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-rw-r--r--dhall_syntax/src/core/context.rs2
-rw-r--r--dhall_syntax/src/core/expr.rs186
-rw-r--r--dhall_syntax/src/core/import.rs62
-rw-r--r--dhall_syntax/src/core/text.rs2
-rw-r--r--dhall_syntax/src/core/visitor.rs265
-rw-r--r--dhall_syntax/src/parser.rs42
-rw-r--r--dhall_syntax/src/printer.rs37
7 files changed, 230 insertions, 366 deletions
diff --git a/dhall_syntax/src/core/context.rs b/dhall_syntax/src/core/context.rs
index eeec121..6844baa 100644
--- a/dhall_syntax/src/core/context.rs
+++ b/dhall_syntax/src/core/context.rs
@@ -4,7 +4,7 @@ use std::hash::Hash;
/// A `(Context a)` associates `Text` labels with values of type `a`
///
-/// The `Context` is used for type-checking when `(a = Expr X)`
+/// The `Context` is used for type-checking when `(a = Expr)`
///
/// * You create a `Context` using `empty` and `insert`
/// * You transform a `Context` using `fmap`
diff --git a/dhall_syntax/src/core/expr.rs b/dhall_syntax/src/core/expr.rs
index 0cbece3..30ac4eb 100644
--- a/dhall_syntax/src/core/expr.rs
+++ b/dhall_syntax/src/core/expr.rs
@@ -10,9 +10,15 @@ pub type Double = NaiveDouble;
/// An empty type
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum X {}
+pub enum Void {}
-pub fn trivial_result<T>(x: Result<T, X>) -> T {
+impl std::fmt::Display for Void {
+ fn fmt(&self, _f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+ match *self {}
+ }
+}
+
+pub fn trivial_result<T>(x: Result<T, Void>) -> T {
match x {
Ok(x) => x,
Err(e) => match e {},
@@ -55,6 +61,15 @@ impl PartialEq for NaiveDouble {
impl Eq for NaiveDouble {}
+impl std::hash::Hash for NaiveDouble {
+ fn hash<H>(&self, state: &mut H)
+ where
+ H: std::hash::Hasher,
+ {
+ self.0.to_bits().hash(state)
+ }
+}
+
impl From<f64> for NaiveDouble {
fn from(x: f64) -> Self {
NaiveDouble(x)
@@ -68,7 +83,7 @@ impl From<NaiveDouble> for f64 {
}
/// Constants for a pure type system
-#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Const {
Type,
Kind,
@@ -80,7 +95,7 @@ pub enum Const {
/// The `Label` field is the variable's name (i.e. \"`x`\").
/// The `Int` field is a DeBruijn index.
/// See dhall-lang/standard/semantics.md for details
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct V<Label>(pub Label, pub usize);
// This is only for the specific `Label` type, not generic
@@ -97,7 +112,7 @@ impl<'a> From<&'a Label> for V<Label> {
// Definition order must match precedence order for
// pretty-printing to work correctly
-#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum BinOp {
/// `x ? y`
ImportAlt,
@@ -128,7 +143,7 @@ pub enum BinOp {
}
/// Built-ins
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
pub enum Builtin {
Bool,
Natural,
@@ -162,8 +177,8 @@ pub enum Builtin {
}
// Each node carries an annotation. In practice it's either X (no annotation) or a Span.
-#[derive(Debug)]
-pub struct SubExpr<Embed>(Rc<(Expr<Embed>, Option<Span>)>);
+#[derive(Debug, Clone)]
+pub struct SubExpr<Embed>(Box<(Expr<Embed>, Option<Span>)>);
impl<Embed: PartialEq> std::cmp::PartialEq for SubExpr<Embed> {
fn eq(&self, other: &Self) -> bool {
@@ -173,13 +188,22 @@ impl<Embed: PartialEq> std::cmp::PartialEq for SubExpr<Embed> {
impl<Embed: Eq> std::cmp::Eq for SubExpr<Embed> {}
+impl<Embed: std::hash::Hash> std::hash::Hash for SubExpr<Embed> {
+ fn hash<H>(&self, state: &mut H)
+ where
+ H: std::hash::Hasher,
+ {
+ (self.0).0.hash(state)
+ }
+}
+
pub type Expr<Embed> = ExprF<SubExpr<Embed>, Embed>;
/// Syntax tree for expressions
// Having the recursion out of the enum definition enables writing
// much more generic code and improves pattern-matching behind
// smart pointers.
