to allow "default" parameter in min and max issue 334

src/future/builtins/__init__.py

@@ -11,7 +11,7 @@
 # The isinstance import is no longer needed. We provide it only for
 # backward-compatibility with future v0.8.2. It will be removed in future v1.0.
 from future.builtins.misc import (ascii, chr, hex, input, isinstance, next,
-                                  oct, open, pow, round, super)
+                                  oct, open, pow, round, super, max, min)
 from future.utils import PY3
 
 if PY3:
@@ -43,7 +43,7 @@
     __all__ = ['filter', 'map', 'zip',
                'ascii', 'chr', 'hex', 'input', 'next', 'oct', 'open', 'pow',
                'round', 'super',
-               'bytes', 'dict', 'int', 'list', 'object', 'range', 'str',
+               'bytes', 'dict', 'int', 'list', 'object', 'range', 'str', 'max', 'min'
               ]
 
 else:

src/future/builtins/misc.py

@@ -13,6 +13,8 @@
 - ``open`` (equivalent to io.open on Py2)
 - ``super`` (backport of Py3's magic zero-argument super() function
 - ``round`` (new "Banker's Rounding" behaviour from Py3)
+- ``max`` (new default option from Py3.4)
+- ``min`` (new default option from Py3.4)
 
 ``isinstance`` is also currently exported for backwards compatibility
 with v0.8.2, although this has been deprecated since v0.9.
@@ -59,6 +61,8 @@
     from future.builtins.newnext import newnext as next
     from future.builtins.newround import newround as round
     from future.builtins.newsuper import newsuper as super
+    from future.builtins.new_min_max import newmax as max
+    from future.builtins.new_min_max import newmin as min
     from future.types.newint import newint
 
     _SENTINEL = object()
@@ -89,11 +93,12 @@ def pow(x, y, z=_SENTINEL):
             else:
                 return _builtin_pow(x+0j, y, z)
 
+
     # ``future`` doesn't support Py3.0/3.1. If we ever did, we'd add this:
     #     callable = __builtin__.callable
 
     __all__ = ['ascii', 'chr', 'hex', 'input', 'isinstance', 'next', 'oct',
-               'open', 'pow', 'round', 'super']
+               'open', 'pow', 'round', 'super', 'max', 'min']
 
 else:
     import builtins
@@ -109,8 +114,14 @@ def pow(x, y, z=_SENTINEL):
     pow = builtins.pow
     round = builtins.round
     super = builtins.super
-
-    __all__ = []
+    if utils.PY34_PLUS:
+        max = builtins.max
+        min = builtins.min
+        __all__ = []
+    else:
+        from future.builtins.new_min_max import newmax as max
+        from future.builtins.new_min_max import newmin as min
+        __all__ = ['min', 'max']
 
     # The callable() function was removed from Py3.0 and 3.1 and
     # reintroduced into Py3.2+. ``future`` doesn't support Py3.0/3.1. If we ever

src/future/builtins/new_min_max.py

@@ -0,0 +1,52 @@
+from future import utils
+if utils.PY2:
+    from __builtin__ import max as _builtin_max, min as _builtin_min
+else:
+    from builtins import max as _builtin_max, min as _builtin_min
+
+
+def newmin(*args, **kwargs):
+    return new_min_max(_builtin_min, *args, **kwargs)
+
+
+def newmax(*args, **kwargs):
+    return new_min_max(_builtin_max, *args, **kwargs)
+
+
+def new_min_max(_builtin_func, *args, **kwargs):
+    """
+    To support the argument "default" introduced in python 3.4 for min and max
+    :param _builtin_func: builtin min or builtin max
+    :param args:
+    :param kwargs:
+    :return: returns the min or max based on the arguments passed
+    """
+
+    for key, _ in kwargs.items():
+        if key not in set(['key', 'default']):
+            raise TypeError('Illegal argument %s', key)
+
+    if len(args) == 0:
+        raise TypeError
+
+    if len(args) != 1 and kwargs.get('default') is not None:
+        raise TypeError
+
+    if len(args) == 1:
+        try:
+            next(iter(args[0]))
+        except StopIteration:
+            if kwargs.get('default') is not None:
+                return kwargs.get('default')
+            else:
+                raise ValueError('iterable is an empty sequence')
+        if kwargs.get('key') is not None:
+            return _builtin_func(args[0], key=kwargs.get('key'))
+        else:
+            return _builtin_func(args[0])
+
+    if len(args) > 1:
+        if kwargs.get('key') is not None:
+            return _builtin_func(args, key=kwargs.get('key'))
+        else:
+            return _builtin_func(args)

src/future/utils/__init__.py

@@ -56,6 +56,7 @@
 
 
 PY3 = sys.version_info[0] >= 3
+PY34_PLUS = sys.version_info[0:2] >= (3, 4)
 PY35_PLUS = sys.version_info[0:2] >= (3, 5)
 PY36_PLUS = sys.version_info[0:2] >= (3, 6)
 PY2 = sys.version_info[0] == 2

tests/test_future/test_builtins.py

@@ -6,7 +6,7 @@
 from __future__ import absolute_import, division, print_function, unicode_literals
 from future.builtins import (bytes, dict, int, range, round, str, super,
                              ascii, chr, hex, input, next, oct, open, pow,
-                             filter, map, zip)
+                             filter, map, zip, min, max)
 
 from future.utils import PY3, exec_, native_str, implements_iterator
 from future.tests.base import (unittest, skip26, expectedFailurePY2,
@@ -1099,6 +1099,13 @@ def test_max(self):
         self.assertEqual(max(data, key=f),
                          sorted(reversed(data), key=f)[-1])
 
+        self.assertEqual(max([], default=5), 5)
+        with self.assertRaises(TypeError):
+            max(None, default=5)
+        with self.assertRaises(TypeError):
+            max(1, 2, default=0)
+        self.assertEqual(max([], default=0), 0)
+
     def test_min(self):
         self.assertEqual(min('123123'), '1')
         self.assertEqual(min(1, 2, 3), 1)
@@ -1140,6 +1147,12 @@ def __getitem__(self, index):
         f = keys.__getitem__
         self.assertEqual(min(data, key=f),
                          sorted(data, key=f)[0])
+        self.assertEqual(min([], default=5), 5)
+        self.assertEqual(min([], default=0), 0)
+        with self.assertRaises(TypeError):
+            max(None, default=5)
+        with self.assertRaises(TypeError):
+            max(1, 2, default=0)
 
     def test_next(self):
         it = iter(range(2))