1 files changed, 0 insertions, 458 deletions
diff --git a/dhall_syntax/src/visitor.rs b/dhall_syntax/src/visitor.rs
deleted file mode 100644
index 20bfc72..0000000
--- a/dhall_syntax/src/visitor.rs
+++ /dev/null
@@ -1,458 +0,0 @@
-use std::collections::BTreeMap;
-
-use crate::*;
-
-/// A way too generic Visitor trait.
-pub trait GenericVisitor<Input, Return>: Sized {
-    fn visit(self, input: Input) -> Return;
-}
-
-/// A visitor trait that can be used to traverse `ExprF`s. We need this pattern
-/// so that Rust lets us have as much mutability as we can.
-/// For example, `traverse_embed` cannot be made using only `traverse_ref`, because
-/// `traverse_ref` takes a `FnMut` so we would need to pass multiple mutable
-/// reverences to this argument to `traverse_ref`. But Rust's ownership system
-/// is all about preventing exactly this ! So we have to be more clever.
-/// The visitor pattern allows us to have only one mutable thing the whole
-/// time: the visitor itself. The visitor can then carry around multiple closures
-/// or just one, and Rust is ok with either. See for example TraverseRefVisitor
-/// and TraverseEmbedVisitor.
-/// This is very generic. For a more legible trait, see ExprFInFallibleVisitor
-pub trait ExprFVeryGenericVisitor<'a, Ret, SE1, L1, E1>: Sized {
-    type Error;
-    type SE2;
-    type L2;
-    type E2;
-
-    fn visit_subexpr(
-        &mut self,
-        subexpr: &'a SE1,
-    ) -> Result<Self::SE2, Self::Error>;
-    fn visit_label(&mut self, label: &'a L1) -> Result<Self::L2, Self::Error>;
-
-    fn visit_binder(
-        self,
-        label: &'a L1,
-        subexpr: &'a SE1,
-    ) -> Result<(Self::L2, Self::SE2), Self::Error>;
-
-    fn visit_embed_squash(self, embed: &'a E1) -> Result<Ret, Self::Error>;
-
-    // Called with the result of the map, in the non-embed case.
-    // Useful to change the result type, and/or avoid some loss of info
-    fn visit_resulting_exprf(
-        result: ExprF<Self::SE2, Self::L2, Self::E2>,
-    ) -> Result<Ret, Self::Error>;
-}
-
-impl<'a, T, Ret, SE1, L1, E1>
-    GenericVisitor<&'a ExprF<SE1, L1, E1>, Result<Ret, T::Error>> for T
-where
-    L1: Ord,
-    T::L2: Ord,
-    T: ExprFVeryGenericVisitor<'a, Ret, SE1, L1, E1>,
-{
-    fn visit(self, input: &'a ExprF<SE1, L1, E1>) -> Result<Ret, T::Error> {
-        fn vec<'a, T, U, Err, F: FnMut(&'a T) -> Result<U, Err>>(
-            x: &'a [T],
-            f: F,
-        ) -> Result<Vec<U>, Err> {
-            x.iter().map(f).collect()
-        }
-        fn opt<'a, T, U, Err, F: FnOnce(&'a T) -> Result<U, Err>>(
-            x: &'a Option<T>,
-            f: F,
-        ) -> Result<Option<U>, Err> {
-            Ok(match x {
-                Some(x) => Some(f(x)?),
-                None => None,
-            })
-        }
-        fn btmap<'a, V, Ret, SE, L, E>(
-            x: &'a BTreeMap<L, SE>,
-            mut v: V,
-        ) -> Result<BTreeMap<V::L2, V::SE2>, V::Error>
-        where
-            L: Ord,
-            V::L2: Ord,
-            V: ExprFVeryGenericVisitor<'a, Ret, SE, L, E>,
-        {
-            x.iter()
-                .map(|(k, x)| Ok((v.visit_label(k)?, v.visit_subexpr(x)?)))
