Struct UseContext

pub struct UseContext;

Trait Implementations

impl<Context, SourceError> ErrorRaiser<Context, SourceError> for UseContext

where Context: HasErrorType + CanRaiseError<SourceError>,

Used for injecting external error types into Self::Error.

As an example, if Context: CanRaiseError<ParseIntError>, then we would be able to call Context::raise_error(err) for an error value err: ParseIntError and get back a Context::Error value.

fn raise_error(error: SourceError) -> <Context as HasErrorType>::Error

impl<Context> ErrorTypeProvider<Context> for UseContext

where Context: HasErrorType,

This is used for contexts to declare that they have a unique Self::Error type.

Although it is possible for each context to declare their own associated Error type, doing so may result in having multiple ambiguous Self::Error types, if there are multiple associated types with the same name in different traits.

As a result, it is better for context traits to include HasError as their parent traits, so that multiple traits can all refer to the same abstract Self::Error type.

The Error associated type is also required to implement Debug. This is to allow Self::Error to be used in calls like .unwrap(), as well as for simpler error logging.

More details about how to use HasErrorType is available at https://patterns.contextgeneric.dev/error-handling.html

type Error = <Context as HasErrorType>::Error

impl<Context, Detail> ErrorWrapper<Context, Detail> for UseContext

where Context: HasErrorType + CanWrapError<Detail>,

fn wrap_error( error: <Context as HasErrorType>::Error, detail: Detail, ) -> <Context as HasErrorType>::Error

impl<Context, Tag, Field> FieldGetter<Context, Tag> for UseContext

where Context: HasField<Tag, Value = Field>,

type Value = Field

fn get_field( context: &Context, _tag: PhantomData<Tag>, ) -> &<UseContext as FieldGetter<Context, Tag>>::Value

impl<Context, Tag> ProvideType<Context, Tag> for UseContext

where Context: HasType<Tag>,

type Type = <Context as HasType<Tag>>::Type

impl<Context, SourceError> IsProviderFor<ErrorRaiserComponent, Context, SourceError> for UseContext

where Context: HasErrorType + CanRaiseError<SourceError>,

impl<Context> IsProviderFor<ErrorTypeProviderComponent, Context> for UseContext

where Context: HasErrorType,

impl<Context, Detail> IsProviderFor<ErrorWrapperComponent, Context, Detail> for UseContext

where Context: HasErrorType + CanWrapError<Detail>,

impl<Context, Tag> IsProviderFor<TypeComponent, Context, Tag> for UseContext

where Context: HasType<Tag>,