Trait DefensiveOption

pub trait DefensiveOption<T> {
    // Required methods
    fn defensive_map_or_else<U, D, F>(self, default: D, f: F) -> U
       where D: FnOnce() -> U,
             F: FnOnce(T) -> U;
    fn defensive_ok_or_else<E, F>(self, err: F) -> Result<T, E>
       where E: Debug,
             F: FnOnce() -> E;
    fn defensive_ok_or<E>(self, err: E) -> Result<T, E>
       where E: Debug;
    fn defensive_map<U, F>(self, f: F) -> Option<U>
       where F: FnOnce(T) -> U;
}

Subset of methods similar to Defensive that can only work for a Option.

Required Methods

fn defensive_map_or_else<U, D, F>(self, default: D, f: F) -> U

where D: FnOnce() -> U, F: FnOnce(T) -> U,

Potentially map and unpack the value to something else (U), or call the default callback if None, which should never happen.

fn defensive_ok_or_else<E, F>(self, err: F) -> Result<T, E>

where E: Debug, F: FnOnce() -> E,

Defensively transform this option to a result, mapping None to the return value of an error closure.

fn defensive_ok_or<E>(self, err: E) -> Result<T, E>

where E: Debug,

Defensively transform this option to a result, mapping None to a default value.

fn defensive_map<U, F>(self, f: F) -> Option<U>

where F: FnOnce(T) -> U,

Exactly the same as map, but it prints the appropriate warnings if the value being mapped is None.

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> DefensiveOption<T> for Option<T>

fn defensive_map_or_else<U, D, F>(self, default: D, f: F) -> U

where D: FnOnce() -> U, F: FnOnce(T) -> U,

fn defensive_ok_or_else<E, F>(self, err: F) -> Result<T, E>

where E: Debug, F: FnOnce() -> E,

fn defensive_ok_or<E>(self, err: E) -> Result<T, E>

where E: Debug,

fn defensive_map<U, F>(self, f: F) -> Option<U>

where F: FnOnce(T) -> U,

Implementors