Primitive Type bool

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The boolean type.

The bool represents a value, which could only be either true or false. If you cast a bool into an integer, true will be 1 and false will be 0.

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.

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

Examples

A trivial example of the usage of bool,

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).

Now an example of bool cast to integer type:

assert_eq!(true as i32, 1);
assert_eq!(false as i32, 0);

Trait Implementations

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

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type Output = <bool as BitAnd<bool>>::Output

The resulting type after applying the & operator.

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

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Performs the & operation.

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

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type Output = <bool as BitAnd<bool>>::Output

The resulting type after applying the & operator.

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

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Performs the & operation.

impl BitAnd<bool> for bool

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type Output = bool

The resulting type after applying the & operator.

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

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Performs the & operation.

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

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type Output = <bool as BitAnd<bool>>::Output

The resulting type after applying the & operator.

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

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Performs the & operation.

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

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fn bitor_assign(&mut self, other: &'a bool)

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Performs the |= operation.

impl BitOrAssign<bool> for bool

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fn bitor_assign(&mut self, other: bool)

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Performs the |= operation.

impl Debug for bool

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

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Formats the value using the given formatter.

impl Ord for bool

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

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This method returns an Ordering between self and other.

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

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Compares and returns the maximum of two values.

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

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Compares and returns the minimum of two values.

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

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type Output = <bool as BitXor<bool>>::Output

The resulting type after applying the ^ operator.

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

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Performs the ^ operation.

impl BitXor<bool> for bool

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type Output = bool

The resulting type after applying the ^ operator.

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

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Performs the ^ operation.

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

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type Output = <bool as BitXor<bool>>::Output

The resulting type after applying the ^ operator.

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

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Performs the ^ operation.

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

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type Output = <bool as BitXor<bool>>::Output

The resulting type after applying the ^ operator.

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

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Performs the ^ operation.

impl Hash for bool

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

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Feeds this value into the given [Hasher].

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

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Feeds a slice of this type into the given [Hasher].

impl PartialEq<bool> for bool

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

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

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

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This method tests for !=.

impl<'a> Not for &'a bool

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type Output = <bool as Not>::Output

The resulting type after applying the ! operator.

fn not(self) -> <bool as Not>::Output

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Performs the unary ! operation.

impl Not for bool

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type Output = bool

The resulting type after applying the ! operator.

fn not(self) -> bool

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Performs the unary ! operation.

impl FromStr for bool

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type Err = ParseBoolError

The associated error which can be returned from parsing.

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

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Parse a bool from a string.

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

Examples

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.

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

impl Display for bool

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

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Formats the value using the given formatter.

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

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fn bitxor_assign(&mut self, other: &'a bool)

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Performs the ^= operation.

impl BitXorAssign<bool> for bool

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fn bitxor_assign(&mut self, other: bool)

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Performs the ^= operation.

impl BitAndAssign<bool> for bool

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fn bitand_assign(&mut self, other: bool)

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Performs the &= operation.

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

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fn bitand_assign(&mut self, other: &'a bool)

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Performs the &= operation.

impl BitOr<bool> for bool

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type Output = bool

The resulting type after applying the | operator.

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

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Performs the | operation.

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

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type Output = <bool as BitOr<bool>>::Output

The resulting type after applying the | operator.

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

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Performs the | operation.

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

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type Output = <bool as BitOr<bool>>::Output

The resulting type after applying the | operator.

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

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Performs the | operation.

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

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type Output = <bool as BitOr<bool>>::Output

The resulting type after applying the | operator.

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

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Performs the | operation.

impl Default for bool

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fn default() -> bool

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Returns the default value of false

impl PartialOrd<bool> for bool

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

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

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

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

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

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

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

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

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

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

impl Eq for bool