell<'gc>>>; 255],

    pub srl_registers: [Option<Gc<'gc, ConsCell<'gc>>>; 255],

    List(Gc<'gc, ListCell<'gc>>),

    List(Gc<'gc, ConsCell<'gc>>),

    List(FreeListCell<'a>),

    List(FreeConsCell<'a>),

pub struct FreeListCell<'a> {

pub struct FreeConsCell<'a> {

}
impl<'a> FreeListCell<'a> {
    /// Create an empty list cell (Scheme `'()`)
    pub const fn empty() -> Self {
        Self {
            car: None,
            cdr: None,
        }
    }

pub struct ListCell<'gc> {

pub struct ConsCell<'gc> {

impl<'gc> ListCell<'gc> {

impl ConsCell<'static> {

        }
    }
}
impl<'gc> ConsCell<'gc> {
    /// Checks if this cell represents an empty list.
    pub fn is_empty_list(&self) -> bool {
        self.car.is_none() && self.cdr.is_none()
    }
    /// Checks if this cell is a list
    pub fn is_list(&self) -> bool {
        if let Some(cdr) = self.cdr.as_ref() {
            matches!(cdr.as_ref(), Primitive::List(_))
        } else {
            // We are a list by virtue of resembling the empty list.
            // Technically we have 2 representations of "empty list"
            // - a cdr pointer of None (the pointed empty list)
            // - a ConsCell with both car and cdr set to None (the object empty list)
            true