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//! Tests if a trivial functor, which's lifetime depends on the mapping function, works.
use std::rc::Rc;
use higher::{Functor, Bind};
use higher_free_macro::free;
#[derive(Clone)]
struct TrivWithLifetime<'a,A,B>{
next : Rc<dyn Fn(B)->A + 'a>,
}
impl<'a,A : 'a,B : 'a> Functor<'a,A> for TrivWithLifetime<'a,A,B> {
type Target<T> = TrivWithLifetime<'a,T,B>;
fn fmap<C, F>(self, f: F) -> Self::Target<C>
where
F: Fn(A) -> C + 'a {
TrivWithLifetime{ next : Rc::new(move |x| f((self.next)(x)))}
}
}
free!(<'a>, FreeTriv<'a,A,B>, TrivWithLifetime<'a,FreeTriv<'a,A,B>,B>);
#[test]
fn test_trivial_with_lifetime(){
let f = FreeTriv::lift_f(TrivWithLifetime{next : Rc::new(|x : i32| x.abs() as u32)});
let f = f.bind(|x| FreeTriv::Pure(x));
match f {
FreeTriv::Free(f) => {
let n = (f.next)(-4);
match n {
FreeTriv::Pure(v) => assert_eq!(v,4u32),
FreeTriv::Free(_) => unreachable!(),
}
},
_ => unreachable!()
}
}
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