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-rw-r--r--dhall/src/semantics/tck/tyexpr.rs22
-rw-r--r--dhall/src/syntax/ast/expr.rs47
-rw-r--r--dhall/src/syntax/ast/visitor.rs39
3 files changed, 52 insertions, 56 deletions
diff --git a/dhall/src/semantics/tck/tyexpr.rs b/dhall/src/semantics/tck/tyexpr.rs
index a8b8e58..f0fcdd1 100644
--- a/dhall/src/semantics/tck/tyexpr.rs
+++ b/dhall/src/semantics/tck/tyexpr.rs
@@ -36,15 +36,14 @@ impl TyExpr {
/// Converts a value back to the corresponding AST expression.
pub fn to_expr<'a>(&'a self, opts: ToExprOptions) -> NormalizedExpr {
- tyexpr_to_expr(self, opts, &Vec::new())
+ tyexpr_to_expr(self, opts, &mut Vec::new())
}
}
-// TODO: mutate context once map_ref gets simplified
fn tyexpr_to_expr<'a>(
tyexpr: &'a TyExpr,
opts: ToExprOptions,
- ctx: &Vec<&'a Label>,
+ ctx: &mut Vec<&'a Label>,
) -> NormalizedExpr {
rc(match tyexpr.kind() {
TyExprKind::Var(v) if opts.alpha => {
@@ -61,13 +60,16 @@ fn tyexpr_to_expr<'a>(
ExprKind::Var(V(name.clone(), idx))
}
TyExprKind::Expr(e) => {
- let e = e.map_ref_with_special_handling_of_binders(
- |tye| tyexpr_to_expr(tye, opts, ctx),
- |l, tye| {
- let ctx = ctx.iter().copied().chain(Some(l)).collect();
- tyexpr_to_expr(tye, opts, &ctx)
- },
- );
+ let e = e.map_ref_maybe_binder(|l, tye| {
+ if let Some(l) = l {
+ ctx.push(l);
+ }
+ let e = tyexpr_to_expr(tye, opts, ctx);
+ if let Some(_) = l {
+ ctx.pop();
+ }
+ e
+ });
match e {
ExprKind::Lam(_, t, e) if opts.alpha => {
diff --git a/dhall/src/syntax/ast/expr.rs b/dhall/src/syntax/ast/expr.rs
index f22a279..dbe233b 100644
--- a/dhall/src/syntax/ast/expr.rs
+++ b/dhall/src/syntax/ast/expr.rs
@@ -180,29 +180,38 @@ impl<Label> V<Label> {
}
impl<SE, E> ExprKind<SE, E> {
+ pub fn traverse_ref_maybe_binder<'a, SE2, Err>(
+ &'a self,
+ visit: impl FnMut(Option<&'a Label>, &'a SE) -> Result<SE2, Err>,
+ ) -> Result<ExprKind<SE2, E>, Err>
+ where
+ E: Clone,
+ {
+ visitor::TraverseRefMaybeBinderVisitor(visit).visit(self)
+ }
+
pub fn traverse_ref_with_special_handling_of_binders<'a, SE2, Err>(
&'a self,
- visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
- visit_under_binder: impl FnOnce(&'a Label, &'a SE) -> Result<SE2, Err>,
+ mut visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
+ mut visit_under_binder: impl FnMut(&'a Label, &'a SE) -> Result<SE2, Err>,
) -> Result<ExprKind<SE2, E>, Err>
where
E: Clone,
{
- visitor::TraverseRefWithBindersVisitor {
- visit_subexpr,
- visit_under_binder,
- }
- .visit(self)
+ self.traverse_ref_maybe_binder(|l, x| match l {
+ None => visit_subexpr(x),
+ Some(l) => visit_under_binder(l, x),
+ })
}
pub(crate) fn traverse_ref<'a, SE2, Err>(
&'a self,
- visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
+ mut visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
) -> Result<ExprKind<SE2, E>, Err>
where
E: Clone,
{
- visitor::TraverseRefVisitor { visit_subexpr }.visit(self)
