From 8ec90443f57c13e895a43b0f62bdb73a6b30d552 Mon Sep 17 00:00:00 2001
From: Eric Smith <eric@trueblade.com>
Date: Sat, 14 Mar 2009 12:29:34 +0000
Subject: Merged revisions 70364 via svnmerge from
 svn+ssh://pythondev@svn.python.org/python/trunk

........
  r70364 | eric.smith | 2009-03-14 07:57:26 -0400 (Sat, 14 Mar 2009) | 17 lines

  Issue 5237, Allow auto-numbered replacement fields in str.format() strings.

  For simple uses for str.format(), this makes the typing easier. Hopfully this
  will help in the adoption of str.format().

  For example:
  'The {} is {}'.format('sky', 'blue')

  You can mix and matcth auto-numbering and named replacement fields:
  'The {} is {color}'.format('sky', color='blue')

  But you can't mix and match auto-numbering and specified numbering:
  'The {0} is {}'.format('sky', 'blue')
  ValueError: cannot switch from manual field specification to automatic field numbering

  Will port to 3.1.
........
---
 Lib/test/test_unicode.py | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

(limited to 'Lib/test/test_unicode.py')

diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index f16a78a303f..b40ee84708c 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -683,9 +683,9 @@ class UnicodeTest(
         self.assertRaises(ValueError, "{0!}".format, 0)
         self.assertRaises(ValueError, "{0!rs}".format, 0)
         self.assertRaises(ValueError, "{!}".format)
-        self.assertRaises(ValueError, "{:}".format)
-        self.assertRaises(ValueError, "{:s}".format)
-        self.assertRaises(ValueError, "{}".format)
+        self.assertRaises(IndexError, "{:}".format)
+        self.assertRaises(IndexError, "{:s}".format)
+        self.assertRaises(IndexError, "{}".format)
 
         # can't have a replacement on the field name portion
         self.assertRaises(TypeError, '{0[{1}]}'.format, 'abcdefg', 4)
@@ -704,6 +704,36 @@ class UnicodeTest(
         self.assertRaises(ValueError, format, '', '#')
         self.assertRaises(ValueError, format, '', '#20')
 
+    def test_format_auto_numbering(self):
+        class C:
+            def __init__(self, x=100):
+                self._x = x
+            def __format__(self, spec):
+                return spec
+
+        self.assertEqual('{}'.format(10), '10')
+        self.assertEqual('{:5}'.format('s'), 's    ')
+        self.assertEqual('{!r}'.format('s'), "'s'")
+        self.assertEqual('{._x}'.format(C(10)), '10')
+        self.assertEqual('{[1]}'.format([1, 2]), '2')
+        self.assertEqual('{[a]}'.format({'a':4, 'b':2}), '4')
+        self.assertEqual('a{}b{}c'.format(0, 1), 'a0b1c')
+
+        self.assertEqual('a{:{}}b'.format('x', '^10'), 'a    x     b')
+        self.assertEqual('a{:{}x}b'.format(20, '#'), 'a0x14b')
+
+        # can't mix and match numbering and auto-numbering
+        self.assertRaises(ValueError, '{}{1}'.format, 1, 2)
+        self.assertRaises(ValueError, '{1}{}'.format, 1, 2)
+        self.assertRaises(ValueError, '{:{1}}'.format, 1, 2)
+        self.assertRaises(ValueError, '{0:{}}'.format, 1, 2)
+
+        # can mix and match auto-numbering and named
+        self.assertEqual('{f}{}'.format(4, f='test'), 'test4')
+        self.assertEqual('{}{f}'.format(4, f='test'), '4test')
+        self.assertEqual('{:{f}}{g}{}'.format(1, 3, g='g', f=2), ' 1g3')
+        self.assertEqual('{f:{}}{}{g}'.format(2, 4, f=1, g='g'), ' 14g')
+
     def test_formatting(self):
         string_tests.MixinStrUnicodeUserStringTest.test_formatting(self)
         # Testing Unicode formatting strings...
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