fml-check

Type checker for the FHIR Mapping Language: finds what a map gets wrong before it runs.

It follows every rule with the types of its variables and reports:

• elements that do not exist on the type they are read from or written to, including inherited ones, backbone elements and content references (Questionnaire.item.item);
• type annotations that are not a type of the element (src.deceased : string);
• unknown variables and writes into source variables;
• unknown or abstract types in create('Type'), and transforms with the wrong number of arguments;
• calls to groups that are not declared, or with the wrong number of arguments;
• element paths inside FHIRPath (where, check, (…)), as warnings, since a wrong path there gives an empty result instead of an error.

Groups without parameter types are checked with the types they are called with, which is how the cross-version maps are written. Those maps (R2–R5) check clean; on other public maps it found a typo in the FHIR test cases, a parameter a group uses without declaring it, and a condition that is never true because it reads system and code from a CodeableConcept instead of its codings.

Definitions come through a small Definitions trait. With the fhirschema feature, CoreDefinitions provides FHIR R4, R4B, R5 and R6 (6.0.0-ballot5), including the version-specific URLs the cross-version maps use (http://hl7.org/fhir/4.0/StructureDefinition/…). PackageDefinitions puts the StructureDefinitions of FHIR packages (profiles, extensions, logical models) in front of them.

use fml_check::{CoreDefinitions, Release, check};

let parse = fml_syntax::parse(source);
for diagnostic in check(&parse.tree(), &CoreDefinitions::new(Release::R5)) {
    eprintln!("{:?}: {}", diagnostic.severity, diagnostic.message);
}

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