#[new]

#[pyo3(signature = (initial=None))]

fn new(py: Python<'_>, initial: Option<&Bound<'_, PyList>>) -> PyResult<Self> {

let mut list = UniqueList {

items: Vec::new(),

seen: HashSet::new(),

};

if let Some(init) = initial {

for item in init.iter() {

list.append(py, item.unbind())?;

}

}

Ok(list)

}

fn append(&mut self, py: Python<'_>, item: PyObject) -> PyResult<()> {

let hash = item.bind(py).hash()? as u64;

if self.seen.insert(hash) {

self.items.push(item);

}

Ok(())

}

fn to_list(&self, py: Python<'_>) -> PyResult<PyObject> {

let list = PyList::new(py, self.items.iter().map(|x| x.bind(py)))?;

Ok(list.unbind().into())

}

fn __len__(&self) -> usize {

self.items.len()

}

fn __getitem__(&self, py: Python<'_>, idx: isize) -> PyResult<PyObject> {

let len = self.items.len() as isize;

let actual_idx = if idx < 0 { len + idx } else { idx };

if actual_idx < 0 || actual_idx >= len {

return Err(pyo3::exceptions::PyIndexError::new_err(

"list index out of range",

));

}

Ok(self.items[actual_idx as usize].clone_ref(py))

}

fn __contains__(&self, _py: Python<'_>, item: &Bound<'_, PyAny>) -> PyResult<bool> {

let hash = item.hash()? as u64;

Ok(self.seen.contains(&hash))

}

fn __iter__(&self, py: Python<'_>) -> PyResult<PyObject> {

let list = self.to_list(py)?;

list.bind(py).call_method0("__iter__").map(|x| x.unbind())

}

fn __repr__(&self, py: Python<'_>) -> PyResult<String> {

let list = self.to_list(py)?;

let repr = list.bind(py).repr()?;

Ok(format!("UniqueList({})", repr))

}

fn __bool__(&self) -> bool {

!self.items.is_empty()

}