Struct pyo3::pycell::PyRef[−][src]

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

Expand description

Wraps a borrowed reference to a value in a PyCell<T>.

See the PyCell documentation for more.

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)
    }
}

Implementations

[src]

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

[src]

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

Returns a Python token. This function is safe since PyRef has the same lifetime as a GILGuard.

[src]

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

[src]

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)
    }
}