Struct PieView 

pub struct PieView<'a, T> { /* private fields */ }

A lightweight, temporary view into a PieList that borrows the backing ElemPool.

PieView bundles the list handle and the data pool together into a single, lightweight struct. This enables standard Rust traits like IntoIterator, Debug, and PartialEq, which require access to the data without passing a secondary pool argument.

Since PieView only holds shared references, it implements Copy and Clone regardless of whether the underlying type T implements them.

Examples

Printing (Debug)

use pie_core::{ElemPool, PieList};

let mut pool = ElemPool::new();
let mut list = PieList::new(&mut pool);
list.push_back(10, &mut pool).unwrap();
list.push_back(20, &mut pool).unwrap();

let view = list.view(&pool);
assert_eq!(format!("{:?}", view), "[10, 20]");

list.clear(&mut pool);

Iterating

let view = list.view(&pool);

let mut sum = 0;
for &item in view {
    sum += item;
}
assert_eq!(sum, 3);

Equality

You can compare two lists for equality, even if they live in different pools.

let mut pool1 = ElemPool::new();
let mut list1 = PieList::new(&mut pool1);
list1.push_back("apple", &mut pool1).unwrap();

let mut pool2 = ElemPool::new();
let mut list2 = PieList::new(&mut pool2);
list2.push_back("apple", &mut pool2).unwrap();

// Compare views
assert_eq!(list1.view(&pool1), list2.view(&pool2));

Implementations

impl<'a, T> PieView<'a, T>

pub fn new(list: &'a PieList<T>, pool: &'a ElemPool<T>) -> Self

Creates a new view for the given list using the data in pool.

It is often more ergonomic to use PieList::view instead.

pub fn len(&self) -> usize

Returns the number of elements in the list.

Example

let view = list.view(&pool);
assert_eq!(view.len(), 0);

pub fn is_empty(&self) -> bool

Returns true if the list is empty.

Example

let view = list.view(&pool);
assert!(view.is_empty());

pub fn front(&self) -> Option<&T>

Returns a reference to the front element.

Example

let view = list.view(&pool);
assert_eq!(view.front(), Some(&10));

pub fn back(&self) -> Option<&T>

Returns a reference to the back element.

Example

let view = list.view(&pool);
assert_eq!(view.back(), Some(&10));

pub fn iter(&self) -> Iter<'a, T>

Creates an iterator over the list’s elements.

Example

let view = list.view(&pool);
let vec: Vec<_> = view.iter().copied().collect();
assert_eq!(vec, vec![1, 2]);

Trait Implementations

impl<'a, T> Clone for PieView<'a, T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a, T: Debug> Debug for PieView<'a, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a, T> IntoIterator for PieView<'a, T>

type Item = &'a T

The type of the elements being iterated over.

type IntoIter = Iter<'a, T>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a, T: Ord> Ord for PieView<'a, T>

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<'a, T: PartialEq> PartialEq for PieView<'a, T>

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, T: PartialOrd> PartialOrd for PieView<'a, T>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a, T> Copy for PieView<'a, T>

impl<'a, T: Eq> Eq for PieView<'a, T>