Improve extended slicing support in builtin types and classes. Specifically:
- 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.
diff --git a/Lib/UserString.py b/Lib/UserString.py
index 60dc34b..9c58a34 100755
--- a/Lib/UserString.py
+++ b/Lib/UserString.py
@@ -149,15 +149,41 @@
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):