+ self.traverse_ref_maybe_binder(|_, e| visit_subexpr(e))
}
fn traverse_mut<'a, Err>(
@@ -212,6 +221,16 @@ impl<SE, E> ExprKind<SE, E> {
visitor::TraverseMutVisitor { visit_subexpr }.visit(self)
}
+ pub fn map_ref_maybe_binder<'a, SE2>(
+ &'a self,
+ mut map: impl FnMut(Option<&'a Label>, &'a SE) -> SE2,
+ ) -> ExprKind<SE2, E>
+ where
+ E: Clone,
+ {
+ trivial_result(self.traverse_ref_maybe_binder(|l, x| Ok(map(l, x))))
+ }
+
pub fn map_ref_with_special_handling_of_binders<'a, SE2>(
&'a self,
mut map_subexpr: impl FnMut(&'a SE) -> SE2,
@@ -220,10 +239,10 @@ impl<SE, E> ExprKind<SE, E> {
where
E: Clone,
{
- trivial_result(self.traverse_ref_with_special_handling_of_binders(
- |x| Ok(map_subexpr(x)),
- |l, x| Ok(map_under_binder(l, x)),
- ))
+ self.map_ref_maybe_binder(|l, x| match l {
+ None => map_subexpr(x),
+ Some(l) => map_under_binder(l, x),
+ })
}
pub fn map_ref<'a, SE2>(
@@ -233,7 +252,7 @@ impl<SE, E> ExprKind<SE, E> {
where
E: Clone,
{
- trivial_result(self.traverse_ref(|x| Ok(map_subexpr(x))))
+ self.map_ref_maybe_binder(|_, e| map_subexpr(e))
}
pub fn map_mut<'a>(&'a mut self, mut map_subexpr: impl FnMut(&'a mut SE)) {
diff --git a/dhall/src/syntax/ast/visitor.rs b/dhall/src/syntax/ast/visitor.rs
index f9fd379..6a1ce7d 100644
--- a/dhall/src/syntax/ast/visitor.rs
+++ b/dhall/src/syntax/ast/visitor.rs
@@ -296,51 +296,26 @@ where
Ok(())
}
-pub struct TraverseRefWithBindersVisitor<F1, F2> {
- pub visit_subexpr: F1,
- pub visit_under_binder: F2,
-}
+pub struct TraverseRefMaybeBinderVisitor<F>(pub F);
-impl<'a, SE, E, SE2, Err, F1, F2> ExprKindVisitor<'a, SE, SE2, E, E>
- for TraverseRefWithBindersVisitor<F1, F2>
+impl<'a, SE, E, SE2, Err, F> ExprKindVisitor<'a, SE, SE2, E, E>
+ for TraverseRefMaybeBinderVisitor<F>
where
SE: 'a,
E: 'a + Clone,
- F1: FnMut(&'a SE) -> Result<SE2, Err>,
- F2: FnOnce(&'a Label, &'a SE) -> Result<SE2, Err>,
+ F: FnMut(Option<&'a Label>, &'a SE) -> Result<SE2, Err>,
{
type Error = Err;
fn visit_subexpr(&mut self, subexpr: &'a SE) -> Result<SE2, Self::Error> {
- (self.visit_subexpr)(subexpr)
+ (self.0)(None, subexpr)
}
fn visit_subexpr_under_binder(
- self,
+ mut self,
label: &'a Label,
subexpr: &'a SE,
) -> Result<SE2, Self::Error> {
- (self.visit_under_binder)(label, subexpr)
- }
- fn visit_embed(self, embed: &'a E) -> Result<E, Self::Error> {
- Ok(embed.clone())
- }
-}
-
-pub struct TraverseRefVisitor<F1> {
- pub visit_subexpr: F1,
-}
-
-impl<'a, SE, E, SE2, Err, F1> ExprKindVisitor<'a, SE, SE2, E, E>
- for TraverseRefVisitor<F1>
-where
- SE: 'a,
- E: 'a + Clone,
- F1: FnMut(&'a SE) -> Result<SE2, Err>,
-{
- type Error = Err;
-
- fn visit_subexpr(&mut self, subexpr: &'a SE) -> Result<SE2, Self::Error> {
- (self.visit_subexpr)(subexpr)
+ (self.0)(Some(label), subexpr)
}
fn visit_embed(self, embed: &'a E) -> Result<E, Self::Error> {
Ok(embed.clone())
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-03 10:06:55 +0000