Support for FHIR package registry and namespaces

[JPercival]

In CQL, you can include a Library in a different namespace (which, loosely, implies a different project):

library Demo

include other.namespace.UltraLibrary as UL

define "Use UL":
    UL.X

The cql-language-server should know how to resolve those included libraries if they aren't in the current directory. This may require looking up the correct package on the FHIR package registry and downloading / caching it. It may also require support from the CQL compiler in order to do this correctly. In addition, the cql-language-server needs support for specifying how or where to resolve namespaces from. This is handled in the CQL compiler as the "NamespaceManager." Some namespaces may be able to be auto-detected, while others may require a configuration file in the local project.

[rob-reynolds]

What is the path to get from a Library in a different namespace to a CQL Library in a FHIR Library resource?

[rob-reynolds]

Like is is it:

• not in current directory
• if not exists .fhir/packages/other.namespace/UltraLibrary.json fetch FHIR package registry other.namespace
• .fhir/packages/other.namespace/UltraLibrary.json
• content where contentType= text/cql
• base64 decode into memory

[JPercival]

Almost. The namespace corresponds to the root IG url in most cases, which is associated with a package. There needs to be a facility for manually specifying that too, I think.