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// run-pass
#![feature(box_patterns)]
#[derive(Clone)]
enum Noun
{
Atom(isize),
Cell(Box<Noun>, Box<Noun>)
}
fn fas(n: &Noun) -> Noun
{
match n {
&Noun::Cell(box Noun::Atom(2), box Noun::Cell(ref a, _)) => (**a).clone(),
_ => panic!("Invalid fas pattern")
}
}
pub fn main() {
fas(
&Noun::Cell(Box::new(Noun::Atom(2)),
Box::new(Noun::Cell(Box::new(Noun::Atom(2)), Box::new(Noun::Atom(3)))))
);
}
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