-                .collect()
-        }
-        fn btoptmap<'a, V, Ret, SE, L, E>(
-            x: &'a BTreeMap<L, Option<SE>>,
-            mut v: V,
-        ) -> Result<BTreeMap<V::L2, Option<V::SE2>>, V::Error>
-        where
-            L: Ord,
-            V::L2: Ord,
-            V: ExprFVeryGenericVisitor<'a, Ret, SE, L, E>,
-        {
-            x.iter()
-                .map(|(k, x)| {
-                    Ok((
-                        v.visit_label(k)?,
-                        match x {
-                            Some(x) => Some(v.visit_subexpr(x)?),
-                            None => None,
-                        },
-                    ))
-                })
-                .collect()
-        }
-
-        let mut v = self;
-        use crate::ExprF::*;
-        T::visit_resulting_exprf(match input {
-            Var(V(l, n)) => Var(V(v.visit_label(l)?, *n)),
-            Lam(l, t, e) => {
-                let t = v.visit_subexpr(t)?;
-                let (l, e) = v.visit_binder(l, e)?;
-                Lam(l, t, e)
-            }
-            Pi(l, t, e) => {
-                let t = v.visit_subexpr(t)?;
-                let (l, e) = v.visit_binder(l, e)?;
-                Pi(l, t, e)
-            }
-            Let(l, t, a, e) => {
-                let t = opt(t, &mut |e| v.visit_subexpr(e))?;
-                let a = v.visit_subexpr(a)?;
-                let (l, e) = v.visit_binder(l, e)?;
-                Let(l, t, a, e)
-            }
-            App(f, a) => App(v.visit_subexpr(f)?, v.visit_subexpr(a)?),
-            Annot(x, t) => Annot(v.visit_subexpr(x)?, v.visit_subexpr(t)?),
-            Const(k) => Const(*k),
-            Builtin(v) => Builtin(*v),
-            BoolLit(b) => BoolLit(*b),
-            NaturalLit(n) => NaturalLit(*n),
-            IntegerLit(n) => IntegerLit(*n),
-            DoubleLit(n) => DoubleLit(*n),
-            TextLit(t) => TextLit(t.traverse_ref(|e| v.visit_subexpr(e))?),
-            BinOp(o, x, y) => {
-                BinOp(*o, v.visit_subexpr(x)?, v.visit_subexpr(y)?)
-            }
-            BoolIf(b, t, f) => BoolIf(
-                v.visit_subexpr(b)?,
-                v.visit_subexpr(t)?,
-                v.visit_subexpr(f)?,
-            ),
-            EmptyListLit(t) => EmptyListLit(v.visit_subexpr(t)?),
-            NEListLit(es) => NEListLit(vec(es, |e| v.visit_subexpr(e))?),
-            OldOptionalLit(x, t) => OldOptionalLit(
-                opt(x, |e| v.visit_subexpr(e))?,
-                v.visit_subexpr(t)?,
-            ),
-            SomeLit(e) => SomeLit(v.visit_subexpr(e)?),
-            RecordType(kts) => RecordType(btmap(kts, v)?),
-            RecordLit(kvs) => RecordLit(btmap(kvs, v)?),
-            UnionType(kts) => UnionType(btoptmap(kts, v)?),
-            UnionLit(k, x, kts) => UnionLit(
-                v.visit_label(k)?,
-                v.visit_subexpr(x)?,
-                btoptmap(kts, v)?,
-            ),
-            Merge(x, y, t) => Merge(
-                v.visit_subexpr(x)?,
-                v.visit_subexpr(y)?,
-                opt(t, |e| v.visit_subexpr(e))?,
-            ),
-            Field(e, l) => Field(v.visit_subexpr(e)?, v.visit_label(l)?),
-            Projection(e, ls) => {
-                Projection(v.visit_subexpr(e)?, vec(ls, |l| v.visit_label(l))?)
-            }
-            Embed(a) => return v.visit_embed_squash(a),
-        })
-    }
-}
-
-/// Like ExprFVeryGenericVisitor, but sets the return
-/// type to ExprF<_>
-pub trait ExprFFallibleVisitor<'a, SE1, SE2, L1, L2, E1, E2>: Sized {
-    type Error;
-
-    fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error>;
-    fn visit_label(&mut self, label: &'a L1) -> Result<L2, Self::Error>;
-    fn visit_embed(self, embed: &'a E1) -> Result<E2, Self::Error>;
-
-    fn visit_subexpr_under_binder(
-        mut self,
-        _label: &'a L1,
-        subexpr: &'a SE1,
-    ) -> Result<SE2, Self::Error> {
-        self.visit_subexpr(subexpr)
-    }
-
-    fn visit_binder(
-        mut self,
-        label: &'a L1,
-        subexpr: &'a SE1,
-    ) -> Result<(L2, SE2), Self::Error> {
-        Ok((
-            self.visit_label(label)?,
-            self.visit_subexpr_under_binder(label, subexpr)?,
-        ))
-    }
-
-    fn visit_embed_squash(
-        self,
-        embed: &'a E1,
-    ) -> Result<ExprF<SE2, L2, E2>, Self::Error> {
-        Ok(ExprF::Embed(self.visit_embed(embed)?))
