rustpython_vm/function/
either.rs

1use crate::{
2    convert::ToPyObject, AsObject, PyObject, PyObjectRef, PyResult, TryFromObject, VirtualMachine,
3};
4use std::borrow::Borrow;
5
6pub enum Either<A, B> {
7    A(A),
8    B(B),
9}
10
11impl<A: Borrow<PyObject>, B: Borrow<PyObject>> Borrow<PyObject> for Either<A, B> {
12    #[inline(always)]
13    fn borrow(&self) -> &PyObject {
14        match self {
15            Self::A(a) => a.borrow(),
16            Self::B(b) => b.borrow(),
17        }
18    }
19}
20
21impl<A: AsRef<PyObject>, B: AsRef<PyObject>> AsRef<PyObject> for Either<A, B> {
22    #[inline(always)]
23    fn as_ref(&self) -> &PyObject {
24        match self {
25            Self::A(a) => a.as_ref(),
26            Self::B(b) => b.as_ref(),
27        }
28    }
29}
30
31impl<A: Into<PyObjectRef>, B: Into<PyObjectRef>> From<Either<A, B>> for PyObjectRef {
32    #[inline(always)]
33    fn from(value: Either<A, B>) -> Self {
34        match value {
35            Either::A(a) => a.into(),
36            Either::B(b) => b.into(),
37        }
38    }
39}
40
41impl<A: ToPyObject, B: ToPyObject> ToPyObject for Either<A, B> {
42    #[inline(always)]
43    fn to_pyobject(self, vm: &VirtualMachine) -> PyObjectRef {
44        match self {
45            Self::A(a) => a.to_pyobject(vm),
46            Self::B(b) => b.to_pyobject(vm),
47        }
48    }
49}
50
51/// This allows a builtin method to accept arguments that may be one of two
52/// types, raising a `TypeError` if it is neither.
53///
54/// # Example
55///
56/// ```
57/// use rustpython_vm::VirtualMachine;
58/// use rustpython_vm::builtins::{PyStrRef, PyIntRef};
59/// use rustpython_vm::function::Either;
60///
61/// fn do_something(arg: Either<PyIntRef, PyStrRef>, vm: &VirtualMachine) {
62///     match arg {
63///         Either::A(int)=> {
64///             // do something with int
65///         }
66///         Either::B(string) => {
67///             // do something with string
68///         }
69///     }
70/// }
71/// ```
72impl<A, B> TryFromObject for Either<A, B>
73where
74    A: TryFromObject,
75    B: TryFromObject,
76{
77    fn try_from_object(vm: &VirtualMachine, obj: PyObjectRef) -> PyResult<Self> {
78        A::try_from_object(vm, obj.clone())
79            .map(Either::A)
80            .or_else(|_| B::try_from_object(vm, obj.clone()).map(Either::B))
81            .map_err(|_| vm.new_type_error(format!("unexpected type {}", obj.class())))
82    }
83}
rustpython_vm/function/either.rs

rustpython_vm/function/
either.rs
