fml

A command-line tool for the FHIR Mapping Language: check, format, compile, print and run FML maps. A single binary, no JVM.

cargo install fml-cli

Or download a binary for Linux, macOS or Windows from the releases page.

fml check maps/                    # syntax and type errors, rustc-style
fml check --format json maps/      # the same for editors and CI
fml fmt maps/                      # format in place
fml fmt --check maps/              # list unformatted files, exit 1 (CI)
fml compile map.fml -o map.json    # FML → StructureMap JSON (--fhir r4 for the R4 form)
fml print map.json                 # StructureMap JSON (R4 or R5) → FML
fml run map.fml input.json         # run a map over a FHIR resource
fml run Patient4to5.fml patient.json --maps R4toR5/ --maps codes/
                                   # with imported groups and ConceptMaps for translate()
fml run map.fml in.json --debug    # the $transform debug trace, as Parameters
fml run map.fml in.json --bundle   # the target and the resources the map produced
fml check --package hl7.fhir.us.core@6.1.0 maps/
                                   # with the profiles and extensions of a FHIR package

What each command is built on:

• check: the fml-check type checker against FHIR R4, R4B, R5 and R6; --fhir picks the release unversioned core URLs refer to, --package adds a FHIR package (a folder, or name@version from the package registry).
• fmt: the fml-syntax formatter, which keeps comments and refuses to write text that would change the map.
• compile and print: fml-model, which builds the same StructureMap as the HL7 reference compiler.
• run: the fml-engine StructureMap engine with FHIRPath; --maps and --package bring imported StructureMaps and ConceptMaps, --debug writes the trace, --bundle a collection Bundle with the resources the map produced.

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