Struct cop::Symbol

pub struct Symbol<'s>(/* private fields */);

Shared string with fast cloning, hashing, and equality check.

Cloning, hashing, and equality checking is performed on the address of the pointer, making them constant-time operations.

Note that two different symbols pointing to equivalent strings are not equal, as well as their hashes:

let h1 = String::from("Hello");
let h2 = String::from("Hello");
let wl = String::from("World");
let s1 = Symbol::new(&h1);
let s2 = Symbol::new(&h2);
let s3 = Symbol::new(&wl);

assert_eq!(s1, s1);
assert_eq!(s1, s1.clone());
assert_ne!(s1, s2);
assert_ne!(s1, s3);

let hash = |s: Symbol| -> u64 {
    let mut hasher = DefaultHasher::new();
    s.hash(&mut hasher);
    hasher.finish()
};

assert_eq!(hash(s1), hash(s1.clone()));
assert_ne!(hash(s1), hash(s2));

Implementations

impl<'s> Symbol<'s>

pub fn new(s: &'s str) -> Self

Create a new symbol with given name.

Trait Implementations

impl<'s> Clone for Symbol<'s>

fn clone(&self) -> Symbol<'s>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<'s> Debug for Symbol<'s>

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

Formats the value using the given formatter.

impl<'s> Display for Symbol<'s>

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

Formats the value using the given formatter.

impl<'s> Hash for Symbol<'s>

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<'s> PartialEq<Symbol<'s>> for Symbol<'s>

fn eq(&self, other: &Self) -> 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<'s> Copy for Symbol<'s>

impl<'s> Eq for Symbol<'s>