Summary

Hello, I want to take my comment from older closed issue.
I miss the ability to generate guaranteed unique values. I used to use the FactoryBoy library for factories and there is a Sequence field for this purpose, which allows you to specify a function that will receive the next integer value at each call.
I would like to have a similar field in this library and would like to discuss a possible implementations.

I would like to hear feedback on the proposed solutions and can take on the implementation.

Basic Example

What are the possibilities I see:

@dataclass
class Person:
    email: str

1. Similar to __random__:

class PersonFactory(DataclassFactory[Person]):
    @classmethod
    def email(cls) -> str:
        return cls.__sequence__(lambda n: f'user{n}@domain.tld')

2. Similar to __random__ and Use:

class PersonFactory(DataclassFactory[Person]):
    email = Use(DataclassFactory.__sequence__, lambda n: f'user{n}@domain.tld')

3. Similar to FactoryBoy

class PersonFactory(DataclassFactory[Person]):
    email = Sequence(lambda n: f'user{n}@domain.tld')

Drawbacks and Impact

It will be possible to generate guaranteed unique or sequential values.

Unresolved questions

I would like to hear feedback on the proposed solutions and can take on the implementation.
Perhaps the maintainers can suggest why this might be a bad idea or suggest the best way this can be built into the current codebase.
It might be worth discussing how the sequence should be reset.