Use ‘index’ terminology for arena consistently

[rust.git] / lib / arena / src / map.rs

diff --git a/lib/arena/src/map.rs b/lib/arena/src/map.rs
index 5ebaa9b82df86d2c2dc089127679924b3c450a27..d8acfe0518d09adcd4f2fba679f728393db07e85 100644 (file)
--- a/lib/arena/src/map.rs
+++ b/lib/arena/src/map.rs
@@ -2,30 +2,33 @@
 
 use crate::Idx;
 
-/// A map from arena IDs to some other type. Space requirement is O(highest ID).
+/// A map from arena indexes to some other type.
+/// Space requirement is O(highest index).
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct ArenaMap<ID, V> {
+pub struct ArenaMap<IDX, V> {
     v: Vec<Option<V>>,
-    _ty: PhantomData<ID>,
+    _ty: PhantomData<IDX>,
 }
 
 impl<T, V> ArenaMap<Idx<T>, V> {
-    /// Inserts a value associated with a given arena ID into the map.
-    pub fn insert(&mut self, id: Idx<T>, t: V) {
-        let idx = Self::to_idx(id);
+    /// Inserts a value associated with a given arena index into the map.
+    pub fn insert(&mut self, idx: Idx<T>, t: V) {
+        let idx = Self::to_idx(idx);
 
         self.v.resize_with((idx + 1).max(self.v.len()), || None);
         self.v[idx] = Some(t);
     }
 
-    /// Returns a reference to the value associated with the provided ID if it is present.
-    pub fn get(&self, id: Idx<T>) -> Option<&V> {
-        self.v.get(Self::to_idx(id)).and_then(|it| it.as_ref())
+    /// Returns a reference to the value associated with the provided index
+    /// if it is present.
+    pub fn get(&self, idx: Idx<T>) -> Option<&V> {
+        self.v.get(Self::to_idx(idx)).and_then(|it| it.as_ref())
     }
 
-    /// Returns a mutable reference to the value associated with the provided ID if it is present.
-    pub fn get_mut(&mut self, id: Idx<T>) -> Option<&mut V> {
-        self.v.get_mut(Self::to_idx(id)).and_then(|it| it.as_mut())
+    /// Returns a mutable reference to the value associated with the provided index
+    /// if it is present.
+    pub fn get_mut(&mut self, idx: Idx<T>) -> Option<&mut V> {
+        self.v.get_mut(Self::to_idx(idx)).and_then(|it| it.as_mut())
     }
 
     /// Returns an iterator over the values in the map.
@@ -38,13 +41,13 @@ pub fn values_mut(&mut self) -> impl Iterator<Item = &mut V> {
         self.v.iter_mut().filter_map(|o| o.as_mut())
     }
 
-    /// Returns an iterator over the arena IDs and values in the map.
+    /// Returns an iterator over the arena indexes and values in the map.
     pub fn iter(&self) -> impl Iterator<Item = (Idx<T>, &V)> {
         self.v.iter().enumerate().filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_ref()?)))
     }
 
-    fn to_idx(id: Idx<T>) -> usize {
-        u32::from(id.into_raw()) as usize
+    fn to_idx(idx: Idx<T>) -> usize {
+        u32::from(idx.into_raw()) as usize
     }
 
     fn from_idx(idx: usize) -> Idx<T> {
@@ -54,8 +57,8 @@ fn from_idx(idx: usize) -> Idx<T> {
 
 impl<T, V> std::ops::Index<Idx<V>> for ArenaMap<Idx<V>, T> {
     type Output = T;
-    fn index(&self, id: Idx<V>) -> &T {
-        self.v[Self::to_idx(id)].as_ref().unwrap()
+    fn index(&self, idx: Idx<V>) -> &T {
+        self.v[Self::to_idx(idx)].as_ref().unwrap()
     }
 }