Trait DefensiveResult

pub trait DefensiveResult<T, E> {
    // Required methods
    fn defensive_map_err<F, O>(self, o: O) -> Result<T, F>
       where O: FnOnce(E) -> F;
    fn defensive_map_or_else<U, D, F>(self, default: D, f: F) -> U
       where D: FnOnce(E) -> U,
             F: FnOnce(T) -> U;
    fn defensive_ok(self) -> Option<T>;
    fn defensive_map<U, F>(self, f: F) -> Result<U, E>
       where F: FnOnce(T) -> U;
}

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

Required Methods

fn defensive_map_err<F, O>(self, o: O) -> Result<T, F>

where O: FnOnce(E) -> F,

Defensively map the error into another return type, but you are really sure that this conversion should never be needed.

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

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

Defensively map and unpack the value to something else (U), or call the default callback if Err, which should never happen.

fn defensive_ok(self) -> Option<T>

Defensively transform this result into an option, discarding the Err variant if it happens, which should never happen.

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

where F: FnOnce(T) -> U,

Exactly the same as map, but it prints the appropriate warnings if the value being mapped is Err.

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, E> DefensiveResult<T, E> for Result<T, E>

where E: Debug,

fn defensive_map_err<F, O>(self, o: O) -> Result<T, F>

where O: FnOnce(E) -> F,

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

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

fn defensive_ok(self) -> Option<T>

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

where F: FnOnce(T) -> U,

Implementors