Primitive Type bool

The boolean type.

The bool represents a value, which could only be either true or false.

Basic usage

bool implements various traits, such as BitAnd, BitOr, Not, etc., which allow us to perform boolean operations using &, | and !.

[if] always demands a bool value. assert!, being an important macro in testing, checks whether an expression returns true.

fn main() { let bool_val = true & false | false; assert!(!bool_val); }

let bool_val = true & false | false;
assert!(!bool_val);

Examples

A trivial example of the usage of bool,

fn main() { let praise_the_borrow_checker = true; // using the `if` conditional if praise_the_borrow_checker { println!("oh, yeah!"); } else { println!("what?!!"); } // ... or, a match pattern match praise_the_borrow_checker { true => println!("keep praising!"), false => println!("you should praise!"), } }

let praise_the_borrow_checker = true;

// using the `if` conditional
if praise_the_borrow_checker {
    println!("oh, yeah!");
} else {
    println!("what?!!");
}

// ... or, a match pattern
match praise_the_borrow_checker {
    true => println!("keep praising!"),
    false => println!("you should praise!"),
}

Also, since bool implements the Copy trait, we don't have to worry about the move semantics (just like the integer and float primitives).

Trait Implementations

impl Not for bool

type Output = bool

The resulting type after applying the ! operator

fn not(self) -> bool

The method for the unary ! operator

impl<'a> Not for &'a bool

type Output = bool::Output

The resulting type after applying the ! operator

fn not(self) -> bool::Output

The method for the unary ! operator

impl BitAnd<bool> for bool

type Output = bool

The resulting type after applying the & operator

fn bitand(self, rhs: bool) -> bool

The method for the & operator

impl<'a> BitAnd<bool> for &'a bool

type Output = bool::Output

The resulting type after applying the & operator

fn bitand(self, other: bool) -> bool::Output

The method for the & operator

impl<'a> BitAnd<&'a bool> for bool

type Output = bool::Output

The resulting type after applying the & operator

fn bitand(self, other: &'a bool) -> bool::Output

The method for the & operator

impl<'a, 'b> BitAnd<&'a bool> for &'b bool

type Output = bool::Output

The resulting type after applying the & operator

fn bitand(self, other: &'a bool) -> bool::Output

The method for the & operator

impl BitOr<bool> for bool

type Output = bool

The resulting type after applying the | operator

fn bitor(self, rhs: bool) -> bool

The method for the | operator

impl<'a> BitOr<bool> for &'a bool

type Output = bool::Output

The resulting type after applying the | operator

fn bitor(self, other: bool) -> bool::Output

The method for the | operator

impl<'a> BitOr<&'a bool> for bool

type Output = bool::Output

The resulting type after applying the | operator

fn bitor(self, other: &'a bool) -> bool::Output

The method for the | operator

impl<'a, 'b> BitOr<&'a bool> for &'b bool

type Output = bool::Output

The resulting type after applying the | operator

fn bitor(self, other: &'a bool) -> bool::Output

The method for the | operator

impl BitXor<bool> for bool

type Output = bool

The resulting type after applying the ^ operator

fn bitxor(self, other: bool) -> bool

The method for the ^ operator

impl<'a> BitXor<bool> for &'a bool

type Output = bool::Output

The resulting type after applying the ^ operator

fn bitxor(self, other: bool) -> bool::Output

The method for the ^ operator

impl<'a> BitXor<&'a bool> for bool

type Output = bool::Output

The resulting type after applying the ^ operator

fn bitxor(self, other: &'a bool) -> bool::Output

The method for the ^ operator

impl<'a, 'b> BitXor<&'a bool> for &'b bool

type Output = bool::Output

The resulting type after applying the ^ operator

fn bitxor(self, other: &'a bool) -> bool::Output

The method for the ^ operator

impl BitAndAssign<bool> for bool

fn bitand_assign(&mut self, other: bool)

The method for the & operator

impl BitOrAssign<bool> for bool

fn bitor_assign(&mut self, other: bool)

The method for the |= operator

impl BitXorAssign<bool> for bool

fn bitxor_assign(&mut self, other: bool)

The method for the ^= operator

impl PartialEq<bool> for bool

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

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

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

This method tests for !=.

impl Eq for bool

impl PartialOrd<bool> for bool

fn partial_cmp(&self, other: &bool) -> 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 Ord for bool

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

This method returns an Ordering between self and other.

impl Clone for bool

fn clone(&self) -> bool

Returns a deep copy of the value.

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

Performs copy-assignment from source.

impl Default for bool

fn default() -> bool

Returns the "default value" for a type.

impl FromStr for bool

type Err = ParseBoolError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<bool, ParseBoolError>

Parse a bool from a string.

Yields a Result<bool, ParseBoolError>, because s may or may not actually be parseable.

Examples

fn main() { use std::str::FromStr; assert_eq!(FromStr::from_str("true"), Ok(true)); assert_eq!(FromStr::from_str("false"), Ok(false)); assert!(<bool as FromStr>::from_str("not even a boolean").is_err()); }

use std::str::FromStr;

assert_eq!(FromStr::from_str("true"), Ok(true));
assert_eq!(FromStr::from_str("false"), Ok(false));
assert!(<bool as FromStr>::from_str("not even a boolean").is_err());

Note, in many cases, the .parse() method on str is more proper.

fn main() { assert_eq!("true".parse(), Ok(true)); assert_eq!("false".parse(), Ok(false)); assert!("not even a boolean".parse::<bool>().is_err()); }

assert_eq!("true".parse(), Ok(true));
assert_eq!("false".parse(), Ok(false));
assert!("not even a boolean".parse::<bool>().is_err());

impl Hash for bool

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

Feeds this value into the state given, updating the hasher as necessary.

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

Feeds a slice of this type into the state provided.

impl Debug for bool

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

Formats the value using the given formatter.

impl Display for bool

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

Formats the value using the given formatter.