Implement Hash for ParsedSubExpr

4 files changed, 58 insertions, 29 deletions

diff --git a/dhall/src/phase/binary.rs b/dhall/src/phase/binary.rs
index b3a80aa..9ed823c 100644
--- a/dhall/src/phase/binary.rs
+++ b/dhall/src/phase/binary.rs
@@ -10,7 +10,7 @@ use dhall_syntax::{
 };
 
 use crate::error::{DecodeError, EncodeError};
-use crate::phase::{DecodedSubExpr, ParsedSubExpr};
+use crate::phase::DecodedSubExpr;
 
 pub fn decode(data: &[u8]) -> Result<DecodedSubExpr, DecodeError> {
     match serde_cbor::de::from_slice(data) {
@@ -19,7 +19,7 @@ pub fn decode(data: &[u8]) -> Result<DecodedSubExpr, DecodeError> {
     }
 }
 
-pub fn encode(expr: &ParsedSubExpr) -> Result<Vec<u8>, EncodeError> {
+pub fn encode<E>(expr: &SubExpr<E>) -> Result<Vec<u8>, EncodeError> {
     serde_cbor::ser::to_vec(&Serialize::Expr(expr))
         .map_err(|e| EncodeError::CBORError(e))
 }
@@ -423,11 +423,11 @@ where
         .collect::<Result<_, _>>()
 }
 
-enum Serialize<'a> {
-    Expr(&'a ParsedSubExpr),
+enum Serialize<'a, E> {
+    Expr(&'a SubExpr<E>),
     CBOR(cbor::Value),
-    RecordMap(&'a DupTreeMap<Label, ParsedSubExpr>),
-    UnionMap(&'a DupTreeMap<Label, Option<ParsedSubExpr>>),
+    RecordMap(&'a DupTreeMap<Label, SubExpr<E>>),
+    UnionMap(&'a DupTreeMap<Label, Option<SubExpr<E>>>),
 }
 
 macro_rules! count {
@@ -447,7 +447,7 @@ macro_rules! ser_seq {
     }};
 }
 
-fn serialize_subexpr<S>(ser: S, e: &ParsedSubExpr) -> Result<S::Ok, S::Error>
+fn serialize_subexpr<S, E>(ser: S, e: &SubExpr<E>) -> Result<S::Ok, S::Error>
 where
     S: serde::ser::Serializer,
 {
@@ -457,21 +457,14 @@ where
     use std::iter::once;
 
     use self::Serialize::{RecordMap, UnionMap};
-    fn expr(x: &ParsedSubExpr) -> self::Serialize<'_> {
+    fn expr<E>(x: &SubExpr<E>) -> self::Serialize<'_, E> {
         self::Serialize::Expr(x)
     }
-    fn cbor<'a>(v: cbor::Value) -> self::Serialize<'a> {
-        self::Serialize::CBOR(v)
-    }
-    fn tag<'a>(x: u64) -> self::Serialize<'a> {
-        cbor(U64(x))
-    }
-    fn null<'a>() -> self::Serialize<'a> {
-        cbor(cbor::Value::Null)
-    }
-    fn label<'a>(l: &Label) -> self::Serialize<'a> {
-        cbor(cbor::Value::String(l.into()))
-    }
+    let cbor =
+        |v: cbor::Value| -> self::Serialize<'_, E> { self::Serialize::CBOR(v) };
+    let tag = |x: u64| cbor(U64(x));
+    let null = || cbor(cbor::Value::Null);
+    let label = |l: &Label| cbor(cbor::Value::String(l.into()));
 
     match e.as_ref() {
         Const(c) => ser.serialize_str(&c.to_string()),
@@ -634,12 +627,14 @@ where
             match &url.headers {
                 None => ser_seq.serialize_element(&Null)?,
                 Some(location_hashed) => {
-                    ser_seq.serialize_element(&self::Serialize::Expr(&rc(
+                    let e = rc(
                         ExprF::Import(dhall_syntax::Import {
                             mode: ImportMode::Code,
                             location_hashed: location_hashed.as_ref().clone(),
                         }),
-                    )))?
+                    );
+                    let s: Serialize<'_, ()> = self::Serialize::Expr(&e);
+                    ser_seq.serialize_element(&s)?
                 }
             };
             ser_seq.serialize_element(&url.authority)?;
@@ -665,7 +660,7 @@ where
     ser_seq.end()
 }
 
-impl<'a> serde::ser::Serialize for Serialize<'a> {
+impl<'a, E> serde::ser::Serialize for Serialize<'a, E> {
     fn serialize<S>(&self, ser: S) -> Result<S::Ok, S::Error>
     where
         S: serde::ser::Serializer,
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index a1e3f29..b73597c 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -157,6 +157,10 @@ impl Typed {
 }
 
 impl Normalized {
+    pub fn encode(&self) -> Result<Vec<u8>, EncodeError> {
+        crate::phase::binary::encode(&self.to_expr())
+    }
+
     #[allow(dead_code)]
     pub fn to_expr(&self) -> NormalizedSubExpr {
         self.0.to_expr()
@@ -220,6 +224,18 @@ derive_traits_for_wrapper_struct!(Parsed);
 derive_traits_for_wrapper_struct!(Resolved);
 derive_traits_for_wrapper_struct!(Normalized);
 
+impl std::hash::Hash for Normalized {
+    fn hash<H>(&self, state: &mut H)
+    where
+        H: std::hash::Hasher,
+    {
+        match self.encode() {
+            Ok(vec) => vec.hash(state),
+            Err(_) => {}
+        }
+    }
+}
+
 impl Eq for Typed {}
 impl PartialEq for Typed {
     fn eq(&self, other: &Self) -> bool {
diff --git a/dhall_syntax/src/core/expr.rs b/dhall_syntax/src/core/expr.rs
index e3f8cec..9729efb 100644
--- a/dhall_syntax/src/core/expr.rs
+++ b/dhall_syntax/src/core/expr.rs
@@ -61,6 +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)
@@ -74,7 +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,
@@ -86,7 +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
@@ -103,7 +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,
@@ -134,7 +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,
@@ -179,13 +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`
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)>,