EFv2: How do I add additional types to emit for model/union expressions?

[tadfisher]

I'm trying out the new emitter framework, and I'm running into an issue: my target language (Haskell) doesn't support anonymous record/union types, so I need to identify these and generate named type declarations and refer to them.

I found some code in http-client-js that clones these types and adds a name, but it doesn't appear to be used. I tried this approach, but the cloned types don't appear in the mutated namespace. My test code:

const program = await getProgram(`
  namespace DemoService;
  model Widget extends Record<unknown> {
    id: string;
    weight: int32;
    color: "blue" | "red";
  };
`);

// Mutates anonymous types to be named.
const anonymousMutatorRecord: unsafe_MutatorRecord<Model | Union> = {
  filter(t) {
    return MutatorFlow.MutateAndRecur;
  },
  mutate(t, clone) {
    if (!clone.name) {
      clone.name = $.type.getPlausibleName(clone);
    }
  },
};

const anonymousMutator: Mutator = {
  name: "Anonymous types",
  Model: anonymousMutatorRecord,
  Union: anonymousMutatorRecord,
};

const { realm, type } = mutateSubgraphWithNamespace(
  program,
  [anonymousMutator],
  program.getGlobalNamespaceType(),
);

const models = Array.from((type as Namespace).models.values());

// I expect the named union to show up here, but it is empty
const unions = Array.from((type as Namespace).unions.values());

Is there some additional work needed to access the cloned union type so I can emit it separately from the source model?

[tadfisher]

I managed to do this with Alloy contexts and no mutation. The context has a function to deanonymize a type:

export interface NamespaceContext {
  /** Create a clone of [type] with a generated name and return a reference to that type. */
  deanonymizeType(type: Model | Union): Refkey;
}

And the component implements it like:

export function NamespaceDeclaration(props: NamespaceDeclarationProps) {
  const additionalTypes: [Refkey, Type][] = reactive([]);

  const namespaceContext: NamespaceContext = {
    deanonymizeType(type) {
      const clone = $.type.clone({ ...type, name: generateName(type) });
      const refkey = getRefkey(type);
      additionalTypes.push([refkey, clone]);
      return refkey;
    },
  };

  return (
    <For each={additionalTypes}>
      {([refkey, type]) => <TypeDeclaration type={type} refkey={refkey} />}
    </For>
  );
}