Subclasses in the IR? about quicktype HOT 1 OPEN

There are a couple of pieces needed for inheritance:

• An IR representation of subclassing. This can be as simple as adding a "superclass" property to ClassType.

• A way to generate those subclasses from JSON Schema. The proper place for this is most likely JSONSchemaInput.ts.

• Target language support for subclasses. For most languages this is probably easy to implement. We probably won't support it on all languages (right away at least), so they should only be generated from JSON Schema if the target language supports them.

Once this is done, quicktype should be able to generate types and serializers for subclasses. Deserializers, however, would still be missing. To get those we'd need

• A mechanic in quicktype to figure out how to distinguish between subclasses of a common superclass. In the most general case this is quite difficult, but we could at first insist that each instance has a string field which has a different value for each subclass, which is quite common in JSON. The output of that would be a transformer that switches on that string and instantiates the correct subclass. This is the rockiest part of the whole chain, since transformers are still relatively new and a bit crufty.

• Transformers in the target languages that we want to support subclasses in. Right now transformers are only implemented in C# and Python. Luckily in JS/TypeScript/Flow they're relatively easy to implement.

I'm happy to help with all of this.

from quicktype.