Trait predicates::PredicateBoxExt

source · 
pub trait PredicateBoxExt<Item: ?Sized>where
    Self: Predicate<Item>,{
    fn boxed(self) -> BoxPredicate<Item>
    where
        Self: Sized + Send + Sync + 'static,
    { ... }
}
Expand description

Predicate extension for boxing a Predicate.

Provided Methods§

Returns a BoxPredicate wrapper around this Predicate type.

Returns a BoxPredicate wrapper around this Predicate type. The BoxPredicate` type has a number of useful properties:

  • It stores the inner predicate as a trait object, so the type of BoxPredicate will always be the same even if steps are added or removed from the predicate.
  • It is a common type, allowing it to be stored in vectors or other collection types.
  • It implements Debug and Display.
Examples
use predicates::prelude::*;

let predicates = vec![
    predicate::always().boxed(),
    predicate::never().boxed(),
];
assert_eq!(true, predicates[0].eval(&4));
assert_eq!(false, predicates[1].eval(&4));

Implementors§