Add TypeAdapter support for JSON

[hoesler]

Add support for pydantic TypeAdapter to allow schema objects to be generated from primitive types or lists for example (e.g. TypeAdapter(List[Transaction])).

[rlouf]

Thank you! Could you add some tests?

[hoesler]

I actually looked into adding a test, but found that the relevant test is skipped. So what would you suggest here?

[hoesler]

BTW, I guess this could also replace the recently added enum support from #1277, as you can just do something like:

class Color(Enum):
    RED = 1
    BLUE = 2

generator = outlines.generate.json(model, TypeAdapter(Color))

[rlouf]

Could you give me an example of how you would use this?

[hoesler]

My motivation was to generate a list of objects:

class Transaction(BaseModel):
   ...

generator = outlines.generate.json(model, TypeAdapter(List[Transaction]))

But one could use it for primitives as well. See for example the comment above for Enums.

[rlouf]

I wonder if there is a way to let users pass List[Object] and hide the use of TypeAdapter from them?

[hoesler]

Sure, I could do that. But I don’t know if I would recommend it. While convenient, the function might become a bit hard to extend in the future or simply complex to define. Maybe there will be types you want to handle differently, maybe another library other than Pydantic will be added… But in the end it’s your decision.

[rlouf]

You're probably right, we'll leave it as is for now. We just need to get to full coverage before merging!

[hoesler]

Happy to add tests, but please give me some guidance here.
Intuitively I would add a schema_object parameter to test_generate_json in test_generate.py. But this test is skipped, because it fails for some models? Shouldn't we just skip those models instead of all? And by executing the test with all the different concrete models, doesn't that make it an integration test? If I'm right, how do you decide if a test goes to this file or to any of the test_integration_*.py files?

And should I remove the specific handling of the Enum type in favor of the TypeAdapter?