def __init__(self, size: int) -> None:
'''
Initialize this fixed list to the passed length and all items of this
fixed list to ``None``.
Parameters
----------
size : IntType
Length to constrain this fixed list to.
Raises
----------
_BeartypeUtilCachedFixedListException
If this length is either not an integer *or* is but is
**non-positive** (i.e., is less than or equal to 0).
'''
# If this length is *NOT* an integer, raise an exception.
if not isinstance(size, int):
raise _BeartypeUtilCachedFixedListException(
'Fixed list length {!r} not integer.'.format(size))
# Else, this length is an integer.
# If this length is non-positive, raise an exception.
if size <= 0:
raise _BeartypeUtilCachedFixedListException(
'Fixed list length {!r} <= 0.'.format(size))
# Else, this length is positive.
# Make it so with the standard Python idiom for preallocating list
# space -- which, conveniently, is also the optimally efficient means
# of doing so. See also the timings in this StackOverflow answer:
# https://stackoverflow.com/a/10617221/2809027
super().__init__([None] * size)
def _die_if_slice_len_ne_value_len(self, index, value) -> None:
'''
Raise an exception only if the passed parameters when passed to the
parent :meth:`__setitem__` dunder method signify an external attempt to
change the length of this fixed length with slicing.
This function is intended to be called by the :meth:`__setitem__`
dunder method to validate the passed parameters.
Parameters
----------
index
0-based index, slice object, or tuple of 0-based indices and slice
objects to index this fixed list with.
value
Object to set this index(s) of this fixed list to.
Raises
----------
_BeartypeUtilCachedFixedListException
If this index is a **slice object** (i.e., :class:`slice` instance
underlying slice syntax) and this value is either:
* **Unsized** (i.e., unsupported by the :func:`len` builtin).
* Sized but has a length differing from that of this fixed list.
'''
# If this index is *NOT* a slice, silently reduce to a noop.
if not isinstance(index, slice):
return
# Else, this index is a slice.
# If this value is *NOT* a sized container, raise an exception.
if not isinstance(value, Sized):
raise _BeartypeUtilCachedFixedListException(
'{} slice {!r} not settable to unsized {}.'.format(
self._label, index, get_object_representation(value)))
# Else, this value is a sized container.
# 0-based first and one-past-the-last indices sliced by this slice.
start, stop_plus_one, _ = index.indices(len(self))
# Number of items of this fixed list sliced by this slice. By
# definition, this is guaranteed to be a non-negative integer.
slice_len = stop_plus_one - start
# Number of items of this sized container to set this slice to.
value_len = len(value)
# If these two lengths differ, raise an exception.
if slice_len != value_len:
raise _BeartypeUtilCachedFixedListException(
'{} slice {!r} of length {} not settable to '
'{} of differing length {}.'.format(
self._label,
index,
slice_len,
get_object_representation(value),
value_len,
))
def remove(self, *args):
raise _BeartypeUtilCachedFixedListException('{} not removable.'.format(
self._label))
def pop(self, *args):
raise _BeartypeUtilCachedFixedListException('{} not poppable.'.format(
self._label))
def extend(self, obj):
raise _BeartypeUtilCachedFixedListException(
'{} not extendable by {}.'.format(self._label,
get_object_representation(obj)))
def clear(self):
raise _BeartypeUtilCachedFixedListException('{} not clearable.'.format(
self._label))
def __imul__(self, value):
raise _BeartypeUtilCachedFixedListException(
'{} not multipliable by {}.'.format(
self._label, get_object_representation(value)))
def remove(self, *args) -> NoReturn:
raise _BeartypeUtilCachedFixedListException(
f'{self._label} not removable.')
def __delitem__(self, index):
raise _BeartypeUtilCachedFixedListException(
'{} index {!r} not deletable.'.format(self._label, index))
def pop(self, *args) -> NoReturn:
raise _BeartypeUtilCachedFixedListException(
f'{self._label} not poppable.')
def extend(self, obj) -> NoReturn:
raise _BeartypeUtilCachedFixedListException(
f'{self._label} not extendable by '
f'{get_object_representation(obj)}.')
def clear(self) -> NoReturn:
raise _BeartypeUtilCachedFixedListException(
f'{self._label} not clearable.')
def __imul__(self, value) -> NoReturn: # type: ignore[misc]
raise _BeartypeUtilCachedFixedListException(
f'{self._label} not multipliable by '
f'{get_object_representation(value)}.')
def __delitem__(self, index) -> NoReturn:
raise _BeartypeUtilCachedFixedListException(
f'{self._label} index {repr(index)} not deletable.')
