Fixes for shared 2.6 code that implements PEP 3101, advanced string

formatting.

Includes:
 - Modifying tests for basic types to use __format__ methods, instead
   of builtin "format".
 - Adding PyObject_Format.
 - General str/unicode cleanup discovered when backporting to 2.6.
 - Removing datetimemodule.c's time_format, since it was identical
   to date_format.

The files in Objects/stringlib that implement PEP 3101 (stringdefs.h,
unicodedefs.h, formatter.h, string_format.h) are identical in trunk
and py3k.  Any changes from here on should be made to trunk, and
changes will propogate to py3k).

2 files changed, 79 insertions, 38 deletions

diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index 762afad..42c55cc 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -541,24 +541,58 @@ class BuiltinTest(unittest.TestCase):
         self.assertRaises(TypeError, float, Foo4(42))
 
     def test_format(self):
-        class A:
-            def __init__(self, x):
-                self.x = x
-            def __format__(self, format_spec):
-                return str(self.x) + format_spec
+        # Test the basic machinery of the format() builtin.  Don't test
+        #  the specifics of the various formatters
+        self.assertEqual(format(3, ''), '3')
 
-        # class that returns a bad type from __format__
-        class B:
-            def __format__(self, format_spec):
-                return 1.0
+        # Returns some classes to use for various tests.  There's
+        #  an old-style version, and a new-style version
+        def classes_new():
+            class A(object):
+                def __init__(self, x):
+                    self.x = x
+                def __format__(self, format_spec):
+                    return str(self.x) + format_spec
+            class DerivedFromA(A):
+                pass
 
-        # class that is derived from string, used
-        #  as a format spec
-        class C(str):
-            pass
+            class Simple(object): pass
+            class DerivedFromSimple(Simple):
+                def __init__(self, x):
+                    self.x = x
+                def __format__(self, format_spec):
+                    return str(self.x) + format_spec
+            class DerivedFromSimple2(DerivedFromSimple): pass
+            return A, DerivedFromA, DerivedFromSimple, DerivedFromSimple2
+
+        # In 3.0, classes_classic has the same meaning as classes_new
+        def classes_classic():
+            class A:
+                def __init__(self, x):
+                    self.x = x
+                def __format__(self, format_spec):
+                    return str(self.x) + format_spec
+            class DerivedFromA(A):
+                pass
 
-        self.assertEqual(format(3, ''), '3')
-        self.assertEqual(format(A(3), 'spec'), '3spec')
+            class Simple: pass
+            class DerivedFromSimple(Simple):
+                def __init__(self, x):
+                    self.x = x
+                def __format__(self, format_spec):
+                    return str(self.x) + format_spec
+            class DerivedFromSimple2(DerivedFromSimple): pass
+            return A, DerivedFromA, DerivedFromSimple, DerivedFromSimple2
+
+        def class_test(A, DerivedFromA, DerivedFromSimple, DerivedFromSimple2):
+            self.assertEqual(format(A(3), 'spec'), '3spec')
+            self.assertEqual(format(DerivedFromA(4), 'spec'), '4spec')
+            self.assertEqual(format(DerivedFromSimple(5), 'abc'), '5abc')
+            self.assertEqual(format(DerivedFromSimple2(10), 'abcdef'),
+                             '10abcdef')
+
+        class_test(*classes_new())
+        class_test(*classes_classic())
 
         def empty_format_spec(value):
             # test that:
@@ -578,19 +612,28 @@ class BuiltinTest(unittest.TestCase):
         empty_format_spec(None)
 
         # TypeError because self.__format__ returns the wrong type
-        self.assertRaises(TypeError, format, B(), "")
+        class BadFormatResult:
+            def __format__(self, format_spec):
+                return 1.0
+        self.assertRaises(TypeError, format, BadFormatResult(), "")
 
-        # TypeError because format_spec is not unicode
+        # TypeError because format_spec is not unicode or str
         self.assertRaises(TypeError, format, object(), 4)
         self.assertRaises(TypeError, format, object(), object())
 
+        # tests for object.__format__ really belong elsewhere, but
+        #  there's no good place to put them
+        x = object().__format__('')
+        self.assert_(x.startswith('<object object at'))
+
         # first argument to object.__format__ must be string
         self.assertRaises(TypeError, object().__format__, 3)
         self.assertRaises(TypeError, object().__format__, object())
         self.assertRaises(TypeError, object().__format__, None)
 
