Trait PyFunctionArgument 

pub trait PyFunctionArgument<'a, 'holder, 'py, const IMPLEMENTS_FROMPYOBJECT: bool>: Sized + Sealed<IMPLEMENTS_FROMPYOBJECT> {
    type Holder: FunctionArgumentHolder;
    type Error: Into<PyErr>;

    const INPUT_TYPE: PyStaticExpr;

    // Required method
    fn extract(
        obj: Borrowed<'a, 'py, PyAny>,
        holder: &'holder mut Self::Holder,
    ) -> Result<Self, Self::Error>;
}

A trait which is used to help PyO3 macros extract function arguments.

#[pyclass] structs need to extract as PyRef<T> and PyRefMut<T> wrappers rather than extracting &T and &mut T directly. The Holder type is used to hold these temporary wrappers - the way the macro is constructed, these wrappers will be dropped as soon as the pyfunction call ends.

There exists a trivial blanket implementation for T: FromPyObject with Holder = ().

The const generic arg IMPLEMENTS_FROMPYOBJECT allows for const generic specialization of some additional types which don’t implement FromPyObject, such as &T for #[pyclass] types. All types should only implement this trait once; either by the FromPyObject blanket or one of the specialized implementations which needs a Holder.

Required Associated Constants

const INPUT_TYPE: PyStaticExpr

Available on crate feature experimental-inspect only.

Provides the type hint information for which Python types are allowed.

Required Associated Types

type Holder: FunctionArgumentHolder

type Error: Into<PyErr>

Required Methods

fn extract( obj: Borrowed<'a, 'py, PyAny>, holder: &'holder mut Self::Holder, ) -> Result<Self, Self::Error>

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<'a, 'holder, 'py, T> PyFunctionArgument<'a, 'holder, 'py, false> for Option<T>

where T: PyFunctionArgument<'a, 'holder, 'py, false>,

Allow Option<T> to be a function argument also for types which don’t implement FromPyObject

const INPUT_TYPE: PyStaticExpr

Available on crate feature experimental-inspect only.

type Holder = <T as PyFunctionArgument<'a, 'holder, 'py, false>>::Holder

type Error = <T as PyFunctionArgument<'a, 'holder, 'py, false>>::Error

fn extract( obj: Borrowed<'a, 'py, PyAny>, holder: &'holder mut T::Holder, ) -> Result<Self, Self::Error>

impl<'a, 'holder, T: PyClass<Frozen = False>> PyFunctionArgument<'a, 'holder, '_, false> for &'holder mut T

const INPUT_TYPE: PyStaticExpr = T::TYPE_HINT

Available on crate feature experimental-inspect only.

type Holder = Option<PyClassGuardMut<'a, T>>

type Error = PyErr

fn extract( obj: Borrowed<'a, '_, PyAny>, holder: &'holder mut Self::Holder, ) -> PyResult<Self>

impl<'a, 'holder, T: PyClass> PyFunctionArgument<'a, 'holder, '_, false> for &'holder T

const INPUT_TYPE: PyStaticExpr = T::TYPE_HINT

Available on crate feature experimental-inspect only.

type Holder = Option<PyClassGuard<'a, T>>

type Error = PyErr

fn extract( obj: Borrowed<'a, '_, PyAny>, holder: &'holder mut Self::Holder, ) -> PyResult<Self>

Implementors

impl<'a, 'holder, 'py, T> PyFunctionArgument<'a, 'holder, 'py, false> for &'holder Bound<'py, T>

where T: PyTypeCheck + 'a + 'py,

const INPUT_TYPE: PyStaticExpr = T::TYPE_HINT

type Holder = Option<Borrowed<'a, 'py, T>>

type Error = CastError<'a, 'py>

impl<'a, 'py, T> PyFunctionArgument<'a, '_, 'py, true> for T

where T: FromPyObject<'a, 'py>,

const INPUT_TYPE: PyStaticExpr = T::INPUT_TYPE

type Holder = ()

type Error = <T as FromPyObject<'a, 'py>>::Error