Constructors for `PyLong` and `PyInt`

[a1phyr]

Most types in pyo3::types have helper methods to create them easily (examples: PyString::new, PyBool::new). Is there a reason why there is no such method for PyLong and PyInt or is it an overlook ? Could we imagine adding them ?

Being able to build python objects in an easy and type-safe manner is a real strength of pyo3, and having a hole here seems a bit weird.

[mejrs]

Thanks for the suggestion!

One thing that is tricky is deciding what this function should look like. Should it accept just a single integer type, or should it accept multiple types, via a trait?

Fwiw, I have used 0_u8.into_py(py) the one time I needed this. What is your use case for this?

[bjohnnyd]

@mejrs if this is not being worked on happy to take it on?

[mejrs]

@mejrs if this is not being worked on happy to take it on?

Please do!

[iyakushev]

@bjohnnyd are you still workin on it? @mejrs I've also noticed that PyFloat::new accepts only c_double aka f64. Perhaps, if PyLong needs a more generic approach, it might be implemented for PyFloat as well

[bjohnnyd]

@iyakushev I have some local changes for a future PR, so yes working on it. Though some discussion on whether it should be:

1. A generic implementation?
2. If generic, should it be via a trait?

would be beneficial.

I can make a PR and we can move the discussion there, unless @mejrs thinks otherwise?

[Trolldemorted]

as of now, is it possible to build rust functions that return Py<PyLong> without casting magic?

[nicoCalvo]

Is there a workaround for this? I'm having a hard time to build a PyInt/PyLong object from rust numeric types.

[birkenfeld]

@nicoCalvo as @mejrs said, you can go the into_py route and then downcast. For interest, what to you need the PyLong object for?

[nicoCalvo]

@birkenfeld Thanks. I solved with rust native usize and converting to float. I was working on a rust implementation of python's dictor lib: https://github.com/nicoCalvo/dicto_r/blob/v1.0/src/lib.rs#L265 Any comments/suggestions are very welcomed as these are my first steps with Pyo3 and have not so much experience with rust either.

[birkenfeld]

@nicoCalvo I have to admit I don't understand that code. What is the original type of inner_object?