Struct WhenProvider

pub struct WhenProvider<L, P, Cx, Out> { /* private fields */ }

Return type of when_provider().

Example

use dynamic_provider::{when_provider, ProvideRef};

dynamic_provider::define_tag! {
    tag Details: for<'x> (&'x str, &'x str);
}

fn get_details(provider: &dyn ProvideRef) -> String {
    when_provider(provider)
        .has_value::<String>(|s| s)
        .has_ref::<str>(|s| s.into())
        .has::<Details>((), |(a, b)| format!("{a}, {b}"))
        .or_else(|_| "unknown".into())
}

Implementations

impl<L: Lt, P: Provide<L>, Out> WhenProvider<L, P, NoContext, Out>

pub fn finish(self) -> Result<Out, P>

Returns the output of the successful request if there is one, or an Err containing the original provider.

pub fn or_else(self, f: impl FnOnce(P) -> Out) -> Out

Returns the output of the successful request if there is one, or the return value of the given function that accepts the original provider.

pub fn with<Cx>(self, context: Cx) -> WhenProvider<L, P, HasContext<Cx>, Out>

Adds a context value to all subsequent request handlers, which will be passed as the second callback parameter.

pub fn has<Tag: TagFor<L>>( self, arg: Tag::ArgValue, transform: impl FnOnce(Tag::Value) -> Out, ) -> Self

Handle the case where the type marked by Tag is supplied by the provider.

pub fn has_value<T: 'static>(self, transform: impl FnOnce(T) -> Out) -> Self

Handle the case where a value of type T, marked by Value<T>, is supplied by the provider.

impl<'x, L: Lt, P: Provide<LtList<'x, L>>, Out> WhenProvider<LtList<'x, L>, P, NoContext, Out>

pub fn has_ref<T: 'static + ?Sized>( self, transform: impl FnOnce(&'x T) -> Out, ) -> Self

Handle the case where a shared reference to a value of type T, marked by Ref<Value<T>>, is supplied by the provider.

pub fn has_mut<T: 'static + ?Sized>( self, transform: impl FnOnce(&'x mut T) -> Out, ) -> Self

Handle the case where a unique reference to a value of type T, marked by Mut<Value<T>>, is supplied by the provider.

impl<L: Lt, P: Provide<L>, Cx, Out> WhenProvider<L, P, HasContext<Cx>, Out>

pub fn finish(self) -> Result<Out, (P, Cx)>

Returns the output of the successful request if there is one, or an Err containing the original provider and the context value.

pub fn or_else(self, f: impl FnOnce(P, Cx) -> Out) -> Out

Returns the output of the successful request if there is one, or the return value of the given function that accepts the original provider and the context value.

pub fn has<Tag: TagFor<L>>( self, arg: Tag::ArgValue, transform: impl FnOnce(Tag::Value, Cx) -> Out, ) -> Self

Handle the case where the type marked by Tag is supplied by the provider.

pub fn has_value<T: 'static>(self, transform: impl FnOnce(T, Cx) -> Out) -> Self

Handle the case where a value of type T, marked by Value<T>, is supplied by the provider.

impl<'x, L: Lt, P: Provide<LtList<'x, L>>, Cx, Out> WhenProvider<LtList<'x, L>, P, HasContext<Cx>, Out>

pub fn has_ref<T: 'static + ?Sized>( self, transform: impl FnOnce(&'x T, Cx) -> Out, ) -> Self

Handle the case where a shared reference to a value of type T, marked by Ref<Value<T>>, is supplied by the provider.

pub fn has_mut<T: 'static + ?Sized>( self, transform: impl FnOnce(&'x mut T, Cx) -> Out, ) -> Self

Handle the case where a unique reference to a value of type T, marked by Mut<Value<T>>, is supplied by the provider.