Generalize dictionary() to accept a sequence of 2-sequences. At the
outer level, the iterator protocol is used for memory-efficiency (the
outer sequence may be very large if fully materialized); at the inner
level, PySequence_Fast() is used for time-efficiency (these should
always be sequences of length 2).
dictobject.c, new functions PyDict_{Merge,Update}FromSeq2. These are
wholly analogous to PyDict_{Merge,Update}, but process a sequence-of-2-
sequences argument instead of a mapping object. For now, I left these
functions file static, so no corresponding doc changes. It's tempting
to change dict.update() to allow a sequence-of-2-seqs argument too.
Also changed the name of dictionary's keyword argument from "mapping"
to "x". Got a better name? "mapping_or_sequence_of_pairs" isn't
attractive, although more so than "mosop" <wink>.
abstract.h, abstract.tex: Added new PySequence_Fast_GET_SIZE function,
much faster than going thru the all-purpose PySequence_Size.
libfuncs.tex:
- Document dictionary().
- Fiddle tuple() and list() to admit that their argument is optional.
- The long-winded repetitions of "a sequence, a container that supports
iteration, or an iterator object" is getting to be a PITA. Many
months ago I suggested factoring this out into "iterable object",
where the definition of that could include being explicit about
generators too (as is, I'm not sure a reader outside of PythonLabs
could guess that "an iterator object" includes a generator call).
- Please check my curly braces -- I'm going blind <0.9 wink>.
abstract.c, PySequence_Tuple(): When PyObject_GetIter() fails, leave
its error msg alone now (the msg it produces has improved since
PySequence_Tuple was generalized to accept iterable objects, and
PySequence_Tuple was also stomping on the msg in cases it shouldn't
have even before PyObject_GetIter grew a better msg).
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 87f4f0f..230d6a1 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -178,15 +178,25 @@
vereq(d, {})
d = dictionary({})
vereq(d, {})
- d = dictionary(mapping={})
+ d = dictionary(x={})
vereq(d, {})
d = dictionary({1: 2, 'a': 'b'})
vereq(d, {1: 2, 'a': 'b'})
+ vereq(d, dictionary(d.items()))
+ vereq(d, dictionary(x=d.iteritems()))
for badarg in 0, 0L, 0j, "0", [0], (0,):
try:
dictionary(badarg)
except TypeError:
pass
+ except ValueError:
+ if badarg == "0":
+ # It's a sequence, and its elements are also sequences (gotta
+ # love strings <wink>), but they aren't of length 2, so this
+ # one seemed better as a ValueError than a TypeError.
+ pass
+ else:
+ raise TestFailed("no TypeError from dictionary(%r)" % badarg)
else:
raise TestFailed("no TypeError from dictionary(%r)" % badarg)
try:
@@ -194,7 +204,7 @@
except TypeError:
pass
else:
- raise TestFailed("no TypeError from dictionary(senseless={}")
+ raise TestFailed("no TypeError from dictionary(senseless={})")
try:
dictionary({}, {})
@@ -204,11 +214,9 @@
raise TestFailed("no TypeError from dictionary({}, {})")
class Mapping:
+ # Lacks a .keys() method; will be added later.
dict = {1:2, 3:4, 'a':1j}
- def __getitem__(self, i):
- return self.dict[i]
-
try:
dictionary(Mapping())
except TypeError:
@@ -217,9 +225,36 @@
raise TestFailed("no TypeError from dictionary(incomplete mapping)")
Mapping.keys = lambda self: self.dict.keys()
- d = dictionary(mapping=Mapping())
+ Mapping.__getitem__ = lambda self, i: self.dict[i]
+ d = dictionary(x=Mapping())
vereq(d, Mapping.dict)
+ # Init from sequence of iterable objects, each producing a 2-sequence.
+ class AddressBookEntry:
+ def __init__(self, first, last):
+ self.first = first
+ self.last = last
+ def __iter__(self):
+ return iter([self.first, self.last])
+
+ d = dictionary([AddressBookEntry('Tim', 'Warsaw'),
+ AddressBookEntry('Barry', 'Peters'),
+ AddressBookEntry('Tim', 'Peters'),
+ AddressBookEntry('Barry', 'Warsaw')])
+ vereq(d, {'Barry': 'Warsaw', 'Tim': 'Peters'})
+
+ d = dictionary(zip(range(4), range(1, 5)))
+ vereq(d, dictionary([(i, i+1) for i in range(4)]))
+
+ # Bad sequence lengths.
+ for bad in ['tooshort'], ['too', 'long', 'by 1']:
+ try:
+ dictionary(bad)
+ except ValueError:
+ pass
+ else:
+ raise TestFailed("no ValueError from dictionary(%r)" % bad)
+
def test_dir():
if verbose:
print "Testing dir() ..."
@@ -1830,7 +1865,7 @@
vereq(unicode(string='abc', errors='strict'), u'abc')
vereq(tuple(sequence=range(3)), (0, 1, 2))
vereq(list(sequence=(0, 1, 2)), range(3))
- vereq(dictionary(mapping={1: 2}), {1: 2})
+ vereq(dictionary(x={1: 2}), {1: 2})
for constructor in (int, float, long, complex, str, unicode,
tuple, list, dictionary, file):
@@ -2371,7 +2406,7 @@
vereq(f.__call__(a=42), 42)
a = []
list.__init__(a, sequence=[0, 1, 2])
- vereq(a, [0, 1, 2])
+ vereq(a, [0, 1, 2])
def test_main():
class_docstrings()