Module query

Human-readable location queries for HL7 messages.

i.e. parsing “PID.5.1” to get the value of the first component of the fifth field

Querying HL7 messages

This module provides utilities for querying HL7 messages. This is useful for extracting specific values from an HL7 message, such as the patient’s name or the ordering provider’s name without having to manually traverse the message.

Location queries

A location query is a string that describes the location of a value within an HL7 message. The query is made up of the segment name, field index, repeat index, component index, and subcomponent index. Each part of the query is separated by a period (.), and each index is enclosed in square brackets ([]). For example, the query PID.5[1].1 would refer to the first subcomponent of the first component of the first repeat of the fifth field of the PID segment.

Examples

use hl7_parser::query::LocationQuery;
let query = LocationQuery::parse("MSH[1].2[3].4.5").unwrap();
assert_eq!(query.segment, "MSH");
assert_eq!(query.segment_index, Some(1));
assert_eq!(query.field, Some(2));
assert_eq!(query.repeat, Some(3));
assert_eq!(query.component, Some(4));
assert_eq!(query.subcomponent, Some(5));

use hl7_parser::query::LocationQuery;
let query = LocationQuery::parse("MSH.2.4").unwrap();
assert_eq!(query.segment, "MSH");
assert_eq!(query.segment_index, None);
assert_eq!(query.field, Some(2));
assert_eq!(query.repeat, None);
assert_eq!(query.component, Some(4));
assert_eq!(query.subcomponent, None);

Building location queries

A location query can also be built using a builder pattern. This is useful when you want to ensure that the query is valid at before using it.

use hl7_parser::query::LocationQueryBuilder;
let query = LocationQueryBuilder::new()
   .segment("MSH")
   .segment_index(1)
   .field(2)
   .repeat(3)
   .component(4)
   .subcomponent(5)
   .build()
   .unwrap();
assert_eq!(query.to_string(), "MSH[1].2[3].4.5");

Structs

LocationQuery

A location query that describes the location of a value within an HL7 message. The query is made up of the segment name, field index, repeat index, component index, and subcomponent index. Each part of the query is separated by a period (.), and each index is enclosed in square brackets ([]). For example, the query PID.5[1].1 would refer to the first subcomponent of the first component of the first repeat of the fifth field of the PID segment.

LocationQueryBuilder

A builder for creating a location query with error checking.

LocationQueryResultDisplay

Display the result of a location query, using the separators to decode escape sequences

Enums

LocationQueryBuildError

Errors that can occur when building a location query

LocationQueryResult

A result of a location query. This can be a segment, field, repeat, component, or subcomponent. The result contains a reference to the corresponding part of the message. The result can be used to get the raw value of the part of the message, or to display the value using the separators to decode escape sequences.

QueryParseError

An error that can occur when parsing a query

Functions

parse_location_query

Parse a location query from a string