Example of how to generate JSON Schemas programmatically

[tacman]

The documentation is a bit sparse on generating JSON Schemas programmatically,

To generate JSON Schemas programmatically, use the api_platform.json_schema.schema_factory service.

In particular, I want to build a schema from data, not from an existing class. That is, I'm trying to generate a schema to give some structure to my json blobs.

So I'm looking for an example that is something like

function generateSchemaController(
        SchemaFactoryInterface $schemaFactory
        ): Response
{
   // this is fictional, I'm not at all sure what it's supposed to be.
    $property = new Property('age', type: 'integer', 'minimum' => 18);
    $schemaFactory->addProperty($property);

   $json = $schemaFactor->generate();
   return new JsonResponse($json);
}

I see that there are classes for Property and Definition, but I'm not sure how to use them to generate a schema.

I've looked at a few other tools, but ApiPlatform is much more complete, I think an example that doesn't require a PHP class would help a lot. Thanks.