r3_patient — Build a FHIR R3 Patient, serialize it, validate it, and read it back

Run with:

cargo run --example r3_patient --features r3

The R3 model is laid out exactly like the R5 one, so everything here is the R5 example with r5 changed to r3. What differs is the content. Two differences show up in this one short program:

• A resource's id is a types::Id in R3, where R4 and R5 type it as a types::String.
• R3 has no canonical or url primitive at all; both arrived in R4.

The models keep such differences visible instead of papering over them.

The program#

use fhir::r3::coded::Coded;
use fhir::r3::codes::{AdministrativeGender, ContactPointSystem};
use fhir::r3::resources::Patient;
use fhir::r3::types::{Boolean, ContactPoint, HumanName, Id, String as FhirString};
use fhir::r3::validate::Validate;

fn main() {
    let patient = Patient::builder()
        .id(Id("pat-1".to_string())) // R3 types a resource id as `id`, not `string`
        .active(Boolean(true))
        .gender(Coded::Known(AdministrativeGender::Female))
        .name(vec![HumanName {
            family: Some(FhirString("Chalmers".to_string())),
            given: vec![FhirString("Jane".to_string())],
            ..Default::default()
        }])
        .telecom(vec![ContactPoint {
            system: Some(Coded::Known(ContactPointSystem::Phone)),
            value: Some(FhirString("+1 555 0100".to_string())),
            ..Default::default()
        }])
        .build()
        .expect("Patient has no required fields, so this cannot fail");

    let json = serde_json::to_string_pretty(&patient).expect("serialize");
    println!("{json}\n");

    // The model validates against the R3 constraints, not R5's.
    let issues = patient.validate();
    println!("validation issues: {}", issues.len());
    assert!(issues.is_empty());

    // Round-trip: canonical FHIR JSON parses back to an equal value.
    let parsed: Patient = serde_json::from_str(&json).expect("deserialize");
    assert_eq!(parsed, patient);
    println!("round-trip: ok");
}

Source: fhir/examples/r3_patient.rs in the repository.