diff options
Diffstat (limited to 'compiler/rustc_index/src')
| -rw-r--r-- | compiler/rustc_index/src/vec.rs | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/compiler/rustc_index/src/vec.rs b/compiler/rustc_index/src/vec.rs index 66c5cc774b2..3148b054790 100644 --- a/compiler/rustc_index/src/vec.rs +++ b/compiler/rustc_index/src/vec.rs @@ -12,10 +12,26 @@ use std::vec; use crate::{Idx, IndexSlice}; /// An owned contiguous collection of `T`s, indexed by `I` rather than by `usize`. +/// Its purpose is to avoid mixing indexes. /// /// While it's possible to use `u32` or `usize` directly for `I`, /// you almost certainly want to use a [`newtype_index!`]-generated type instead. /// +/// This allows to index the IndexVec with the new index type: +/// +/// ``` +/// use crate as rustc_index; +/// use rustc_index::{IndexVec, newtype_index}; +/// +/// newtype_index! { +/// pub struct MyIdx {} +/// } +/// +/// let my_index_vec: IndexVec<MyIdx, u32> = IndexVec::from_raw(vec![0,1,2,3]); +/// let idx: MyIdx = MyIdx::from_u32(2); +/// assert_eq!(my_index_vec[idx], 2); +/// ``` +/// /// [`newtype_index!`]: ../macro.newtype_index.html #[derive(Clone, PartialEq, Eq, Hash)] #[repr(transparent)] @@ -25,11 +41,13 @@ pub struct IndexVec<I: Idx, T> { } impl<I: Idx, T> IndexVec<I, T> { + /// Constructs a new, empty `IndexVec<I, T>`. #[inline] pub const fn new() -> Self { IndexVec::from_raw(Vec::new()) } + /// Constructs a new `IndexVec<I, T>` from a `Vec<T>` #[inline] pub const fn from_raw(raw: Vec<T>) -> Self { IndexVec { raw, _marker: PhantomData } @@ -59,6 +77,7 @@ impl<I: Idx, T> IndexVec<I, T> { IndexVec::from_raw(vec![elem; universe.len()]) } + /// Creates a new `IndexVec` with n copies of `elem` #[inline] pub fn from_elem_n(elem: T, n: usize) -> Self where |