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub enum ExprF<SubExpr, Embed> {
Const(Const),
/// `x`
@@ -233,7 +257,9 @@ pub enum ExprF<SubExpr, Embed> {
Field(SubExpr, Label),
/// `e.{ x, y, z }`
Projection(SubExpr, DupTreeSet<Label>),
- /// Embeds an import or the result of resolving the import
+ /// `./some/path`
+ Import(Import<SubExpr>),
+ /// Embeds the result of resolving an import
Embed(Embed),
}
@@ -245,92 +271,62 @@ impl<SE, E> ExprF<SE, E> {
v.visit(self)
}
- pub fn traverse_ref_with_special_handling_of_binders<'a, SE2, E2, Err>(
+ 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>,
- visit_embed: impl FnOnce(&'a E) -> Result<E2, Err>,
- ) -> Result<ExprF<SE2, E2>, Err> {
+ ) -> Result<ExprF<SE2, E>, Err>
+ where
+ E: Clone,
+ {
self.visit(visitor::TraverseRefWithBindersVisitor {
visit_subexpr,
visit_under_binder,
- visit_embed,
})
}
- fn traverse_ref<'a, SE2, E2, Err>(
+ fn traverse_ref<'a, SE2, Err>(
&'a self,
visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
- visit_embed: impl FnOnce(&'a E) -> Result<E2, Err>,
- ) -> Result<ExprF<SE2, E2>, Err> {
- self.visit(visitor::TraverseRefVisitor {
- visit_subexpr,
- visit_embed,
- })
+ ) -> Result<ExprF<SE2, E>, Err>
+ where
+ E: Clone,
+ {
+ self.visit(visitor::TraverseRefVisitor { visit_subexpr })
}
- pub fn map_ref_with_special_handling_of_binders<'a, SE2, E2>(
+ pub fn map_ref_with_special_handling_of_binders<'a, SE2>(
&'a self,
mut map_subexpr: impl FnMut(&'a SE) -> SE2,
mut map_under_binder: impl FnMut(&'a Label, &'a SE) -> SE2,
- map_embed: impl FnOnce(&'a E) -> E2,
- ) -> ExprF<SE2, E2> {
+ ) -> ExprF<SE2, 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)),
- |x| Ok(map_embed(x)),
))
}
- pub fn map_ref<'a, SE2, E2>(
+ pub fn map_ref<'a, SE2>(
&'a self,
mut map_subexpr: impl FnMut(&'a SE) -> SE2,
- map_embed: impl FnOnce(&'a E) -> E2,
- ) -> ExprF<SE2, E2> {
- trivial_result(
- self.traverse_ref(|x| Ok(map_subexpr(x)), |x| Ok(map_embed(x))),
- )
- }
-
- pub fn traverse_ref_simple<'a, SE2, Err>(
- &'a self,
- visit_subexpr: impl FnMut(&'a SE) -> Result<SE2, Err>,
- ) -> Result<ExprF<SE2, E>, Err>
- where
- E: Clone,
- {
- self.traverse_ref(visit_subexpr, |x| Ok(E::clone(x)))
- }
-
- pub fn map_ref_simple<'a, SE2>(
- &'a self,
- map_subexpr: impl Fn(&'a SE) -> SE2,
) -> ExprF<SE2, E>
where
E: Clone,
{
- self.map_ref(map_subexpr, E::clone)
+ trivial_result(self.traverse_ref(|x| Ok(map_subexpr(x))))
}
}
impl<E> Expr<E> {
- fn traverse_embed<E2, Err>(
- &self,
- visit_embed: impl FnMut(&E) -> Result<E2, Err>,
- ) -> Result<Expr<E2>, Err> {
- self.visit(&mut visitor::TraverseEmbedVisitor(visit_embed))
- }
-
- fn map_embed<E2>(&self, mut map_embed: impl FnMut(&E) -> E2) -> Expr<E2> {
- trivial_result(self.traverse_embed(|x| Ok(map_embed(x))))
- }
-
pub fn traverse_resolve<E2, Err>(