-    }
-}
-
-impl<'a, T, SE1, SE2, L1, L2, E1, E2>
-    ExprFVeryGenericVisitor<'a, ExprF<SE2, L2, E2>, SE1, L1, E1> for T
-where
-    T: ExprFFallibleVisitor<'a, SE1, SE2, L1, L2, E1, E2>,
-{
-    type Error = T::Error;
-    type SE2 = SE2;
-    type L2 = L2;
-    type E2 = E2;
-
-    fn visit_subexpr(
-        &mut self,
-        subexpr: &'a SE1,
-    ) -> Result<Self::SE2, Self::Error> {
-        self.visit_subexpr(subexpr)
-    }
-
-    fn visit_label(&mut self, label: &'a L1) -> Result<Self::L2, Self::Error> {
-        self.visit_label(label)
-    }
-
-    fn visit_binder(
-        self,
-        label: &'a L1,
-        subexpr: &'a SE1,
-    ) -> Result<(Self::L2, Self::SE2), Self::Error> {
-        self.visit_binder(label, subexpr)
-    }
-
-    fn visit_embed_squash(
-        self,
-        embed: &'a E1,
-    ) -> Result<ExprF<SE2, L2, E2>, Self::Error> {
-        self.visit_embed_squash(embed)
-    }
-
-    // Called with the result of the map, in the non-embed case.
-    // Useful to change the result type, and/or avoid some loss of info
-    fn visit_resulting_exprf(
-        result: ExprF<Self::SE2, Self::L2, Self::E2>,
-    ) -> Result<ExprF<SE2, L2, E2>, Self::Error> {
-        Ok(result)
-    }
-}
-
-/// Like ExprFFallibleVisitor, but without the error handling.
-pub trait ExprFInFallibleVisitor<'a, SE1, SE2, L1, L2, E1, E2>: Sized {
-    fn visit_subexpr(&mut self, subexpr: &'a SE1) -> SE2;
-    fn visit_label(&mut self, label: &'a L1) -> L2;
-    fn visit_embed(self, embed: &'a E1) -> E2;
-
-    fn visit_subexpr_under_binder(
-        mut self,
-        _label: &'a L1,
-        subexpr: &'a SE1,
-    ) -> SE2 {
-        self.visit_subexpr(subexpr)
-    }
-
-    fn visit_binder(mut self, label: &'a L1, subexpr: &'a SE1) -> (L2, SE2) {
-        (
-            self.visit_label(label),
-            self.visit_subexpr_under_binder(label, subexpr),
-        )
-    }
-
-    fn visit_embed_squash(self, embed: &'a E1) -> ExprF<SE2, L2, E2> {
-        ExprF::Embed(self.visit_embed(embed))
-    }
-}
-
-struct InfallibleWrapper<T>(T);
-
-impl<'a, T, SE1, SE2, L1, L2, E1, E2>
-    ExprFFallibleVisitor<'a, SE1, SE2, L1, L2, E1, E2> for InfallibleWrapper<T>
-where
-    T: ExprFInFallibleVisitor<'a, SE1, SE2, L1, L2, E1, E2>,
-{
-    type Error = X;
-
-    fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error> {
-        Ok(self.0.visit_subexpr(subexpr))
-    }
-    fn visit_label(&mut self, label: &'a L1) -> Result<L2, Self::Error> {
-        Ok(self.0.visit_label(label))
-    }
-    fn visit_embed(self, embed: &'a E1) -> Result<E2, Self::Error> {
-        Ok(self.0.visit_embed(embed))
-    }
-
-    fn visit_binder(
-        self,
-        label: &'a L1,
-        subexpr: &'a SE1,
-    ) -> Result<(L2, SE2), Self::Error> {
-        Ok(self.0.visit_binder(label, subexpr))
-    }
-
-    fn visit_embed_squash(
-        self,
-        embed: &'a E1,
-    ) -> Result<ExprF<SE2, L2, E2>, Self::Error> {
-        Ok(self.0.visit_embed_squash(embed))
-    }
-}
-
-impl<'a, T, SE1, SE2, L1, L2, E1, E2>
-    GenericVisitor<&'a ExprF<SE1, L1, E1>, ExprF<SE2, L2, E2>> for T
-where
-    L1: Ord,
-    L2: Ord,
-    T: ExprFInFallibleVisitor<'a, SE1, SE2, L1, L2, E1, E2>,
-{
-    fn visit(self, input: &'a ExprF<SE1, L1, E1>) -> ExprF<SE2, L2, E2> {
-        trivial_result(InfallibleWrapper(self).visit(input))
-    }
-}
-
-pub struct TraverseRefWithBindersVisitor<F1, F2, F4, F5> {
-    pub visit_subexpr: F1,
-    pub visit_under_binder: F2,
-    pub visit_embed: F4,
-    pub visit_label: F5,
-}
-
