Trait Predicate 

pub trait Predicate<T: ?Sized> {
    // Required methods
    fn check(value: &T) -> bool;
    fn expect(formatter: &mut Formatter<'_>) -> Result;
    fn expect_code(formatter: &mut Formatter<'_>) -> Result;

    // Provided method
    fn check_value(value: T) -> bool
       where T: Sized { ... }
}

Represents predicates over values of type T.

Required Methods

fn check(value: &T) -> bool

Checks the given reference to value of type T.

Returns true if the predicate is satisfied by this value, false otherwise.

fn expect(formatter: &mut Formatter<'_>) -> Result

Formats the expectation of this predicate into the given formatter.

Errors

Returns fmt::Error in case formatting fails.

fn expect_code(formatter: &mut Formatter<'_>) -> Result

Formats the expectation code of this predicate into the given formatter.

Errors

Returns fmt::Error in case formatting fails.

Provided Methods

fn check_value(value: T) -> bool

where T: Sized,

Checks the given value of type T.

Returns true if the predicate is satisfied by this value, false otherwise.

The default implementation simply calls check with value reference.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<T: ?Sized, P: Predicate<T> + ?Sized, Q: Predicate<T> + ?Sized> Predicate<T> for And<P, Q>

impl<T: ?Sized, P: Predicate<T> + ?Sized, Q: Predicate<T> + ?Sized> Predicate<T> for Or<P, Q>

impl<T: ?Sized, P: Predicate<T> + ?Sized, Q: Predicate<T> + ?Sized> Predicate<T> for Xor<P, Q>

impl<T: ?Sized, P: Predicate<T> + ?Sized> Predicate<T> for Not<P>

impl<T: ?Sized> Predicate<T> for False

impl<T: ?Sized> Predicate<T> for True