Trait TapFallible

pub trait TapFallible
where
    Self: Sized,
{
    type Ok: ?Sized;
    type Err: ?Sized;

    // Required methods
    fn tap_ok(self, func: impl FnOnce(&Self::Ok)) -> Self;
    fn tap_ok_mut(self, func: impl FnOnce(&mut Self::Ok)) -> Self;
    fn tap_err(self, func: impl FnOnce(&Self::Err)) -> Self;
    fn tap_err_mut(self, func: impl FnOnce(&mut Self::Err)) -> Self;

    // Provided methods
    fn tap_ok_dbg(self, func: impl FnOnce(&Self::Ok)) -> Self { ... }
    fn tap_ok_mut_dbg(self, func: impl FnOnce(&mut Self::Ok)) -> Self { ... }
    fn tap_err_dbg(self, func: impl FnOnce(&Self::Err)) -> Self { ... }
    fn tap_err_mut_dbg(self, func: impl FnOnce(&mut Self::Err)) -> Self { ... }
}

Fallible tapping, conditional on the optional success of an expression.

This trait is intended for use on types that express the concept of “fallible presence”, primarily the Result monad. It provides taps that inspect the container to determine if the effect function should execute or not.

Note: This trait would ideally be implemented as a blanket over all std::ops::Try implementors. When Try stabilizes, this crate can be updated to do so.

Required Associated Types

type Ok: ?Sized

The interior type used to indicate a successful construction.

type Err: ?Sized

The interior type used to indicate a failed construction.

Required Methods

fn tap_ok(self, func: impl FnOnce(&Self::Ok)) -> Self

Immutably accesses an interior success value.

This function is identical to Tap::tap, except that it is required to check the implementing container for value success before running. Implementors must not run the effect function if the container is marked as being a failure.

fn tap_ok_mut(self, func: impl FnOnce(&mut Self::Ok)) -> Self

Mutably accesses an interior success value.

This function is identical to Tap::tap_mut, except that it is required to check the implementing container for value success before running. Implementors must not run the effect function if the container is marked as being a failure.

fn tap_err(self, func: impl FnOnce(&Self::Err)) -> Self

Immutably accesses an interior failure value.

This function is identical to Tap::tap, except that it is required to check the implementing container for value failure before running. Implementors must not run the effect function if the container is marked as being a success.

fn tap_err_mut(self, func: impl FnOnce(&mut Self::Err)) -> Self

Mutably accesses an interior failure value.

This function is identical to Tap::tap_mut, except that it is required to check the implementing container for value failure before running. Implementors must not run the effect function if the container is marked as being a success.

Provided Methods

fn tap_ok_dbg(self, func: impl FnOnce(&Self::Ok)) -> Self

Calls .tap_ok() only in debug builds, and is erased in release builds.

fn tap_ok_mut_dbg(self, func: impl FnOnce(&mut Self::Ok)) -> Self

Calls .tap_ok_mut() only in debug builds, and is erased in release builds.

fn tap_err_dbg(self, func: impl FnOnce(&Self::Err)) -> Self

Calls .tap_err() only in debug builds, and is erased in release builds.

fn tap_err_mut_dbg(self, func: impl FnOnce(&mut Self::Err)) -> Self

Calls .tap_err_mut() only in debug builds, and is erased in release builds.

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> TapFallible for Result<T, E>

type Ok = T

type Err = E

fn tap_ok(self, func: impl FnOnce(&T)) -> Self

fn tap_ok_mut(self, func: impl FnOnce(&mut T)) -> Self

fn tap_err(self, func: impl FnOnce(&E)) -> Self

fn tap_err_mut(self, func: impl FnOnce(&mut E)) -> Self

Implementors