1pub use derive_refineable::Refineable;
 2
 3pub trait Refineable: Clone {
 4    type Refinement: Refineable<Refinement = Self::Refinement> + Default;
 5
 6    fn refine(&mut self, refinement: &Self::Refinement);
 7    fn refined(mut self, refinement: &Self::Refinement) -> Self
 8    where
 9        Self: Sized,
10    {
11        self.refine(refinement);
12        self
13    }
14    fn from_refinement(refinement: &Self::Refinement) -> Self
15    where
16        Self: Default + Sized,
17    {
18        Self::default().refined(refinement)
19    }
20}
21
22pub struct RefinementCascade<S: Refineable>(Vec<Option<S::Refinement>>);
23
24impl<S: Refineable + Default> Default for RefinementCascade<S> {
25    fn default() -> Self {
26        Self(vec![Some(Default::default())])
27    }
28}
29
30#[derive(Copy, Clone)]
31pub struct CascadeSlot(usize);
32
33impl<S: Refineable + Default> RefinementCascade<S> {
34    pub fn reserve(&mut self) -> CascadeSlot {
35        self.0.push(None);
36        return CascadeSlot(self.0.len() - 1);
37    }
38
39    pub fn base(&mut self) -> &mut S::Refinement {
40        self.0[0].as_mut().unwrap()
41    }
42
43    pub fn set(&mut self, slot: CascadeSlot, refinement: Option<S::Refinement>) {
44        self.0[slot.0] = refinement
45    }
46
47    pub fn merged(&self) -> S::Refinement {
48        let mut merged = self.0[0].clone().unwrap();
49        for refinement in self.0.iter().skip(1) {
50            if let Some(refinement) = refinement {
51                merged.refine(refinement);
52            }
53        }
54        merged
55    }
56}