&self,
- visit_embed: impl FnMut(&E) -> Result<E2, Err>,
+ visit_import: impl FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
) -> Result<Expr<E2>, Err> {
self.traverse_resolve_with_visitor(&mut visitor::ResolveVisitor(
- visit_embed,
+ visit_import,
))
}
@@ -339,35 +335,35 @@ impl<E> Expr<E> {
visitor: &mut visitor::ResolveVisitor<F1>,
) -> Result<Expr<E2>, Err>
where
- F1: FnMut(&E) -> Result<E2, Err>,
+ F1: FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
{
match self {
ExprF::BinOp(BinOp::ImportAlt, l, r) => l
.as_ref()
.traverse_resolve_with_visitor(visitor)
.or(r.as_ref().traverse_resolve_with_visitor(visitor)),
- _ => self.visit(visitor),
+ _ => {
+ let e = self.visit(&mut *visitor)?;
+ Ok(match &e {
+ ExprF::Import(import) => ExprF::Embed((visitor.0)(import)?),
+ _ => e,
+ })
+ }
}
}
}
-impl Expr<X> {
- pub fn absurd<E>(&self) -> Expr<E> {
- self.visit(&mut visitor::AbsurdVisitor)
- }
-}
-
impl<E> SubExpr<E> {
pub fn as_ref(&self) -> &Expr<E> {
&self.0.as_ref().0
}
pub fn new(x: Expr<E>, n: Span) -> Self {
- SubExpr(Rc::new((x, Some(n))))
+ SubExpr(Box::new((x, Some(n))))
}
pub fn from_expr_no_span(x: Expr<E>) -> Self {
- SubExpr(Rc::new((x, None)))
+ SubExpr(Box::new((x, None)))
}
pub fn from_builtin(b: Builtin) -> Self {
@@ -375,56 +371,16 @@ impl<E> SubExpr<E> {
}
pub fn rewrap<E2>(&self, x: Expr<E2>) -> SubExpr<E2> {
- SubExpr(Rc::new((x, (self.0).1.clone())))
- }
-
- pub fn traverse_embed<E2, Err>(
- &self,
- visit_embed: impl FnMut(&E) -> Result<E2, Err>,
- ) -> Result<SubExpr<E2>, Err> {
- Ok(self.rewrap(self.as_ref().traverse_embed(visit_embed)?))
- }
-
- pub fn map_embed<E2>(
- &self,
- map_embed: impl FnMut(&E) -> E2,
- ) -> SubExpr<E2> {
- self.rewrap(self.as_ref().map_embed(map_embed))
- }
-
- pub fn map_subexprs_with_special_handling_of_binders<'a>(
- &'a self,
- map_expr: impl FnMut(&'a Self) -> Self,
- map_under_binder: impl FnMut(&'a Label, &'a Self) -> Self,
- ) -> Self {
- match self.as_ref() {
- ExprF::Embed(_) => SubExpr::clone(self),
- // This calls ExprF::map_ref
- e => self.rewrap(e.map_ref_with_special_handling_of_binders(
- map_expr,
- map_under_binder,
- |_| unreachable!(),
- )),
- }
+ SubExpr(Box::new((x, (self.0).1.clone())))
}
+}
+impl<E> SubExpr<E> {
pub fn traverse_resolve<E2, Err>(
&self,
- visit_embed: impl FnMut(&E) -> Result<E2, Err>,
+ visit_import: impl FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
) -> Result<SubExpr<E2>, Err> {
- Ok(self.rewrap(self.as_ref().traverse_resolve(visit_embed)?))
- }
-}
-
-impl SubExpr<X> {
- pub fn absurd<T>(&self) -> SubExpr<T> {
- SubExpr::from_expr_no_span(self.as_ref().absurd())
- }
-}
-
-impl<E> Clone for SubExpr<E> {
- fn clone(&self) -> Self {
- SubExpr(Rc::clone(&self.0))
+ Ok(self.rewrap(self.as_ref().traverse_resolve(visit_import)?))
