diff --git a/NEWS b/NEWS index 8ce77c49..adaa143a 100644 --- a/NEWS +++ b/NEWS @@ -13,6 +13,8 @@ Bug fixes: What's new in psycopg 2.5.3 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ +- Added arbitrary but stable order to `Range` objects, thanks to + Chris Withers (:ticket:`#193`). - Fixed debug build on Windows, thanks to James Emerton. diff --git a/doc/src/extras.rst b/doc/src/extras.rst index a0a2d1ca..7fab3384 100644 --- a/doc/src/extras.rst +++ b/doc/src/extras.rst @@ -437,8 +437,16 @@ user-defined |range| types can be adapted using `register_range()`. `!Range` objects are immutable, hashable, and support the ``in`` operator (checking if an element is within the range). They can be tested for - equivalence but not for ordering. Empty ranges evaluate to `!False` in - boolean context, nonempty evaluate to `!True`. + equivalence. Empty ranges evaluate to `!False` in boolean context, + nonempty evaluate to `!True`. + + .. versionchanged:: 2.5.3 + + `!Range` objects can be sorted although, as on the server-side, this + ordering is not particularly meangingful. It is only meant to be used + by programs assuming objects using `!Range` as primary key can be + sorted on them. In previous versions comparing `!Range`\s raises + `!TypeError`. Although it is possible to instantiate `!Range` objects, the class doesn't have an adapter registered, so you cannot normally pass these instances as diff --git a/lib/_range.py b/lib/_range.py index 45866392..47b82086 100644 --- a/lib/_range.py +++ b/lib/_range.py @@ -133,12 +133,43 @@ class Range(object): def __hash__(self): return hash((self._lower, self._upper, self._bounds)) - def __lt__(self, other): - raise TypeError( - 'Range objects cannot be ordered; please refer to the PostgreSQL' - ' documentation to perform this operation in the database') + # as the postgres docs describe for the server-side stuff, + # ordering is rather arbitrary, but will remain stable + # and consistent. - __le__ = __gt__ = __ge__ = __lt__ + def __lt__(self, other): + if not isinstance(other, Range): + return NotImplemented + for attr in ('_lower', '_upper', '_bounds'): + self_value = getattr(self, attr) + other_value = getattr(other, attr) + if self_value == other_value: + pass + elif self_value is None: + return True + elif other_value is None: + return False + else: + return self_value < other_value + return False + + def __le__(self, other): + if self == other: + return True + else: + return self.__lt__(other) + + def __gt__(self, other): + if isinstance(other, Range): + return other.__lt__(self) + else: + return NotImplemented + + def __ge__(self, other): + if self == other: + return True + else: + return self.__gt__(other) def register_range(pgrange, pyrange, conn_or_curs, globally=False): diff --git a/tests/test_types_extras.py b/tests/test_types_extras.py index 4fedd5ea..4625995d 100755 --- a/tests/test_types_extras.py +++ b/tests/test_types_extras.py @@ -13,6 +13,7 @@ # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or # FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public # License for more details. +from __future__ import with_statement import re import sys @@ -22,6 +23,7 @@ from functools import wraps from testutils import unittest, skip_if_no_uuid, skip_before_postgres from testutils import ConnectingTestCase, decorate_all_tests +from testutils import py3_raises_typeerror import psycopg2 import psycopg2.extras @@ -1236,12 +1238,73 @@ class RangeTestCase(unittest.TestCase): self.assertEqual(Range(10, 20), IntRange(10, 20)) self.assertEqual(PositiveIntRange(10, 20), IntRange(10, 20)) - def test_not_ordered(self): + # as the postgres docs describe for the server-side stuff, + # ordering is rather arbitrary, but will remain stable + # and consistent. + + def test_lt_ordering(self): from psycopg2.extras import Range - self.assertRaises(TypeError, lambda: Range(empty=True) < Range(0,4)) - self.assertRaises(TypeError, lambda: Range(1,2) > Range(0,4)) - self.assertRaises(TypeError, lambda: Range(1,2) <= Range()) - self.assertRaises(TypeError, lambda: Range(1,2) >= Range()) + self.assert_(Range(empty=True) < Range(0, 4)) + self.assert_(not Range(1, 2) < Range(0, 4)) + self.assert_(Range(0, 4) < Range(1, 2)) + self.assert_(not Range(1, 2) < Range()) + self.assert_(Range() < Range(1, 2)) + self.assert_(not Range(1) < Range(upper=1)) + self.assert_(not Range() < Range()) + self.assert_(not Range(empty=True) < Range(empty=True)) + self.assert_(not Range(1, 2) < Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(1 < Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(not Range(1, 2) < 1) + + def test_gt_ordering(self): + from psycopg2.extras import Range + self.assert_(not Range(empty=True) > Range(0, 4)) + self.assert_(Range(1, 2) > Range(0, 4)) + self.assert_(not Range(0, 4) > Range(1, 2)) + self.assert_(Range(1, 2) > Range()) + self.assert_(not Range() > Range(1, 2)) + self.assert_(Range(1) > Range(upper=1)) + self.assert_(not Range() > Range()) + self.assert_(not Range(empty=True) > Range(empty=True)) + self.assert_(not Range(1, 2) > Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(not 1 > Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(Range(1, 2) > 1) + + def test_le_ordering(self): + from psycopg2.extras import Range + self.assert_(Range(empty=True) <= Range(0, 4)) + self.assert_(not Range(1, 2) <= Range(0, 4)) + self.assert_(Range(0, 4) <= Range(1, 2)) + self.assert_(not Range(1, 2) <= Range()) + self.assert_(Range() <= Range(1, 2)) + self.assert_(not Range(1) <= Range(upper=1)) + self.assert_(Range() <= Range()) + self.assert_(Range(empty=True) <= Range(empty=True)) + self.assert_(Range(1, 2) <= Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(1 <= Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(not Range(1, 2) <= 1) + + def test_ge_ordering(self): + from psycopg2.extras import Range + self.assert_(not Range(empty=True) >= Range(0, 4)) + self.assert_(Range(1, 2) >= Range(0, 4)) + self.assert_(not Range(0, 4) >= Range(1, 2)) + self.assert_(Range(1, 2) >= Range()) + self.assert_(not Range() >= Range(1, 2)) + self.assert_(Range(1) >= Range(upper=1)) + self.assert_(Range() >= Range()) + self.assert_(Range(empty=True) >= Range(empty=True)) + self.assert_(Range(1, 2) >= Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(not 1 >= Range(1, 2)) + with py3_raises_typeerror(): + self.assert_(Range(1, 2) >= 1) def skip_if_no_range(f): diff --git a/tests/testutils.py b/tests/testutils.py index 708dd224..0569edef 100644 --- a/tests/testutils.py +++ b/tests/testutils.py @@ -329,3 +329,13 @@ def script_to_py3(script): f2.close() os.remove(filename) +class py3_raises_typeerror(object): + + def __enter__(self): + pass + + def __exit__(self, type, exc, tb): + if sys.version_info[0] >= 3: + assert type is TypeError + return True +