The Clinical Quality Language (CQL) is a high-level, domain-specific language focused on clinical quality measures and clinical decision support. It was developed to facilitate the authoring, sharing, and deployment of clinical logic and reasoning artifacts in the healthcare domain.
To be able to evaluate CQL against input data, you first need to convert CQL to ELM (Expression Logical Model)—an intermediate, lower-level format for representing the logical expressions contained in CQL. ELM can then be fed to the CQL engine for evaluation.
I've built this online too to provide a convenient way to convert CQL to ELM, whether you are testing/debugging your CQL or pre-compiling it to create a CQL library on a FHIR server. The conversion can be performed either server-side or client-side (both use the Java HAPI FHIR library). When using the client-side conversion, the CQL-to-ELM translation loads the Doppio JVM to execute the Java code in the browser. This is experimental and may not work in all browsers.