Method next

crates/vm/src/stdlib/itertools.rs:75–119

(zelf: &Py<Self>, vm: &VirtualMachine)

    impl IterNext for PyItertoolsChain {
        fn next(zelf: &Py<Self>, vm: &VirtualMachine) -> PyResult<PyIterReturn> {
            let Some(source) = zelf.source.read().clone() else {
                return Ok(PyIterReturn::StopIteration(None));
            };
            let next = loop {
                let maybe_active = zelf.active.read().clone();
                if let Some(active) = maybe_active {
                    match active.next(vm) {
                        Ok(PyIterReturn::Return(ok)) => {
                            break Ok(PyIterReturn::Return(ok));
                        }
                        Ok(PyIterReturn::StopIteration(_)) => {
                            *zelf.active.write() = None;
                        }
                        Err(err) => {
                            break Err(err);
                        }
                    }
                } else {
                    match source.next(vm) {
                        Ok(PyIterReturn::Return(ok)) => match ok.get_iter(vm) {
                            Ok(iter) => {
                                *zelf.active.write() = Some(iter);
                            }
                            Err(err) => {
                                break Err(err);
                            }
                        },
                        Ok(PyIterReturn::StopIteration(_)) => {
                            break Ok(PyIterReturn::StopIteration(None));
                        }
                        Err(err) => {
                            break Err(err);
                        }
                    }
                }
            };
            match next {
                Err(_) | Ok(PyIterReturn::StopIteration(_)) => {
                    *zelf.source.write() = None;
                }
                _ => {}
            };
            next
        }
    }

    #[pyattr]