}
}
diff --git a/dhall_syntax/src/core/import.rs b/dhall_syntax/src/core/import.rs
index d41eae2..9329d48 100644
--- a/dhall_syntax/src/core/import.rs
+++ b/dhall_syntax/src/core/import.rs
@@ -13,21 +13,20 @@ pub enum FilePrefix {
/// The location of import (i.e. local vs. remote vs. environment)
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub enum ImportLocation {
+pub enum ImportLocation<SubExpr> {
Local(FilePrefix, Vec<String>),
- Remote(URL),
+ Remote(URL<SubExpr>),
Env(String),
Missing,
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct URL {
+pub struct URL<SubExpr> {
pub scheme: Scheme,
pub authority: String,
pub path: Vec<String>,
pub query: Option<String>,
- // TODO: implement inline headers
- pub headers: Option<Box<ImportHashed>>,
+ pub headers: Option<SubExpr>,
}
#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -49,15 +48,54 @@ pub enum Hash {
SHA256(Vec<u8>),
}
+/// Reference to an external resource
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct ImportHashed {
- pub location: ImportLocation,
+pub struct Import<SubExpr> {
+ pub mode: ImportMode,
+ pub location: ImportLocation<SubExpr>,
pub hash: Option<Hash>,
}
-/// Reference to an external resource
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct Import {
- pub mode: ImportMode,
- pub location_hashed: ImportHashed,
+impl<SE> URL<SE> {
+ pub fn visit_subexpr<'a, Err, SE2>(
+ &'a self,
+ f: impl FnOnce(&'a SE) -> Result<SE2, Err>,
+ ) -> Result<URL<SE2>, Err> {
+ let headers = self.headers.as_ref().map(f).transpose()?;
+ Ok(URL {
+ scheme: self.scheme,
+ authority: self.authority.clone(),
+ path: self.path.clone(),
+ query: self.query.clone(),
+ headers,
+ })
+ }
+}
+
+impl<SE> ImportLocation<SE> {
+ pub fn visit_subexpr<'a, Err, SE2>(
+ &'a self,
+ f: impl FnOnce(&'a SE) -> Result<SE2, Err>,
+ ) -> Result<ImportLocation<SE2>, Err> {
+ use ImportLocation::*;
+ Ok(match self {
+ Local(prefix, path) => Local(prefix.clone(), path.clone()),
+ Remote(url) => Remote(url.visit_subexpr(f)?),
+ Env(env) => Env(env.clone()),
+ Missing => Missing,
+ })
+ }
+}
+
+impl<SE> Import<SE> {
+ pub fn visit_subexpr<'a, Err, SE2>(
+ &'a self,
+ f: impl FnOnce(&'a SE) -> Result<SE2, Err>,
+ ) -> Result<Import<SE2>, Err> {
+ Ok(Import {
+ mode: self.mode,
+ location: self.location.visit_subexpr(f)?,
+ hash: self.hash.clone(),
+ })
+ }
}
diff --git a/dhall_syntax/src/core/text.rs b/dhall_syntax/src/core/text.rs
index 0ce1e6f..10fd68a 100644
--- a/dhall_syntax/src/core/text.rs
+++ b/dhall_syntax/src/core/text.rs
@@ -1,6 +1,6 @@
use std::iter::FromIterator;
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct InterpolatedText<SubExpr> {
head: String,
tail: Vec<(SubExpr, String)>,
diff --git a/dhall_syntax/src/core/visitor.rs b/dhall_syntax/src/core/visitor.rs
index 50ec68a..7b4ed4b 100644
--- a/dhall_syntax/src/core/visitor.rs
+++ b/dhall_syntax/src/core/visitor.rs
@@ -2,52 +2,56 @@ use crate::*;
use std::iter::FromIterator;
/// A way too generic Visitor trait.
-pub trait GenericVisitor<Input, Return>: Sized {
- fn visit(self, input: Input) -> Return;
+pub trait GenericVisitor<Input, Output>: Sized {
+ fn visit(self, input: Input) -> Output;
}
-/// 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, E1>: Sized {
+/// 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_ref_with_special_handling_of_binders` 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.
+pub trait ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>: Sized {
type Error;
- type SE2;
- type E2;
- fn visit_subexpr(
- &mut self,
- subexpr: &'a SE1,
- ) -> Result<Self::SE2, Self::Error>;
+ fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error>;
+ fn visit_embed(self, embed: &'a E1) -> Result<E2, Self::Error>;
fn visit_subexpr_under_binder(
- self,
- label: &'a Label,
+ mut self,
+ _label: &'a Label,
subexpr: &'a SE1,
- ) -> Result<Self::SE2, Self::Error>;
+ ) -> Result<SE2, Self::Error> {
+ self.visit_subexpr(subexpr)
+ }
+}
- fn visit_embed_squash(self, embed: &'a E1) -> Result<Ret, Self::Error>;
+/// Like ExprFFallibleVisitor, but without the error handling.
