Introduction

This is NCQA's and Firely's official support SDK for working with CQL on the Microsoft .NET (dotnet) platform. It contains an engine for executing ELM, and/or turning the contents of an ELM file into a .NET assembly so it can be called statically.

Release notes

This is release version 2.0 (alpha) of the engine. We expect parts of the public interface can to change. The engine has been tested by running it against the current NCQA HEDIS measures and CMS measures. There is quite some variation in how CQL is written and interpreted, so it is likely at this early stage that there will be deviations from other engines currently available.

The releases notes at firely-cql-sdk/releases for each major version will document these changes and (major) issues we have encountered.

Recent Changes

Translator Options Alignment (Issue #899)

The .NET CQL translator options have been aligned with the Java stack naming conventions and default values to ensure cross-platform consistency:

Property Renames:

• EnableListPromotion → DisableListPromotion (with inverted semantics)
• EnableListDemotion → DisableListDemotion (with inverted semantics)
• EnableIntervalPromotion and EnableIntervalDemotion remain unchanged

Updated Default Values:

• DisableListPromotion = true (List promotion disabled by default)
• DisableListDemotion = true (List demotion disabled by default)
• EnableIntervalPromotion = true (Interval promotion enabled by default)
• EnableIntervalDemotion = true (Interval demotion enabled by default)

These changes ensure the .NET SDK behaves consistently with the Java implementation and simplifies cross-platform test configuration sharing.

Getting Started

• Read how to get started with the Demo solution included in the repository.
• There is a great presentation on the engine from DevDays 2023.
• The CQL section in the .NET SDK documentation
• A word document with background documentation on the design. May be somewhat outdated.
• A diagram showing how all the classes and their dependencies involved.
• A graphic showing the main (internal) parts of the engine. May be somewhat outdated.

The presentation is a good place to start, but note that we have made some minor changes to the public surface, so the names of the classes in the presentation will differ from the examples in the Demo project itself.

Dev Start

During development, new alpha releases will appear on Firely's Github Package feed, to be able to use pre-release packages within the cql solution. To use theses packages you must add https://nuget.pkg.github.com/FirelyTeam/index.json to your NuGet sources:

• Get a Personal Access token (PAT) from github.com with scope read:packages

• Next open a console on your machine and run dotnet nuget add source --name github --username <USERNAME> --password <PAT> https://nuget.pkg.github.com/FirelyTeam/index.json

USERNAME: your username on GitHub PAT: your Personal access token with at least the scope read:packages

Further information can be found in docs/getting-started.md.

Support

We actively monitor the issues coming in through the GitHub repository at https://github.com/FirelyTeam/firely-cql-sdk/issues. You are welcome to register your bugs and feature suggestions there. For questions and broader discussions, we use the .NET FHIR Implementers chat and CQL chat on Zulip.

Contributing

We are welcoming contributions!

If you want to participate in this project, we're using Git Flow for our branch management. Please submit PRs with changes against the develop branch.