-impl<'a, SE, L, E, SE2, L2, E2, Err, F1, F2, F4, F5>
-    ExprFFallibleVisitor<'a, SE, SE2, L, L2, E, E2>
-    for TraverseRefWithBindersVisitor<F1, F2, F4, F5>
-where
-    SE: 'a,
-    L: 'a,
-    E: 'a,
-    L: Ord,
-    L2: Ord,
-    F1: FnMut(&'a SE) -> Result<SE2, Err>,
-    F2: FnOnce(&'a L, &'a SE) -> Result<SE2, Err>,
-    F4: FnOnce(&'a E) -> Result<E2, Err>,
-    F5: FnMut(&'a L) -> Result<L2, Err>,
-{
-    type Error = Err;
-
-    fn visit_subexpr(&mut self, subexpr: &'a SE) -> Result<SE2, Self::Error> {
-        (self.visit_subexpr)(subexpr)
-    }
-    fn visit_subexpr_under_binder(
-        self,
-        label: &'a L,
-        subexpr: &'a SE,
-    ) -> Result<SE2, Self::Error> {
-        (self.visit_under_binder)(label, subexpr)
-    }
-    fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
-        (self.visit_embed)(embed)
-    }
-    fn visit_label(&mut self, label: &'a L) -> Result<L2, Self::Error> {
-        (self.visit_label)(label)
-    }
-}
-
-pub struct TraverseRefVisitor<F1, F3, F4> {
-    pub visit_subexpr: F1,
-    pub visit_embed: F3,
-    pub visit_label: F4,
-}
-
-impl<'a, SE, L, E, SE2, L2, E2, Err, F1, F3, F4>
-    ExprFFallibleVisitor<'a, SE, SE2, L, L2, E, E2>
-    for TraverseRefVisitor<F1, F3, F4>
-where
-    SE: 'a,
-    L: 'a,
-    E: 'a,
-    L: Ord,
-    L2: Ord,
-    F1: FnMut(&'a SE) -> Result<SE2, Err>,
-    F3: FnOnce(&'a E) -> Result<E2, Err>,
-    F4: FnMut(&'a L) -> Result<L2, Err>,
-{
-    type Error = Err;
-
-    fn visit_subexpr(&mut self, subexpr: &'a SE) -> Result<SE2, Self::Error> {
-        (self.visit_subexpr)(subexpr)
-    }
-    fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
-        (self.visit_embed)(embed)
-    }
-    fn visit_label(&mut self, label: &'a L) -> Result<L2, Self::Error> {
-        (self.visit_label)(label)
-    }
-}
-
-pub struct TraverseEmbedVisitor<F1>(pub F1);
-
-impl<'a, 'b, N, E, E2, Err, F1>
-    ExprFFallibleVisitor<'a, SubExpr<N, E>, SubExpr<N, E2>, Label, Label, E, E2>
-    for &'b mut TraverseEmbedVisitor<F1>
-where
-    N: Clone + 'a,
-    F1: FnMut(&E) -> Result<E2, Err>,
-{
-    type Error = Err;
-
-    fn visit_subexpr(
-        &mut self,
-        subexpr: &'a SubExpr<N, E>,
-    ) -> Result<SubExpr<N, E2>, Self::Error> {
-        Ok(subexpr.rewrap(subexpr.as_ref().visit(&mut **self)?))
-    }
-    fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
-        (self.0)(embed)
-    }
-    fn visit_label(&mut self, label: &'a Label) -> Result<Label, Self::Error> {
-        Ok(Label::clone(label))
-    }
-}
-
-pub struct NoteAbsurdVisitor;
-
-impl<'a, 'b, N, E>
-    ExprFInFallibleVisitor<'a, SubExpr<X, E>, SubExpr<N, E>, Label, Label, E, E>
-    for &'b mut NoteAbsurdVisitor
-where
-    E: Clone + 'a,
-{
-    fn visit_subexpr(&mut self, subexpr: &'a SubExpr<X, E>) -> SubExpr<N, E> {
-        SubExpr::from_expr_no_note(subexpr.as_ref().visit(&mut **self))
-    }
-    fn visit_embed(self, embed: &'a E) -> E {
-        E::clone(embed)
-    }
-    fn visit_label(&mut self, label: &'a Label) -> Label {
-        Label::clone(label)
-    }
-}
-
-pub struct AbsurdVisitor;
-
-impl<'a, 'b, N, E>
-    ExprFInFallibleVisitor<'a, SubExpr<X, X>, SubExpr<N, E>, Label, Label, X, E>
-    for &'b mut AbsurdVisitor
-{
-    fn visit_subexpr(&mut self, subexpr: &'a SubExpr<X, X>) -> SubExpr<N, E> {
-        SubExpr::from_expr_no_note(subexpr.as_ref().visit(&mut **self))
-    }
-    fn visit_embed(self, embed: &'a X) -> E {
-        match *embed {}
-    }
-    fn visit_label(&mut self, label: &'a Label) -> Label {
-        Label::clone(label)
-    }
-}