Trait NamedValuesAlg 

pub trait NamedValuesAlg { }

States that an argument is read from a collection of names and values.

A query string, a header collection, and a cookie collection carry names and values. Every interpretation presents one as a product, so an argument read from one has to be a product too: a value stating no names of its own is read by nobody, and would fail on the first request that reached it.

Nothing in a type says whether it is a product, so the type says it here. That turns the mistake into one the compiler catches rather than one a caller finds:

use alux_http::HttpProgramBuilder;

let builder = HttpProgramBuilder;
// A query string carries names and values, and `String` states none.
let _ = builder.op(()).query::<String>();

use alux_http::{HttpProgramBuilder, NamedValuesAlg};

/// What a caller narrows a search by, stated as the query string carries it.
struct Filters {
    since: u64,
}

impl NamedValuesAlg for Filters {}

let builder = HttpProgramBuilder;
let _ = builder.op(()).query::<Filters>();

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<Name, Value, State> NamedValuesAlg for HashMap<Name, Value, State>

An association from names to values is what a collection of them is, whatever it maps to.

impl<Name, Value> NamedValuesAlg for BTreeMap<Name, Value>

An association from names to values is what a collection of them is, whatever it maps to.

Implementors