Trait mini_haskell::utils::control::Maybe

pub trait Maybe {
    type Just;
    fn just(x: Self::Just) -> Self;
    fn is_just(&self) -> bool;
    fn into_optional(self) -> Option<Self::Just>;

    fn is_nothing(&self) -> bool { ... }
}

Named after Maybe, Just, and Nothing from Haskell. Use this for success/failure semantics, since Either is used to model the control flow.

Associated Types

type Just

The success type in a Just.

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Required methods

fn just(x: Self::Just) -> Self

Construct a success.

fn is_just(&self) -> bool

Check whether it is a success.

fn into_optional(self) -> Option<Self::Just>

Convert into an Option.

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Provided methods

fn is_nothing(&self) -> bool

Check whether it is a failure.

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Implementations on Foreign Types

impl<T> Maybe for Option<T>

type Just = T

fn just(x: T) -> Self

fn is_just(&self) -> bool

fn into_optional(self) -> Option<Self::Just>

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

type Just = T

fn just(x: T) -> Self

fn is_just(&self) -> bool

fn into_optional(self) -> Option<T>

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Implementors

impl<T, E, M> Maybe for Result3<T, E, M>

type Just = T

fn just(x: T) -> Self

fn is_just(&self) -> bool

fn into_optional(self) -> Option<Self::Just>

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