Macro pyo3::create_exception

macro_rules! create_exception {
    ($module : ident, $name : ident, $base : ty) => { ... };
}

Defines a new exception type.

Syntax

create_exception!(module, MyError, BaseException)

• module is the name of the containing module.
• MyError is the name of the new exception type.
• BaseException is the superclass of MyError, usually pyo3::exceptions::PyException.

Examples

use pyo3::prelude::*;
use pyo3::create_exception;
use pyo3::types::IntoPyDict;
use pyo3::exceptions::PyException;

create_exception!(mymodule, CustomError, PyException);

fn main() {
    Python::with_gil(|py| {
        let error_type = py.get_type::<CustomError>();
        let ctx = [("CustomError", error_type)].into_py_dict(py);
        let type_description: String = py
            .eval("str(CustomError)", None, Some(&ctx))
            .unwrap()
            .extract()
            .unwrap();
        assert_eq!(type_description, "<class 'mymodule.CustomError'>");
        pyo3::py_run!(py, *ctx, "assert CustomError('oops').args == ('oops',)");
   });
}