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Diffstat (limited to 'dhall/src/semantics/core/visitor.rs')
-rw-r--r-- | dhall/src/semantics/core/visitor.rs | 167 |
1 files changed, 0 insertions, 167 deletions
diff --git a/dhall/src/semantics/core/visitor.rs b/dhall/src/semantics/core/visitor.rs deleted file mode 100644 index d1a85d8..0000000 --- a/dhall/src/semantics/core/visitor.rs +++ /dev/null @@ -1,167 +0,0 @@ -use std::iter::FromIterator; - -use crate::semantics::{Binder, BuiltinClosure, ValueKind}; -use crate::syntax::Label; - -/// A visitor trait that can be used to traverse `ValueKind`s. We need this pattern so that Rust lets -/// us have as much mutability as we can. See the equivalent file in `crate::syntax` for more -/// details. -pub(crate) trait ValueKindVisitor<'a, V1, V2>: Sized { - type Error; - - fn visit_val(&mut self, val: &'a V1) -> Result<V2, Self::Error>; - fn visit_binder( - mut self, - _label: &'a Binder, - ty: &'a V1, - val: &'a V1, - ) -> Result<(V2, V2), Self::Error> { - Ok((self.visit_val(ty)?, self.visit_val(val)?)) - } - fn visit_vec(&mut self, x: &'a [V1]) -> Result<Vec<V2>, Self::Error> { - x.iter().map(|e| self.visit_val(e)).collect() - } - fn visit_opt( - &mut self, - x: &'a Option<V1>, - ) -> Result<Option<V2>, Self::Error> { - Ok(match x { - Some(x) => Some(self.visit_val(x)?), - None => None, - }) - } - fn visit_map<T>( - &mut self, - x: impl IntoIterator<Item = (&'a Label, &'a V1)>, - ) -> Result<T, Self::Error> - where - V1: 'a, - T: FromIterator<(Label, V2)>, - { - x.into_iter() - .map(|(k, x)| Ok((k.clone(), self.visit_val(x)?))) - .collect() - } - fn visit_optmap<T>( - &mut self, - x: impl IntoIterator<Item = (&'a Label, &'a Option<V1>)>, - ) -> Result<T, Self::Error> - where - V1: 'a, - T: FromIterator<(Label, Option<V2>)>, - { - x.into_iter() - .map(|(k, x)| Ok((k.clone(), self.visit_opt(x)?))) - .collect() - } - - fn visit( - self, - input: &'a ValueKind<V1>, - ) -> Result<ValueKind<V2>, Self::Error> { - visit_ref(self, input) - } -} - -fn visit_ref<'a, Visitor, V1, V2>( - mut v: Visitor, - input: &'a ValueKind<V1>, -) -> Result<ValueKind<V2>, Visitor::Error> -where - Visitor: ValueKindVisitor<'a, V1, V2>, -{ - use ValueKind::*; - Ok(match input { - LamClosure { - binder, - annot, - closure, - } => LamClosure { - binder: binder.clone(), - annot: v.visit_val(annot)?, - closure: closure.clone(), - }, - PiClosure { - binder, - annot, - closure, - } => PiClosure { - binder: binder.clone(), - annot: v.visit_val(annot)?, - closure: closure.clone(), - }, - AppliedBuiltin(BuiltinClosure { - b, - args, - types, - env, - }) => AppliedBuiltin(BuiltinClosure { - b: *b, - args: v.visit_vec(args)?, - types: v.visit_vec(types)?, - env: env.clone(), - }), - Var(v) => Var(*v), - Const(k) => Const(*k), - BoolLit(b) => BoolLit(*b), - NaturalLit(n) => NaturalLit(*n), - IntegerLit(n) => IntegerLit(*n), - DoubleLit(n) => DoubleLit(*n), - EmptyOptionalLit(t) => EmptyOptionalLit(v.visit_val(t)?), - NEOptionalLit(x) => NEOptionalLit(v.visit_val(x)?), - EmptyListLit(t) => EmptyListLit(v.visit_val(t)?), - NEListLit(xs) => NEListLit(v.visit_vec(xs)?), - RecordType(kts) => RecordType(v.visit_map(kts)?), - RecordLit(kvs) => RecordLit(v.visit_map(kvs)?), - UnionType(kts) => UnionType(v.visit_optmap(kts)?), - UnionConstructor(l, kts, uniont) => UnionConstructor( - l.clone(), - v.visit_optmap(kts)?, - v.visit_val(uniont)?, - ), - UnionLit(l, x, kts, uniont, ctort) => UnionLit( - l.clone(), - v.visit_val(x)?, - v.visit_optmap(kts)?, - v.visit_val(uniont)?, - v.visit_val(ctort)?, - ), - TextLit(ts) => TextLit( - ts.iter() - .map(|t| t.traverse_ref(|e| v.visit_val(e))) - .collect::<Result<_, _>>()?, - ), - Equivalence(x, y) => Equivalence(v.visit_val(x)?, v.visit_val(y)?), - PartialExpr(e) => PartialExpr(e.traverse_ref(|e| v.visit_val(e))?), - Thunk(th) => Thunk(th.clone()), - }) -} - -pub struct TraverseRefWithBindersVisitor<F1, F2> { - pub visit_val: F1, - pub visit_under_binder: F2, -} - -impl<'a, V1, V2, Err, F1, F2> ValueKindVisitor<'a, V1, V2> - for TraverseRefWithBindersVisitor<F1, F2> -where - V1: 'a, - F1: FnMut(&'a V1) -> Result<V2, Err>, - F2: for<'b> FnOnce(&'a Binder, &'b V1, &'a V1) -> Result<V2, Err>, -{ - type Error = Err; - - fn visit_val(&mut self, val: &'a V1) -> Result<V2, Self::Error> { - (self.visit_val)(val) - } - fn visit_binder<'b>( - mut self, - label: &'a Binder, - ty: &'a V1, - val: &'a V1, - ) -> Result<(V2, V2), Self::Error> { - let val = (self.visit_under_binder)(label, ty, val)?; - let ty = (self.visit_val)(ty)?; - Ok((ty, val)) - } -} |