+pub trait ExprFInFallibleVisitor<'a, SE1, SE2, E1, E2>: Sized {
+ fn visit_subexpr(&mut self, subexpr: &'a SE1) -> SE2;
+ fn visit_embed(self, embed: &'a E1) -> E2;
- // 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::E2>,
- ) -> Result<Ret, Self::Error>;
+ fn visit_subexpr_under_binder(
+ mut self,
+ _label: &'a Label,
+ subexpr: &'a SE1,
+ ) -> SE2 {
+ self.visit_subexpr(subexpr)
+ }
}
-impl<'a, T, Ret, SE1, E1>
- GenericVisitor<&'a ExprF<SE1, E1>, Result<Ret, T::Error>> for T
+impl<'a, T, SE1, SE2, E1, E2>
+ GenericVisitor<&'a ExprF<SE1, E1>, Result<ExprF<SE2, E2>, T::Error>> for T
where
- T: ExprFVeryGenericVisitor<'a, Ret, SE1, E1>,
+ T: ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>,
{
- fn visit(self, input: &'a ExprF<SE1, E1>) -> Result<Ret, T::Error> {
+ fn visit(
+ self,
+ input: &'a ExprF<SE1, E1>,
+ ) -> Result<ExprF<SE2, E2>, T::Error> {
fn vec<'a, T, U, Err, F: FnMut(&'a T) -> Result<U, Err>>(
x: &'a [T],
f: F,
@@ -63,27 +67,27 @@ where
None => None,
})
}
- fn dupmap<'a, V, Ret, SE, E, T>(
- x: impl IntoIterator<Item = (&'a Label, &'a SE)>,
+ fn dupmap<'a, V, SE1, SE2, E1, E2, T>(
+ x: impl IntoIterator<Item = (&'a Label, &'a SE1)>,
mut v: V,
) -> Result<T, V::Error>
where
- SE: 'a,
- T: FromIterator<(Label, V::SE2)>,
- V: ExprFVeryGenericVisitor<'a, Ret, SE, E>,
+ SE1: 'a,
+ T: FromIterator<(Label, SE2)>,
+ V: ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>,
{
x.into_iter()
.map(|(k, x)| Ok((k.clone(), v.visit_subexpr(x)?)))
.collect()
}
- fn optdupmap<'a, V, Ret, SE, E, T>(
- x: impl IntoIterator<Item = (&'a Label, &'a Option<SE>)>,
+ fn optdupmap<'a, V, SE1, SE2, E1, E2, T>(
+ x: impl IntoIterator<Item = (&'a Label, &'a Option<SE1>)>,
mut v: V,
) -> Result<T, V::Error>
where
- SE: 'a,
- T: FromIterator<(Label, Option<V::SE2>)>,
- V: ExprFVeryGenericVisitor<'a, Ret, SE, E>,
+ SE1: 'a,
+ T: FromIterator<(Label, Option<SE2>)>,
+ V: ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>,
{
x.into_iter()
.map(|(k, x)| {
@@ -100,7 +104,7 @@ where
let mut v = self;
use crate::ExprF::*;
- T::visit_resulting_exprf(match input {
+ Ok(match input {
Var(v) => Var(v.clone()),
Lam(l, t, e) => {
let t = v.visit_subexpr(t)?;
@@ -149,90 +153,19 @@ where
Field(e, l) => Field(v.visit_subexpr(e)?, l.clone()),
Projection(e, ls) => Projection(v.visit_subexpr(e)?, ls.clone()),
Assert(e) => Assert(v.visit_subexpr(e)?),
- Embed(a) => return v.visit_embed_squash(a),
+ Import(i) => Import(i.visit_subexpr(|e| v.visit_subexpr(e))?),
+ Embed(a) => Embed(v.visit_embed(a)?),
})
}
}
-/// Like ExprFVeryGenericVisitor, but sets the return
-/// type to ExprF<_>
-pub trait ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>: Sized {
- type Error;
-
- fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error>;
- fn visit_embed(self, embed: &'a E1) -> Result<E2, Self::Error>;
-
- fn visit_subexpr_under_binder(
- mut self,
- _label: &'a Label,
- subexpr: &'a SE1,
- ) -> Result<SE2, Self::Error> {
- self.visit_subexpr(subexpr)
- }
-
- fn visit_embed_squash(
- self,
- embed: &'a E1,
- ) -> Result<ExprF<SE2, E2>, Self::Error> {
- Ok(ExprF::Embed(self.visit_embed(embed)?))
- }
-}
-
-impl<'a, T, SE1, SE2, E1, E2>
- ExprFVeryGenericVisitor<'a, ExprF<SE2, E2>, SE1, E1> for T
+impl<'a, T, SE1, SE2, E1, E2> GenericVisitor<&'a ExprF<SE1, E1>, ExprF<SE2, E2>>
+ for T
where
- T: ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>,
+ T: ExprFInFallibleVisitor<'a, SE1, SE2, E1, E2>,
{
- type Error = T::Error;
- type SE2 = SE2;
- type E2 = E2;
-
- fn visit_subexpr(
- &mut self,
- subexpr: &'a SE1,
- ) -> Result<Self::SE2, Self::Error> {
- self.visit_subexpr(subexpr)
- }
-
- fn visit_subexpr_under_binder(
- self,
- label: &'a Label,
- subexpr: &'a SE1,
- ) -> Result<Self::SE2, Self::Error> {
- self.visit_subexpr_under_binder(label, subexpr)
- }
-
- fn visit_embed_squash(
- self,
- embed: &'a E1,
- ) -> Result<ExprF<SE2, 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::E2>,
- ) -> Result<ExprF<SE2, E2>, Self::Error> {
- Ok(result)
- }
-}
-
-/// Like ExprFFallibleVisitor, but without the error handling.
