HL7 v2 derive

Derive macros for hl7-2: map a struct's fields to HL7 v2 message paths once, in the type definition, instead of writing the same accessor calls at every call site.

You do not depend on this crate directly. hl7-2 re-exports both macros behind its derive feature:

hl7-2 = { version = "0.2", features = ["derive"] }

Keeping the macros in a crate of their own is what lets the default build of hl7-2 keep exactly one dependency: syn and quote are compiled only for callers who ask for the macros.

Usage

use hl7_2::{FromHl7, ToHl7, Raw};

#[derive(FromHl7, ToHl7)]
struct Admission {
    #[hl7("PID-1")]      sequence: u32,
    #[hl7("PID-3")]      identifiers: Vec<String>,
    #[hl7("PID-5.1.1")]  family_name: String,
    #[hl7("PID-8")]      sex: Option<String>,
    #[hl7(nested)]       visit: Visit,   // its own FromHl7 / ToHl7
    #[hl7(raw)]          raw: Raw,       // the whole message, kept alongside
}

let admission: Admission = hl7_2::parse(text)?.decode()?;
assert_eq!(admission.family_name, "EVERYWOMAN");

// The one vendor field no struct models — same object, no second parse.
assert_eq!(admission.raw.get("ZPD-1")?.as_deref(), Some("local"));

One attribute per field:

Field types convert through hl7_2::FromHl7Value / ToHl7Value: String, bool, the integer and floating-point types, and Option<T> and Vec<T> of those — Option for a value that may be absent, Vec for one that repeats. A plain type is required, and a path that names nothing is Error::MissingField. Implement hl7_2::FromHl7Text for a domain type of your own and Option and Vec of it follow.

Writing needs the segments to exist already; build the message with hl7_2::Builder (whose encode method takes a ToHl7) or add them with Message::append_segment.

See also

• hl7-2 — the library these macros are for; its spec/index.md §6 is the normative description of struct mode
• er7 — the ER7 encoding layer

License

MIT OR Apache-2.0 OR BSD-3-Clause OR GPL-2.0-only OR GPL-3.0-only