Function when_provider

pub fn when_provider<L: Lt, P: Provide<L>, Out>(
    provider: P,
) -> WhenProvider<L, P, NoContext, Out>

Helper function for requesting one of multiple possible values. See also request! and Provide::request().

See WhenProvider information about the methods used to request values.

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())
}