Trait CheckedIndex 

pub trait CheckedIndex<T>:
    From<T>
    + Into<Option<T>>
    + Add<Output = Self>
    + Add<T, Output = Self>
    + Sub<Output = Self>
    + Sub<T, Output = Self>
    + Mul<T, Output = Self>
    + Div<T, Output = Self>
    + Rem<T, Output = Self> {
    // Required methods
    fn invalid() -> Self;
    fn is_valid(&self) -> bool;
    fn unwrap(self) -> T;
    fn expect(self, msg: &str) -> T;
    fn map<F: FnOnce(T) -> T>(self, f: F) -> Self;
    fn map_or<U, F: FnOnce(T) -> U>(self, default: U, f: F) -> U;
    fn into_inner(self) -> T;
}

A trait that defines what it means for an index to be a checked index. In other words implementers are indices that are checked for validity in some way.

Required Methods

fn invalid() -> Self

Construct an invalid index.

fn is_valid(&self) -> bool

Check if the index is valid.

fn unwrap(self) -> T

Convert the index into its underlying integer type. Panic if index is invalid.

fn expect(self, msg: &str) -> T

Convert the index into its underlying integer type. In case of failure, report the given message.

fn map<F: FnOnce(T) -> T>(self, f: F) -> Self

Map the underlying integer type. This allows restricting operations to valid indices only.

fn map_or<U, F: FnOnce(T) -> U>(self, default: U, f: F) -> U

Map the underlying integer type. If the index is invalid, output the provided default.

fn into_inner(self) -> T

Produce the raw inner type without checking.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl CheckedIndex<usize> for Index