{
  "resourceType": "CodeSystem",
  "status": "draft",
  "content": "not-present",
  "name": "NexusTemplateCS",
  "id": "nexus-template-codes",
  "title": "Nexus Template CodeSystem",
  "description": "The slugs that name a Nexus EMR template, for use where a template is referenced as a `Coding`.\n\nA letter composed from a stored template carries one `Composition.meta.tag` from this system, whose\ncode is the template's slug -- the value of the marker identifier on the template `List`, never that\nlist's resource id, so the reference survives a template being re-seeded or moved between stores. A\ntag rather than an extension because \"every letter built from this template\" is a search, and `_tag`\nis a base R4 search parameter.\n\n**The coding view of a registry whose identifier view is already declared.**\n`NamingSystem/nexus-template` names the identifier a `List` carries in order to BE a template. One\nvalue space, two URLs, and both are correct: a NamingSystem states the identifiers a system is known\nby and cannot serve as a `Coding.system`.\n\n**Content is not held in this specification.** Slugs are minted by whoever authors a template and\nthe set is per-tenant reference data held as `List` resources, discovered by search. This declares\nthe system's identity and leaves its membership where it lives, rather than pinning a snapshot that\nwould be stale on publication.\n\n**Do not match on the final URL segment.** A second, retired address ends in the same word:\n`http://services.well.com/fhir/categories/letter-template` was a `DocumentReference.category` system\ncarrying one fixed code, marking a resource as BEING a template, from when a template was a\n`DocumentReference`. It is a different artifact answering a different question, and it has its own\nhome on this guide's base -- `nexus-letter-template` in `nexus-composition-type`.\n\n**MIGRATION.** Nexus EMR writes this system today at\n`http://services.well.com/fhir/tags/document-reference/letter-template` (FHIR-370): it is live in\nstored `Composition.meta.tag` codings and in code, and is under migration to the canonical declared\nhere. Write the canonical; when reading, match both addresses exactly rather than on their shared\nfinal segment. The `document-reference` in the pre-migration address is vestigial -- letters are\n`Composition`, and the tag rides `Composition`.",
  "url": "https://fhir.apps.health/CodeSystem/nexus-template",
  "experimental": false,
  "caseSensitive": true
}