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/test/string_tests.py b/Lib/test/string_tests.py
index d38e4a9..d0f8c03 100644
--- a/Lib/test/string_tests.py
+++ b/Lib/test/string_tests.py
@@ -912,7 +912,6 @@
self.checkequal(u'abc', 'abc', '__getitem__', slice(0, 1000))
self.checkequal(u'a', 'abc', '__getitem__', slice(0, 1))
self.checkequal(u'', 'abc', '__getitem__', slice(0, 0))
- # FIXME What about negative indices? This is handled differently by [] and __getitem__(slice)
self.checkraises(TypeError, 'abc', '__getitem__', 'def')
@@ -926,10 +925,21 @@
self.checkequal('', 'abc', '__getslice__', 1000, 1000)
self.checkequal('', 'abc', '__getslice__', 2000, 1000)
self.checkequal('', 'abc', '__getslice__', 2, 1)
- # FIXME What about negative indizes? This is handled differently by [] and __getslice__
self.checkraises(TypeError, 'abc', '__getslice__', 'def')
+ def test_extended_getslice(self):
+ # Test extended slicing by comparing with list slicing.
+ s = string.ascii_letters + string.digits
+ indices = (0, None, 1, 3, 41, -1, -2, -37)
+ for start in indices:
+ for stop in indices:
+ # Skip step 0 (invalid)
+ for step in indices[1:]:
+ L = list(s)[start:stop:step]
+ self.checkequal(u"".join(L), s, '__getitem__',
+ slice(start, stop, step))
+
def test_mul(self):
self.checkequal('', 'abc', '__mul__', -1)
self.checkequal('', 'abc', '__mul__', 0)