Trait predicates_core::Predicate[−][src]

pub trait Predicate<Item: ?Sized>: PredicateReflection {
    fn eval(&self, variable: &Item) -> bool;

    fn find_case<'a>(
        &'a self, 
        expected: bool, 
        variable: &Item
    ) -> Option<Case<'a>> { ... }
}

Trait for generically evaluating a type against a dynamically created predicate function.

The exact meaning of eval depends on the situation, but will usually mean that the evaluated item is in some sort of pre-defined set. This is different from Ord and Eq in that an item will almost never be the same type as the implementing Predicate type.

Required methods

fn eval(&self, variable: &Item) -> bool[src]

Execute this Predicate against variable, returning the resulting boolean.

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Provided methods

fn find_case<'a>(&'a self, expected: bool, variable: &Item) -> Option<Case<'a>>[src]

Find a case that proves this predicate as expected when run against variable.

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Implementors

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