Struct pyo3::pycell::PyRef

pub struct PyRef<'p, T: PyClass> { /* private fields */ }

A wrapper type for an immutably borrowed value from a PyCell<T>.

See the PyCell documentation for more information.

Examples

You can use PyRef as an alternative to a &self receiver when

• you need to access the pointer of the PyCell, or
• you want to get a super class.

#[pyclass(subclass)]
struct Parent {
    basename: &'static str,
}

#[pyclass(extends=Parent)]
struct Child {
    name: &'static str,
 }

#[pymethods]
impl Child {
    #[new]
    fn new() -> (Self, Parent) {
        (Child { name: "Caterpillar" }, Parent { basename: "Butterfly" })
    }

    fn format(slf: PyRef<'_, Self>) -> String {
        // We can get *mut ffi::PyObject from PyRef
        use pyo3::AsPyPointer;
        let refcnt = unsafe { pyo3::ffi::Py_REFCNT(slf.as_ptr()) };
        // We can get &Self::BaseType by as_ref
        let basename = slf.as_ref().basename;
        format!("{}(base: {}, cnt: {})", slf.name, basename, refcnt)
    }
}

See the module-level documentation for more information.

Implementations

impl<'p, T: PyClass> PyRef<'p, T>

pub fn py(&self) -> Python<'_>

Returns a Python token that is bound to the lifetime of the PyRef.

impl<'p, T, U> PyRef<'p, T> where
    T: PyClass<BaseType = U>,
    U: PyClass, 

pub fn into_super(self) -> PyRef<'p, U>

Gets a PyRef<T::BaseType>.

While as_ref() returns a reference of type &T::BaseType, this cannot be used to get the base of T::BaseType.

But with the help of this method, you can get hold of instances of the super-superclass when needed.

Examples

#[pyclass(subclass)]
struct Base1 {
    name1: &'static str,
}

#[pyclass(extends=Base1, subclass)]
struct Base2 {
    name2: &'static str,
}

#[pyclass(extends=Base2)]
struct Sub {
    name3: &'static str,
}

#[pymethods]
impl Sub {
    #[new]
    fn new() -> PyClassInitializer<Self> {
        PyClassInitializer::from(Base1 { name1: "base1" })
            .add_subclass(Base2 { name2: "base2" })
            .add_subclass(Self { name3: "sub" })
    }
    fn name(slf: PyRef<'_, Self>) -> String {
        let subname = slf.name3;
        let super_ = slf.into_super();
        format!("{} {} {}", super_.as_ref().name1, super_.name2, subname)
    }
}

Trait Implementations

impl<'a, T: PyClass> AsPyPointer for PyRef<'a, T>

fn as_ptr(&self) -> *mut PyObject

Returns the underlying FFI pointer as a borrowed pointer.

impl<'p, T, U> AsRef<U> for PyRef<'p, T> where
    T: PyClass<BaseType = U>,
    U: PyClass, 

fn as_ref(&self) -> &T::BaseType

Converts this type into a shared reference of the (usually inferred) input type.

impl<T: PyClass + Debug> Debug for PyRef<'_, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'p, T: PyClass> Deref for PyRef<'p, T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<'p, T: PyClass> Drop for PyRef<'p, T>

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, T> From<PyRef<'a, T>> for Py<T> where
    T: PyClass, 

fn from(pyref: PyRef<'a, T>) -> Self

Converts to this type from the input type.

impl<'a, T> FromPyObject<'a> for PyRef<'a, T> where
    T: PyClass, 

fn extract(obj: &'a PyAny) -> PyResult<Self>

Extracts Self from the source PyObject.

impl<T: PyClass> IntoPy<Py<PyAny>> for PyRef<'_, T>

fn into_py(self, py: Python<'_>) -> PyObject

Performs the conversion.

impl<'a, T: PyClass> TryFrom<&'a PyCell<T>> for PyRef<'a, T>

type Error = PyBorrowError

The type returned in the event of a conversion error.

fn try_from(cell: &'a PyCell<T>) -> Result<Self, Self::Error>

Performs the conversion.