-pub trait ExprFInFallibleVisitor<'a, SE1, SE2, E1, E2>: Sized {
- fn visit_subexpr(&mut self, subexpr: &'a SE1) -> SE2;
- fn visit_embed(self, embed: &'a E1) -> E2;
-
- fn visit_subexpr_under_binder(
- mut self,
- _label: &'a Label,
- subexpr: &'a SE1,
- ) -> SE2 {
- self.visit_subexpr(subexpr)
- }
-
- fn visit_embed_squash(self, embed: &'a E1) -> ExprF<SE2, E2> {
- ExprF::Embed(self.visit_embed(embed))
+ fn visit(self, input: &'a ExprF<SE1, E1>) -> ExprF<SE2, E2> {
+ trivial_result(InfallibleWrapper(self).visit(input))
}
}
@@ -243,7 +176,7 @@ impl<'a, T, SE1, SE2, E1, E2> ExprFFallibleVisitor<'a, SE1, SE2, E1, E2>
where
T: ExprFInFallibleVisitor<'a, SE1, SE2, E1, E2>,
{
- type Error = X;
+ type Error = Void;
fn visit_subexpr(&mut self, subexpr: &'a SE1) -> Result<SE2, Self::Error> {
Ok(self.0.visit_subexpr(subexpr))
@@ -259,40 +192,20 @@ where
) -> Result<SE2, Self::Error> {
Ok(self.0.visit_subexpr_under_binder(label, subexpr))
}
-
- fn visit_embed_squash(
- self,
- embed: &'a E1,
- ) -> Result<ExprF<SE2, E2>, Self::Error> {
- Ok(self.0.visit_embed_squash(embed))
- }
}
-impl<'a, T, SE1, SE2, E1, E2> GenericVisitor<&'a ExprF<SE1, E1>, ExprF<SE2, E2>>
- for T
-where
- T: ExprFInFallibleVisitor<'a, SE1, SE2, E1, E2>,
-{
- fn visit(self, input: &'a ExprF<SE1, E1>) -> ExprF<SE2, E2> {
- trivial_result(InfallibleWrapper(self).visit(input))
- }
-}
-
-pub struct TraverseRefWithBindersVisitor<F1, F2, F4> {
+pub struct TraverseRefWithBindersVisitor<F1, F2> {
pub visit_subexpr: F1,
pub visit_under_binder: F2,
- pub visit_embed: F4,
}
-impl<'a, SE, E, SE2, E2, Err, F1, F2, F4>
- ExprFFallibleVisitor<'a, SE, SE2, E, E2>
- for TraverseRefWithBindersVisitor<F1, F2, F4>
+impl<'a, SE, E, SE2, Err, F1, F2> ExprFFallibleVisitor<'a, SE, SE2, E, E>
+ for TraverseRefWithBindersVisitor<F1, F2>
where
SE: 'a,
- E: 'a,
+ E: 'a + Clone,
F1: FnMut(&'a SE) -> Result<SE2, Err>,
F2: FnOnce(&'a Label, &'a SE) -> Result<SE2, Err>,
- F4: FnOnce(&'a E) -> Result<E2, Err>,
{
type Error = Err;
@@ -306,52 +219,29 @@ where
) -> 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_embed(self, embed: &'a E) -> Result<E, Self::Error> {
+ Ok(embed.clone())
}
}
-pub struct TraverseRefVisitor<F1, F3> {
+pub struct TraverseRefVisitor<F1> {
pub visit_subexpr: F1,
- pub visit_embed: F3,
}
-impl<'a, SE, E, SE2, E2, Err, F1, F3> ExprFFallibleVisitor<'a, SE, SE2, E, E2>
- for TraverseRefVisitor<F1, F3>
+impl<'a, SE, E, SE2, Err, F1> ExprFFallibleVisitor<'a, SE, SE2, E, E>
+ for TraverseRefVisitor<F1>
where
SE: 'a,
- E: 'a,
+ E: 'a + Clone,
F1: FnMut(&'a SE) -> Result<SE2, Err>,
- F3: FnOnce(&'a E) -> Result<E2, 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)
- }
-}
-
-pub struct TraverseEmbedVisitor<F1>(pub F1);
-
-impl<'a, 'b, E, E2, Err, F1>
- ExprFFallibleVisitor<'a, SubExpr<E>, SubExpr<E2>, E, E2>
- for &'b mut TraverseEmbedVisitor<F1>
-where
- F1: FnMut(&E) -> Result<E2, Err>,
-{
- type Error = Err;
-
- fn visit_subexpr(
- &mut self,
- subexpr: &'a SubExpr<E>,
- ) -> Result<SubExpr<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_embed(self, embed: &'a E) -> Result<E, Self::Error> {
+ Ok(embed.clone())
}
}
@@ -361,7 +251,7 @@ impl<'a, 'b, E, E2, Err, F1>
ExprFFallibleVisitor<'a, SubExpr<E>, SubExpr<E2>, E, E2>
for &'b mut ResolveVisitor<F1>
where
- F1: FnMut(&E) -> Result<E2, Err>,
+ F1: FnMut(&Import<SubExpr<E2>>) -> Result<E2, Err>,
{
type Error = Err;
@@ -375,20 +265,7 @@ where
.traverse_resolve_with_visitor(&mut **self)?,
))
}
- fn visit_embed(self, embed: &'a E) -> Result<E2, Self::Error> {
- (self.0)(embed)
- }
-}
-
-pub struct AbsurdVisitor;
-
-impl<'a, 'b, E> ExprFInFallibleVisitor<'a, SubExpr<X>, SubExpr<E>, X, E>
