Struct uid::Id

pub struct Id<T>where
    T: Copy,{ /* private fields */ }

A struct representing IDs usable for various purposes.

Note that Rust only truly provides the implementations of the various traits we derive from when T also provides them. Note furthermore that we want all ID objects to be lightweight and, hence, require the implementation of Copy for T (which we do not for all the other, optional, traits).

Examples

A commonly seen pattern for creating of a type Id that is unique may look as follows:

use uid::Id as IdT;

#[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
struct T(());

type Id = IdT<T>;

let id1 = Id::new();
let id2 = Id::new();

assert_ne!(id1, id2)

In this example the type T is just an arbitrary type, but it allows us to create distinct ID types. For example, when another ID type is required for a different purpose, that can be easily created:

#[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
struct U(());

type Key = IdT<U>;

// `Key` and `Id` are fundamentally different types, with no
// allowed interaction between each other. That is, Rust's type
// system will prevent accidental usage of one in place of the
// other. The same can be said about the relationship to built-in
// numeric types such as `usize` or `u64`.

Implementations

impl<T> Id<T>where
    T: Copy,

pub fn new() -> Self

Create a new unique Id.

pub fn get(&self) -> usize

Retrieve the underlying usize value.

Trait Implementations

impl<T> Clone for Id<T>where
    T: Copy + Clone,

fn clone(&self) -> Id<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Id<T>where
    T: Copy,

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

Formats the value using the given formatter.

impl<T> Display for Id<T>where
    T: Copy,

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

Format the Id into the given formatter.

impl<T> Hash for Id<T>where
    T: Copy + Hash,

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T> Ord for Id<T>where
    T: Copy + Ord,

fn cmp(&self, other: &Id<T>) -> Ordering

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval.

impl<T> PartialEq<Id<T>> for Id<T>where
    T: Copy + PartialEq,

fn eq(&self, other: &Id<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<T> PartialOrd<Id<T>> for Id<T>where
    T: Copy + PartialOrd,

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

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

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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl<T> Copy for Id<T>where
    T: Copy + Copy,

impl<T> Eq for Id<T>where
    T: Copy + Eq,

impl<T> StructuralEq for Id<T>where
    T: Copy,

impl<T> StructuralPartialEq for Id<T>where
    T: Copy,