pub trait Part: Sealed { }Expand description
Marker trait for types that mark a part of a URI.
This trait exists solely to categorize types that mark a part of the URI,
currently Path and Query. Said another way, types that implement
this trait are marker types that represent a part of a URI at the
type-level.
This trait is sealed: it cannot be implemented outside of Rocket.
Usage
You will find this trait in traits like UriDisplay or structs like
Formatter as the bound on a generic parameter: P: Part. Because the
trait is sealed, the generic type is guaranteed to be instantiated as one of
Query or Path, effectively creating two instances of the generic
items: UriDisplay<Query> and UriDisplay<Path>, and Formatter<Query>
and Formatter<Path>. Unlike having two distinct, non-generic traits, this
approach enables succinct, type-checked generic implementations of these
items.