- for &'b mut AbsurdVisitor
-{
- fn visit_subexpr(&mut self, subexpr: &'a SubExpr<X>) -> SubExpr<E> {
- SubExpr::from_expr_no_span(subexpr.as_ref().visit(&mut **self))
- }
- fn visit_embed(self, embed: &'a X) -> E {
- match *embed {}
+ fn visit_embed(self, _embed: &'a E) -> Result<E2, Self::Error> {
+ unimplemented!()
}
}
diff --git a/dhall_syntax/src/parser.rs b/dhall_syntax/src/parser.rs
index 1ab6e6d..8ecd0ab 100644
--- a/dhall_syntax/src/parser.rs
+++ b/dhall_syntax/src/parser.rs
@@ -15,10 +15,10 @@ use crate::*;
// their own crate because they are quite general and useful. For now they
// are here and hopefully you can figure out how they work.
-pub(crate) type ParsedExpr = Expr<Import>;
-pub(crate) type ParsedSubExpr = SubExpr<Import>;
-type ParsedText = InterpolatedText<SubExpr<Import>>;
-type ParsedTextContents = InterpolatedTextContents<SubExpr<Import>>;
+pub(crate) type ParsedExpr = Expr<Void>;
+pub(crate) type ParsedSubExpr = SubExpr<Void>;
+type ParsedText = InterpolatedText<ParsedSubExpr>;
+type ParsedTextContents = InterpolatedTextContents<ParsedSubExpr>;
pub type ParseError = pest::error::Error<Rule>;
@@ -598,7 +598,7 @@ make_parser! {
_ => unreachable!(),
});
- rule!(http_raw<URL>; children!(
+ rule!(http_raw<URL<ParsedSubExpr>>; children!(
[scheme(sch), authority(auth), path(p)] => URL {
scheme: sch,
authority: auth,
@@ -619,10 +619,10 @@ make_parser! {
rule!(query<String>; captured_str!(s) => s.to_owned());
- rule!(http<URL>; children!(
+ rule!(http<URL<ParsedSubExpr>>; children!(
[http_raw(url)] => url,
- [http_raw(url), import_hashed(ih)] =>
- URL { headers: Some(Box::new(ih)), ..url },
+ [http_raw(url), expression(e)] =>
+ URL { headers: Some(e), ..url },
));
rule!(env<String>; children!(
@@ -654,7 +654,7 @@ make_parser! {
token_rule!(missing<()>);
- rule!(import_type<ImportLocation>; children!(
+ rule!(import_type<ImportLocation<ParsedSubExpr>>; children!(
[missing(_)] => {
ImportLocation::Missing
},
@@ -679,33 +679,33 @@ make_parser! {
Hash::SHA256(hex::decode(hash).unwrap())
});
- rule!(import_hashed<ImportHashed>; children!(
+ rule!(import_hashed<crate::Import<ParsedSubExpr>>; children!(
[import_type(location)] =>
- ImportHashed { location, hash: None },
+ crate::Import {mode: ImportMode::Code, location, hash: None },
[import_type(location), hash(h)] =>
- ImportHashed { location, hash: Some(h) },
+ crate::Import {mode: ImportMode::Code, location, hash: Some(h) },
));
token_rule!(Text<()>);
token_rule!(Location<()>);
rule!(import<ParsedSubExpr> as expression; span; children!(
- [import_hashed(location_hashed)] => {
- spanned(span, Embed(Import {
+ [import_hashed(imp)] => {
+ spanned(span, Import(crate::Import {
mode: ImportMode::Code,
- location_hashed
+ ..imp
}))
},
- [import_hashed(location_hashed), Text(_)] => {
- spanned(span, Embed(Import {
+ [import_hashed(imp), Text(_)] => {
+ spanned(span, Import(crate::Import {
mode: ImportMode::RawText,
- location_hashed
+ ..imp
}))
},
- [import_hashed(location_hashed), Location(_)] => {
- spanned(span, Embed(Import {
+ [import_hashed(imp), Location(_)] => {
+ spanned(span, Import(crate::Import {
mode: ImportMode::Location,
- location_hashed
+ ..imp
}))
},
));
diff --git a/dhall_syntax/src/printer.rs b/dhall_syntax/src/printer.rs
index 95eafe5..256ea65 100644
--- a/dhall_syntax/src/printer.rs
+++ b/dhall_syntax/src/printer.rs
@@ -88,6 +88,7 @@ impl<SE: Display + Clone, E: Display> Display for ExprF<SE, E> {
}
Ok(())
})?,
+ Import(a) => a.fmt(f)?,
Embed(a) => a.fmt(f)?,
}
Ok(())
@@ -151,12 +152,14 @@ impl<A: Display + Clone> Expr<A> {
// Precedence is magically handled by the ordering of BinOps.
