Trait FallbackIf 

pub trait FallbackIf<R> {
    // Required method
    fn fallback_if<P, F>(self, predicate: P, alternative: F) -> R
       where P: Into<bool>,
             F: FnOnce() -> R;
}

Fallback to an alternative, if the previous result outcome was a fail, and a predicate is true.

Required Methods

fn fallback_if<P, F>(self, predicate: P, alternative: F) -> R

where P: Into<bool>, F: FnOnce() -> R,

Fallback to an alternative when an outcome is considered a fail and the predicate evaluates to true, otherwise keep the current result.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<T> FallbackIf<Option<T>> for Option<T>

fn fallback_if<P, F>(self, predicate: P, alternative: F) -> Option<T>

where P: Into<bool>, F: FnOnce() -> Option<T>,

impl<T, E> FallbackIf<Result<T, E>> for Result<T, E>

fn fallback_if<P, F>(self, predicate: P, alternative: F) -> Result<T, E>

where P: Into<bool>, F: FnOnce() -> Result<T, E>,

Fallback to an alternative when a result produces an error and the predicate evaluates to true, otherwise keep the current result.

Implementors