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", so this trait is not object safe.

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> 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>

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>

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