json-ld 0.6.1

A JSON-LD implementation
Documentation 
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//! This simple example shows how to use an enum type (`Foaf`) to replace IRIs (`IriBuf`) as
//! identifiers in the expanded document.
//! This can reduce the cost of storing and comparing actual IRIs.
//! The only constraint is to define convertions between the type and `Iri`. It also must implement
//! `Clone`, `PartialEq`, `Eq` and `Hash`.
//! Since the `Foaf` type does not cover every possible IRIs, we use the `Lexicon` wrapper to
//! cover the rest. The identifer type (`Id`) is then `Lexicon<Foaf>`.
//! See the `custom-ids-iref-enum.rs` example to see how to simplify the definition of `Foaf` using
//! the `iref-enum` crate.
//#![feature(proc_macro_hygiene)]

extern crate async_std;
extern crate iref;
#[macro_use]
extern crate static_iref;
extern crate json_ld;

use iref::Iri;
use json_ld::{context, Document, Lexicon, NoLoader, Object};
use serde_json::Value;
use std::convert::TryFrom;

// Parts of the FOAF vocabulary will need.
#[derive(Clone, Copy, PartialEq, Eq, Hash)]
pub enum Foaf {
	Name,
	Mbox,
}

// Convertion from Iri
impl<'a> TryFrom<Iri<'a>> for Foaf {
	type Error = ();

	fn try_from(iri: Iri<'a>) -> Result<Foaf, ()> {
		match iri {
			_ if iri == iri!("http://xmlns.com/foaf/0.1/name") => Ok(Foaf::Name),
			_ if iri == iri!("http://xmlns.com/foaf/0.1/mbox") => Ok(Foaf::Mbox),
			_ => Err(()),
		}
	}
}

impl iref::AsIri for Foaf {
	fn as_iri(&self) -> Iri {
		match self {
			Foaf::Name => iri!("http://xmlns.com/foaf/0.1/name"),
			Foaf::Mbox => iri!("http://xmlns.com/foaf/0.1/mbox"),
		}
	}
}

type Id = Lexicon<Foaf>;

#[async_std::main]
async fn main() {
	// The JSON-LD document to expand.
	let doc: Value = serde_json::from_str(
		r#"
		{
			"@context": {
				"name": "http://xmlns.com/foaf/0.1/name",
				"email": "http://xmlns.com/foaf/0.1/mbox"
			},
			"@id": "timothee.haudebourg.net",
			"name": "Timothée Haudebourg",
			"email": "author@haudebourg.net"
		}
	"#,
	)
	.unwrap();

	// JSON document loader.
	let mut loader = NoLoader::<Value>::new();

	// Expansion.
	let expanded_doc = doc
		.expand::<context::Json<Value, Id>, _>(&mut loader)
		.await
		.unwrap();

	// Iterate through the expanded objects.
	for object in expanded_doc {
		if let Object::Node(node) = object.as_ref() {
			println!("node: {}", node.id().unwrap()); // print the `@id`
			for name in node.get(Foaf::Name) {
				// <- Note how we can directly use `Foaf` here.
				println!("name: {}", name.as_str().unwrap());
			}

			for name in node.get(Foaf::Mbox) {
				// <- Note how we can directly use `Foaf` here.
				println!("email: {}", name.as_str().unwrap());
			}
		}
	}
}