| # Licensed under a 3-clause BSD style license - see LICENSE.rst | |
| """ | |
| A module containing specialized collection classes. | |
| """ | |
| class HomogeneousList(list): | |
| """ | |
| A subclass of list that contains only elements of a given type or | |
| types. If an item that is not of the specified type is added to | |
| the list, a `TypeError` is raised. | |
| """ | |
| def __init__(self, types, values=[]): | |
| """ | |
| Parameters | |
| ---------- | |
| types : sequence of types | |
| The types to accept. | |
| values : sequence, optional | |
| An initial set of values. | |
| """ | |
| self._types = types | |
| super().__init__() | |
| self.extend(values) | |
| def _assert(self, x): | |
| if not isinstance(x, self._types): | |
| raise TypeError( | |
| "homogeneous list must contain only objects of " | |
| "type '{}'".format(self._types)) | |
| def __iadd__(self, other): | |
| self.extend(other) | |
| return self | |
| def __setitem__(self, idx, value): | |
| if isinstance(idx, slice): | |
| value = list(value) | |
| for item in value: | |
| self._assert(item) | |
| else: | |
| self._assert(value) | |
| return super().__setitem__(idx, value) | |
| def append(self, x): | |
| self._assert(x) | |
| return super().append(x) | |
| def insert(self, i, x): | |
| self._assert(x) | |
| return super().insert(i, x) | |
| def extend(self, x): | |
| for item in x: | |
| self._assert(item) | |
| super().append(item) | |