Generalize tuple() to work nicely with iterators.
NEEDS DOC CHANGES.
This one surprised me! While I expected tuple() to be a no-brainer, turns
out it's actually dripping with consequences:
1. It will *allow* the popular PySequence_Fast() to work with any iterable
object (code for that not yet checked in, but should be trivial).
2. It caused two std tests to fail. This because some places used
PyTuple_Sequence() (the C spelling of tuple()) as an indirect way to test
whether something *is* a sequence. But tuple() code only looked for the
existence of sq->item to determine that, and e.g. an instance passed
that test whether or not it supported the other operations tuple()
needed (e.g., __len__). So some things the tests *expected* to fail
with an AttributeError now fail with a TypeError instead. This looks
like an improvement to me; e.g., test_coercion used to produce 559
TypeErrors and 2 AttributeErrors, and now they're all TypeErrors. The
error details are more informative too, because the places calling this
were *looking* for TypeErrors in order to replace the generic tuple()
"not a sequence" msg with their own more specific text, and
AttributeErrors snuck by that.
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 5584587..bfe032f 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -275,6 +275,39 @@
except OSError:
pass
+ # Test tuples()'s use of iterators.
+ def test_builtin_tuple(self):
+ self.assertEqual(tuple(SequenceClass(5)), (0, 1, 2, 3, 4))
+ self.assertEqual(tuple(SequenceClass(0)), ())
+ self.assertEqual(tuple([]), ())
+ self.assertEqual(tuple(()), ())
+ self.assertEqual(tuple("abc"), ("a", "b", "c"))
+
+ d = {"one": 1, "two": 2, "three": 3}
+ self.assertEqual(tuple(d), tuple(d.keys()))
+
+ self.assertRaises(TypeError, tuple, list)
+ self.assertRaises(TypeError, tuple, 42)
+
+ f = open(TESTFN, "w")
+ try:
+ for i in range(5):
+ f.write("%d\n" % i)
+ finally:
+ f.close()
+ f = open(TESTFN, "r")
+ try:
+ self.assertEqual(tuple(f), ("0\n", "1\n", "2\n", "3\n", "4\n"))
+ f.seek(0, 0)
+ self.assertEqual(tuple(f.xreadlines()),
+ ("0\n", "1\n", "2\n", "3\n", "4\n"))
+ finally:
+ f.close()
+ try:
+ unlink(TESTFN)
+ except OSError:
+ pass
+
# Test filter()'s use of iterators.
def test_builtin_filter(self):
self.assertEqual(filter(None, SequenceClass(5)), range(1, 5))