1.0.0[−]Primitive Type unit
The () type, sometimes called "unit" or "nil".
The () type has exactly one value (), and is used when there
is no other meaningful value that could be returned. () is most
commonly seen implicitly: functions without a -> ... implicitly
have return type (), that is, these are equivalent:
fn long() -> () {} fn short() {}Run
The semicolon ; can be used to discard the result of an
expression at the end of a block, making the expression (and thus
the block) evaluate to (). For example,
fn returns_i64() -> i64 { 1i64 } fn returns_unit() { 1i64; } let is_i64 = { returns_i64() }; let is_unit = { returns_i64(); };Run
Trait Implementations
impl PartialOrd<()> for ()[src]
fn partial_cmp(&self, &()) -> Option<Ordering>[src]
#[must_use]
fn lt(&self, other: &Rhs) -> bool[src]
This method tests less than (for self and other) and is used by the < operator. Read more
#[must_use]
fn le(&self, other: &Rhs) -> bool[src]
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
#[must_use]
fn gt(&self, other: &Rhs) -> bool[src]
This method tests greater than (for self and other) and is used by the > operator. Read more
#[must_use]
fn ge(&self, other: &Rhs) -> bool[src]
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
impl Ord for ()[src]
fn cmp(&self, _other: &()) -> Ordering[src]
fn max(self, other: Self) -> Self1.21.0[src]
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self1.21.0[src]
Compares and returns the minimum of two values. Read more
impl Eq for ()[src]
impl Debug for ()[src]
impl PartialEq<()> for ()[src]
impl FromIterator<()> for ()1.23.0[src]
Collapses all unit items from an iterator into one.
This is more useful when combined with higher-level abstractions, like
collecting to a Result<(), E> where you only care about errors:
use std::io::*; let data = vec![1, 2, 3, 4, 5]; let res: Result<()> = data.iter() .map(|x| writeln!(stdout(), "{}", x)) .collect(); assert!(res.is_ok());Run
fn from_iter<I>(iter: I) where
I: IntoIterator<Item = ()>, [src]
I: IntoIterator<Item = ()>,
impl Default for ()[src]
impl Hash for ()[src]
fn hash<H>(&self, _state: &mut H) where
H: Hasher, [src]
H: Hasher,
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher, 1.3.0[src]
H: Hasher,
Feeds a slice of this type into the given [Hasher]. Read more
impl Extend<()> for ()1.28.0[src]
fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = ()>, [src]
T: IntoIterator<Item = ()>,