mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-07-26 20:54:39 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

Improve extended slicing support in builtin types and classes. Specifically:

Browse source 
- Specialcase extended slices that amount to a shallow copy the same way as
   is done for simple slices, in the tuple, string and unicode case.

 - Specialcase step-1 extended slices to optimize the common case for all
   involved types.

 - For lists, allow extended slice assignment of differing lengths as long
   as the step is 1. (Previously, 'l[:2:1] = []' failed even though
   'l[:2] = []' and 'l[:2:None] = []' do not.)

 - Implement extended slicing for buffer, array, structseq, mmap and
   UserString.UserString.

 - Implement slice-object support (but not non-step-1 slice assignment) for
   UserString.MutableString.

 - Add tests for all new functionality.
This commit is contained in:
Thomas Wouters 2007-08-28 15:28:19 +00:00
parent 0f4a14b56f
commit 3ccec68a05
16 changed files with 730 additions and 120 deletions
Download patch file Download diff file Expand all files Collapse all files

42
Lib/UserString.py
View file

@ -149,15 +149,41 @@ class MutableString(UserString):
def __hash__(self):
raise TypeError, "unhashable type (it is mutable)"
def __setitem__(self, index, sub):
if index < 0:
index += len(self.data)
if index < 0 or index >= len(self.data): raise IndexError
self.data = self.data[:index] + sub + self.data[index+1:]
if isinstance(index, slice):
if isinstance(sub, UserString):
sub = sub.data
elif not isinstance(sub, basestring):
sub = str(sub)
start, stop, step = index.indices(len(self.data))
if step == -1:
start, stop = stop+1, start+1
sub = sub[::-1]
elif step != 1:
# XXX(twouters): I guess we should be reimplementing
# the extended slice assignment/deletion algorithm here...
raise TypeError, "invalid step in slicing assignment"
start = min(start, stop)
self.data = self.data[:start] + sub + self.data[stop:]
else:
if index < 0:
index += len(self.data)
if index < 0 or index >= len(self.data): raise IndexError
self.data = self.data[:index] + sub + self.data[index+1:]
def __delitem__(self, index):
if index < 0:
index += len(self.data)
if index < 0 or index >= len(self.data): raise IndexError
self.data = self.data[:index] + self.data[index+1:]
if isinstance(index, slice):
start, stop, step = index.indices(len(self.data))
if step == -1:
start, stop = stop+1, start+1
elif step != 1:
# XXX(twouters): see same block in __setitem__
raise TypeError, "invalid step in slicing deletion"
start = min(start, stop)
self.data = self.data[:start] + self.data[stop:]
else:
if index < 0:
index += len(self.data)
if index < 0 or index >= len(self.data): raise IndexError
self.data = self.data[:index] + self.data[index+1:]
def __setslice__(self, start, end, sub):
start = max(start, 0); end = max(end, 0)
if isinstance(sub, UserString):