         # make sure we can take a subclass of str as a format spec
-        self.assertEqual(format(0, C('10')), '         0')
+        class DerivedFromStr(str): pass
+        self.assertEqual(format(0, DerivedFromStr('10')), '         0')
 
     def test_floatasratio(self):
         for f, ratio in [
diff --git a/Lib/test/test_datetime.py b/Lib/test/test_datetime.py
index 7c08f9e..8ac7160 100644
--- a/Lib/test/test_datetime.py
+++ b/Lib/test/test_datetime.py
@@ -851,29 +851,29 @@ class TestDate(HarmlessMixedComparison, unittest.TestCase):
 
     def test_format(self):
         dt = self.theclass(2007, 9, 10)
-        self.assertEqual(format(dt, ''), str(dt))
+        self.assertEqual(dt.__format__(''), str(dt))
 
         # check that a derived class's __str__() gets called
         class A(self.theclass):
             def __str__(self):
                 return 'A'
         a = A(2007, 9, 10)
-        self.assertEqual(format(a, ''), 'A')
+        self.assertEqual(a.__format__(''), 'A')
 
         # check that a derived class's strftime gets called
         class B(self.theclass):
             def strftime(self, format_spec):
                 return 'B'
         b = B(2007, 9, 10)
-        self.assertEqual(format(b, ''), str(dt))
+        self.assertEqual(b.__format__(''), str(dt))
 
         for fmt in ["m:%m d:%d y:%y",
                     "m:%m d:%d y:%y H:%H M:%M S:%S",
                     "%z %Z",
                     ]:
-            self.assertEqual(format(dt, fmt), dt.strftime(fmt))
-            self.assertEqual(format(a, fmt), dt.strftime(fmt))
-            self.assertEqual(format(b, fmt), 'B')
+            self.assertEqual(dt.__format__(fmt), dt.strftime(fmt))
+            self.assertEqual(a.__format__(fmt), dt.strftime(fmt))
+            self.assertEqual(b.__format__(fmt), 'B')
 
     def test_resolution_info(self):
         self.assert_(isinstance(self.theclass.min, self.theclass))
@@ -1178,31 +1178,29 @@ class TestDateTime(TestDate):
 
     def test_format(self):
         dt = self.theclass(2007, 9, 10, 4, 5, 1, 123)
-        self.assertEqual(format(dt, ''), str(dt))
+        self.assertEqual(dt.__format__(''), str(dt))
 
         # check that a derived class's __str__() gets called
         class A(self.theclass):
             def __str__(self):
                 return 'A'
         a = A(2007, 9, 10, 4, 5, 1, 123)
-        self.assertEqual(format(a, ''), 'A')
+        self.assertEqual(a.__format__(''), 'A')
 
         # check that a derived class's strftime gets called
         class B(self.theclass):
             def strftime(self, format_spec):
                 return 'B'
         b = B(2007, 9, 10, 4, 5, 1, 123)
-        self.assertEqual(format(b, ''), str(dt))
+        self.assertEqual(b.__format__(''), str(dt))
 
         for fmt in ["m:%m d:%d y:%y",
                     "m:%m d:%d y:%y H:%H M:%M S:%S",
                     "%z %Z",
                     ]:
-            self.assertEqual(format(dt, fmt), dt.strftime(fmt))
-            self.assertEqual(format(a, fmt), dt.strftime(fmt))
-            self.assertEqual(format(b, fmt), 'B')
-
-
+            self.assertEqual(dt.__format__(fmt), dt.strftime(fmt))
+            self.assertEqual(a.__format__(fmt), dt.strftime(fmt))
+            self.assertEqual(b.__format__(fmt), 'B')
 
     def test_more_ctime(self):
         # Test fields that TestDate doesn't touch.
@@ -1837,27 +1835,27 @@ class TestTime(HarmlessMixedComparison, unittest.TestCase):
 
     def test_format(self):
         t = self.theclass(1, 2, 3, 4)
-        self.assertEqual(format(t, ''), str(t))
+        self.assertEqual(t.__format__(''), str(t))
 
         # check that a derived class's __str__() gets called
         class A(self.theclass):
             def __str__(self):
                 return 'A'
         a = A(1, 2, 3, 4)
-        self.assertEqual(format(a, ''), 'A')
+        self.assertEqual(a.__format__(''), 'A')
 
         # check that a derived class's strftime gets called
         class B(self.theclass):
             def strftime(self, format_spec):
                 return 'B'
         b = B(1, 2, 3, 4)
-        self.assertEqual(format(b, ''), str(t))
+        self.assertEqual(b.__format__(''), str(t))
 
         for fmt in ['%H %M %S',
                     ]:
-            self.assertEqual(format(t, fmt), t.strftime(fmt))
-            self.assertEqual(format(a, fmt), t.strftime(fmt))
-            self.assertEqual(format(b, fmt), 'B')
+            self.assertEqual(t.__format__(fmt), t.strftime(fmt))
+            self.assertEqual(a.__format__(fmt), t.strftime(fmt))
+            self.assertEqual(b.__format__(fmt), 'B')
 
     def test_str(self):
         self.assertEqual(str(self.theclass(1, 2, 3, 4)), "01:02:03.000004")