1 files changed, 55 insertions, 53 deletions

diff --git a/tvix/eval/src/value/list.rs b/tvix/eval/src/value/list.rs
index 81abb3c07e..2b8b3de28d 100644
--- a/tvix/eval/src/value/list.rs
+++ b/tvix/eval/src/value/list.rs
@@ -1,21 +1,25 @@
 //! This module implements Nix lists.
-use std::fmt::Display;
+use std::ops::Index;
+use std::rc::Rc;
 
-use crate::errors::ErrorKind;
-use crate::vm::VM;
+use imbl::{vector, Vector};
 
+use serde::Deserialize;
+
+use super::thunk::ThunkSet;
+use super::TotalDisplay;
 use super::Value;
 
 #[repr(transparent)]
-#[derive(Clone, Debug, PartialEq)]
-pub struct NixList(Vec<Value>);
+#[derive(Clone, Debug, Deserialize)]
+pub struct NixList(Rc<Vector<Value>>);
 
-impl Display for NixList {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+impl TotalDisplay for NixList {
+    fn total_fmt(&self, f: &mut std::fmt::Formatter<'_>, set: &mut ThunkSet) -> std::fmt::Result {
         f.write_str("[ ")?;
 
-        for v in &self.0 {
-            v.fmt(f)?;
+        for v in self {
+            v.total_fmt(f, set)?;
             f.write_str(" ")?;
         }
 
@@ -23,39 +27,13 @@ impl Display for NixList {
     }
 }
 
-impl From<Vec<Value>> for NixList {
-    fn from(vs: Vec<Value>) -> Self {
-        Self(vs)
-    }
-}
-
-#[cfg(feature = "arbitrary")]
-mod arbitrary {
-    use proptest::{
-        prelude::{any_with, Arbitrary},
-        strategy::{BoxedStrategy, Strategy},
-    };
-
-    use super::*;
-
-    impl Arbitrary for NixList {
-        type Parameters = <Vec<Value> as Arbitrary>::Parameters;
-        type Strategy = BoxedStrategy<Self>;
-
-        fn arbitrary_with(args: Self::Parameters) -> Self::Strategy {
-            any_with::<Vec<Value>>(args).prop_map(Self).boxed()
-        }
+impl From<Vector<Value>> for NixList {
+    fn from(vs: Vector<Value>) -> Self {
+        Self(Rc::new(vs))
     }
 }
 
 impl NixList {
-    pub fn concat(&self, other: &Self) -> Self {
-        let mut lhs = self.clone();
-        let mut rhs = other.clone();
-        lhs.0.append(&mut rhs.0);
-        lhs
-    }
-
     pub fn len(&self) -> usize {
         self.0.len()
     }
@@ -64,6 +42,10 @@ impl NixList {
         self.0.get(i)
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.0.is_empty()
+    }
+
     pub fn construct(count: usize, stack_slice: Vec<Value>) -> Self {
         debug_assert!(
             count == stack_slice.len(),
@@ -72,29 +54,49 @@ impl NixList {
             stack_slice.len(),
         );
 
-        NixList(stack_slice)
+        NixList(Rc::new(Vector::from_iter(stack_slice)))
     }
 
-    pub fn iter(&self) -> std::slice::Iter<Value> {
+    pub fn iter(&self) -> vector::Iter<Value> {
         self.0.iter()
     }
 
-    pub fn into_iter(self) -> std::vec::IntoIter<Value> {
-        self.0.into_iter()
+    pub fn ptr_eq(&self, other: &Self) -> bool {
+        Rc::ptr_eq(&self.0, &other.0)
     }
 
-    /// Compare `self` against `other` for equality using Nix equality semantics
-    pub fn nix_eq(&self, other: &Self, vm: &mut VM) -> Result<bool, ErrorKind> {
-        if self.len() != other.len() {
-            return Ok(false);
-        }
+    pub fn into_inner(self) -> Vector<Value> {
+        Rc::try_unwrap(self.0).unwrap_or_else(|rc| (*rc).clone())
+    }
 
-        for (v1, v2) in self.iter().zip(other.iter()) {
-            if !v1.nix_eq(v2, vm)? {
-                return Ok(false);
-            }
-        }
+    #[deprecated(note = "callers should avoid constructing from Vec")]
+    pub fn from_vec(vs: Vec<Value>) -> Self {
+        Self(Rc::new(Vector::from_iter(vs)))
+    }
+}
+
+impl IntoIterator for NixList {
+    type Item = Value;
+    type IntoIter = imbl::vector::ConsumingIter<Value>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.into_inner().into_iter()
+    }
+}
+
+impl<'a> IntoIterator for &'a NixList {
+    type Item = &'a Value;
+    type IntoIter = imbl::vector::Iter<'a, Value>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.0.iter()
+    }
+}
+
+impl Index<usize> for NixList {
+    type Output = Value;
 
-        Ok(true)
+    fn index(&self, index: usize) -> &Self::Output {
+        &self.0[index]
     }
 }