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f035d41b XL |
1 | //! Visitor helpers |
2 | ||
5869c6ff | 3 | use crate::{BoundVar, ControlFlow, DebruijnIndex, Interner, Visit, Visitor}; |
f9f354fc | 4 | |
f035d41b | 5 | /// Visitor extensions. |
f9f354fc | 6 | pub trait VisitExt<I: Interner>: Visit<I> { |
f035d41b | 7 | /// Check whether there are free (non-bound) variables. |
f9f354fc XL |
8 | fn has_free_vars(&self, interner: &I) -> bool { |
9 | self.visit_with( | |
10 | &mut FindFreeVarsVisitor { interner }, | |
11 | DebruijnIndex::INNERMOST, | |
12 | ) | |
5869c6ff | 13 | .is_break() |
f9f354fc XL |
14 | } |
15 | } | |
16 | ||
17 | impl<T, I: Interner> VisitExt<I> for T where T: Visit<I> {} | |
18 | ||
f9f354fc XL |
19 | struct FindFreeVarsVisitor<'i, I: Interner> { |
20 | interner: &'i I, | |
21 | } | |
22 | ||
23 | impl<'i, I: Interner> Visitor<'i, I> for FindFreeVarsVisitor<'i, I> { | |
5869c6ff | 24 | type BreakTy = (); |
f9f354fc | 25 | |
5869c6ff | 26 | fn as_dyn(&mut self) -> &mut dyn Visitor<'i, I, BreakTy = Self::BreakTy> { |
f9f354fc XL |
27 | self |
28 | } | |
29 | ||
30 | fn interner(&self) -> &'i I { | |
31 | self.interner | |
32 | } | |
33 | ||
f035d41b | 34 | fn visit_free_var( |
f9f354fc XL |
35 | &mut self, |
36 | _bound_var: BoundVar, | |
37 | _outer_binder: DebruijnIndex, | |
5869c6ff XL |
38 | ) -> ControlFlow<()> { |
39 | ControlFlow::BREAK | |
f9f354fc XL |
40 | } |
41 | } |