Expand description
This is a companion crate for iref providing a derive macro to declare
enum types that converts into/from IRIs.
Storage and comparison of IRIs can be costly. One may prefer the use of an enum
type representing known IRIs with cheap conversion functions between the two.
This crate provides a way to declare such enums in an simple way through the
use of a IriEnum derive macro.
This macro will implement TryFrom<&Iri> and AsRef<Iri> for you.
Basic usage
Use #[derive(IriEnum)] attribute to generate the implementation of
TryFrom<&Iri> and AsRef<Iri> for the enum type.
The IRI of each variant is defined with the iri attribute:
use iref_enum::IriEnum;
#[derive(IriEnum, PartialEq, Debug)]
pub enum Vocab {
#[iri("https://schema.org/name")] Name,
#[iri("https://schema.org/knows")] Knows
}
let term: Vocab = static_iref::iri!("https://schema.org/name").try_into().unwrap();
assert_eq!(term, Vocab::Name)Each variant must have at most one parameter.
If it has a parameter, its type must implement TryFrom<&Iri> and
AsRef<Iri>.
Compact IRIs
The derive macro also support compact IRIs using the special iri_prefix attribute.
First declare a prefix associated to a given IRI.
Then any iri attribute of the form prefix:suffix we be expanded into the concatenation of the prefix IRI and suffix.
#[derive(IriEnum)]
#[iri_prefix("schema" = "https://schema.org/")]
pub enum Vocab {
#[iri("schema:name")] Name,
#[iri("schema:knows")] Knows
}