fml-engine

A StructureMap engine for the FHIR Mapping Language: runs maps over FHIR JSON, the way the HL7 reference engine does.

Passes the reference tests. Every JSON structure-mapping test of the FHIR test cases (12 of 12, R4B and R5).
Converts FHIR versions. With the HL7 cross-version maps and their ConceptMaps, it converts 2,863 of the 2,881 R4 specification examples that have a map to R5: R4 medicationReference becomes the R5 CodeableReference, Encounter class becomes a list of CodeableConcepts, and so on. A code a ConceptMap does not know is left out, as the reference engine does, and reported in warnings.
The whole language. Groups and extends, source filters (type, where, check, log, list modes, default), targets that create or reuse elements (repeating, choice elements written as valueReference, share), dependent groups, default groups chosen by type, imported maps, primitives with their id and extensions, and rules with several sources.
Transforms: create, copy, evaluate, truncate, cast, append, translate, reference, pointer, uuid, cc, c, id, cp, qty, escape (html, xml, json), and the IG's date and time transforms: toDateTime, toDate, toTime with format patterns (dd/MM/yyyy HH:mm, MMMM d, yyyy, …) and unixToDateTime, unixToDate, unixToTime. Not yet: dateOp, which the IG lists without defining.
Produced resources. Resources a map creates outside the target (a create with no target element) come back in produced, ready for a Bundle.
Follows the IG where it says more than the reference engine. Named groups and nested rules after then both run; a source's min..max is enforced; evaluate with several values makes one target per value; a group name in several imported maps is an error; cast takes FHIR. and System. types and checks the value.
Debug trace. with_trace(true) records the trace of the IG's debug page for $transform?debug=true: enter / step / exit events with their depth, the position in the StructureMap (StructureMap.group[0].rule[2]) and the variables in scope. debug_parameters writes the Parameters response with traceStatus (complete, truncated, stopped), the text range of each event (rows and UTF-16 columns, from fml_model::Locations), and an outcome with the failure and where it happened, why events were left out, and values left out of the result.
Safe to run on maps you did not write. Limits bound the group depth, the rules run, the values created and the size of the trace; a flag cancels a run. Failures say what kind they are (ErrorKind) and where (position).
Pluggable. Structure definitions come from fml-check's Definitions, FHIRPath from an Expressions implementation (the fhirpath feature uses octofhir-fhirpath), imported maps from a MapResolver, ConceptMaps from a ConceptMapResolver, and any other ConceptMap through a TranslateService ($translate on a terminology server). ConceptMaps are found by URL and by the canonical URLs they replace. uuid() and new ids come from an IdGenerator (SequentialIds makes runs repeatable).

use fml_check::{CoreDefinitions, Release};
use fml_engine::{ConceptMapSet, Engine, FhirPathExpressions, Limits, MapSet};

let definitions = CoreDefinitions::new(Release::R5);
let expressions = FhirPathExpressions::new(Release::R5).await?;
let output = Engine::new(&definitions, expressions)
    .with_maps(&maps)                 // MapSet: StructureMaps for `imports`
    .with_concept_maps(&concept_maps) // ConceptMapSet: for translate()
    .with_limits(Limits::default())   // depth, rules, values, trace size
    .transform(&map, &input)
    .await?;
println!("{}", output.target);        // also: output.produced, output.warnings

Part of fml-rs. Licensed under MIT or Apache-2.0.

fml-engine 0.2.0

fml-engine