Trait Arena 

pub trait Arena: Allocator {
    // Required methods
    fn alloc<T>(&self, value: T) -> &mut T;
    fn alloc_with<T>(&self, f: impl FnOnce() -> T) -> &mut T;
    fn alloc_str(&self, src: &str) -> &mut str;
    fn alloc_fmt(&self, arguments: Arguments<'_>) -> &mut str;
    fn alloc_slice_copy<T>(&self, src: &[T]) -> &mut [T]
       where T: Copy;
    fn alloc_slice_clone<T>(&self, src: &[T]) -> &mut [T]
       where T: Clone;
    fn alloc_slice_fill_copy<T>(&self, len: usize, value: T) -> &mut [T]
       where T: Copy;
    fn alloc_slice_fill_clone<T>(&self, len: usize, value: &T) -> &mut [T]
       where T: Clone;
    fn alloc_slice_fill_with<T>(
        &self,
        len: usize,
        f: impl FnMut(usize) -> T,
    ) -> &mut [T];
    fn alloc_slice_fill_default<T>(&self, len: usize) -> &mut [T]
       where T: Default;
    fn alloc_slice_fill_iter<T>(
        &self,
        iter: impl IntoIterator<Item = T>,
    ) -> &mut [T];
}

Ergonomic, bumpalo-style allocation on top of any Allocator.

Every method returns a reference (or mutable slice) tied to the borrow of the arena, so the allocation escapes the call and lives for the arena’s lifetime. Implemented for every Allocator (including the three arenas and shared references to them) via a blanket impl.

Required Methods

fn alloc<T>(&self, value: T) -> &mut T

Allocates value and returns a unique reference to it.

fn alloc_with<T>(&self, f: impl FnOnce() -> T) -> &mut T

Allocates the result of f, evaluated directly into the arena slot.

fn alloc_str(&self, src: &str) -> &mut str

Copies src into the arena and returns the copy.

fn alloc_fmt(&self, arguments: Arguments<'_>) -> &mut str

Formats arguments directly into the arena and returns the resulting string.

The arena-equivalent of format!, with no intermediate global allocation:

use mago_allocator::prelude::*;

let arena = LocalArena::new();
let greeting = arena.alloc_fmt(format_args!("{}-{}", "v", 2));
assert_eq!(greeting, "v-2");

fn alloc_slice_copy<T>(&self, src: &[T]) -> &mut [T]

where T: Copy,

Copies a slice of Copy values into the arena.

fn alloc_slice_clone<T>(&self, src: &[T]) -> &mut [T]

where T: Clone,

Clones a slice of Clone values into the arena.

fn alloc_slice_fill_copy<T>(&self, len: usize, value: T) -> &mut [T]

where T: Copy,

Allocates len copies of value.

fn alloc_slice_fill_clone<T>(&self, len: usize, value: &T) -> &mut [T]

where T: Clone,

Allocates len clones of value.

fn alloc_slice_fill_with<T>( &self, len: usize, f: impl FnMut(usize) -> T, ) -> &mut [T]

Allocates len elements, each produced by f(index).

fn alloc_slice_fill_default<T>(&self, len: usize) -> &mut [T]

where T: Default,

Allocates len default-constructed elements.

fn alloc_slice_fill_iter<T>( &self, iter: impl IntoIterator<Item = T>, ) -> &mut [T]

Collects iter into the arena and returns the resulting slice.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<A: Allocator + ?Sized> Arena for A