ExprF::BinOp(op, _, _) if phase > PrintPhase::BinOp(*op) => true,
ExprF::App(_, _) if phase > PrintPhase::App => true,
- Field(_, _) | Projection(_, _) if phase > Import => true,
+ Field(_, _) | Projection(_, _) if phase > PrintPhase::Import => {
+ true
+ }
_ => false,
};
// Annotate subexpressions with the appropriate phase, defaulting to Base
- let phased_self = match self.map_ref_simple(|e| PhasedExpr(e, Base)) {
+ let phased_self = match self.map_ref(|e| PhasedExpr(e, Base)) {
Pi(a, b, c) => {
if &String::from(&a) == "_" {
Pi(a, b.phase(Operator), c)
@@ -165,8 +168,8 @@ impl<A: Display + Clone> Expr<A> {
}
}
Merge(a, b, c) => Merge(
- a.phase(Import),
- b.phase(Import),
+ a.phase(PrintPhase::Import),
+ b.phase(PrintPhase::Import),
c.map(|x| x.phase(PrintPhase::App)),
),
Annot(a, b) => Annot(a.phase(Operator), b),
@@ -175,8 +178,11 @@ impl<A: Display + Clone> Expr<A> {
a.phase(PrintPhase::BinOp(op)),
b.phase(PrintPhase::BinOp(op)),
),
- SomeLit(e) => SomeLit(e.phase(Import)),
- ExprF::App(f, a) => ExprF::App(f.phase(Import), a.phase(Import)),
+ SomeLit(e) => SomeLit(e.phase(PrintPhase::Import)),
+ ExprF::App(f, a) => ExprF::App(
+ f.phase(PrintPhase::Import),
+ a.phase(PrintPhase::Import),
+ ),
Field(a, b) => Field(a.phase(Primitive), b),
Projection(e, ls) => Projection(e.phase(Primitive), ls),
e => e,
@@ -224,7 +230,7 @@ where
f.write_str(close)
}
-impl<SubExpr: Display + Clone> Display for InterpolatedText<SubExpr> {
+impl<SubExpr: Display> Display for InterpolatedText<SubExpr> {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
f.write_str("\"")?;
for x in self.iter() {
@@ -338,10 +344,11 @@ impl Display for Hash {
}
}
}
-impl Display for ImportHashed {
+impl<SubExpr: Display> Display for Import<SubExpr> {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
use FilePrefix::*;
use ImportLocation::*;
+ use ImportMode::*;
let fmt_remote_path_component = |s: &str| -> String {
use percent_encoding::{
utf8_percent_encode, PATH_SEGMENT_ENCODE_SET,
@@ -417,14 +424,6 @@ impl Display for ImportHashed {
write!(f, " ")?;
hash.fmt(f)?;
}
- Ok(())
- }
-}
-
-impl Display for Import {
- fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
- self.location_hashed.fmt(f)?;
- use ImportMode::*;
match self.mode {
Code => {}
RawText => write!(f, " as Text")?,
@@ -491,9 +490,3 @@ impl<Label: Display> Display for V<Label> {
Ok(())
}
}
-
-impl Display for X {
- fn fmt(&self, _: &mut fmt::Formatter) -> Result<(), fmt::Error> {
- match *self {}
- }
-}