Add Python 3 support.

optimize_later/config.py

@@ -1,7 +1,7 @@
 import logging
 from functools import wraps
 
-from optimize_later.utils import NoArgDecoratorMeta
+from optimize_later.utils import NoArgDecoratorMeta, with_metaclass
 
 try:
     import threading
@@ -38,9 +38,7 @@ def global_callback(report):
             log.exception('Failed to invoke global callback: %r', callback)
 
 
-class optimize_context(object):
-    __metaclass__ = NoArgDecoratorMeta
-
+class optimize_context(with_metaclass(NoArgDecoratorMeta)):
     def __init__(self, callbacks=None):
         self.callbacks = callbacks
 

optimize_later/core.py

@@ -7,7 +7,7 @@ from functools import wraps
 from numbers import Number
 
 from optimize_later.config import global_callback
-from optimize_later.utils import NoArgDecoratorMeta
+from optimize_later.utils import NoArgDecoratorMeta, with_metaclass
 
 log = logging.getLogger(__name__.rpartition('.')[0] or __name__)
 timer = [time.time, time.clock][os.name == 'nt']
@@ -89,9 +89,7 @@ class OptimizeReport(object):
         return self.short()
 
 
-class optimize_later(object):
-    __metaclass__ = NoArgDecoratorMeta
-
+class optimize_later(with_metaclass(NoArgDecoratorMeta)):
     def __init__(self, name=None, limit=None, callback=None):
         if limit is None and isinstance(name, Number):
             name, limit = None, name

optimize_later/tests.py

@@ -162,7 +162,7 @@ class OptimizeLaterTest(TestCase):
         self.assertEqual(len(reports), 1)
         self.assertReport(reports[0], blocks=2)
         report = reports[0].long()
-        print report
+        print(report)
         self.assertIn('      - Block ', report)
         self.assertIn('  - Block', report)
         self.assertEqual(report.count(', children:'), 2)
@@ -177,7 +177,7 @@ class OptimizeLaterTest(TestCase):
         self.assertEqual(function.__name__, 'function')
         self.assertEqual(function.__module__, __name__)
 
-        for i in xrange(10):
+        for i in range(10):
             function()
         self.assertEqual(len(reports), 10)
         for report in reports:

optimize_later/utils.py

@@ -6,3 +6,17 @@ class NoArgDecoratorMeta(type):
         if len(args) == 1 and isinstance(args[0], FunctionType):
             return cls()(args[0])
         return super(NoArgDecoratorMeta, cls).__call__(*args, **kwargs)
+
+
+# Borrowed from the six library.
+def with_metaclass(meta, *bases):
+    """Create a base class with a metaclass."""
+
+    # This requires a bit of explanation: the basic idea is to make a dummy
+    # metaclass for one level of class instantiation that replaces itself with
+    # the actual metaclass.
+    class metaclass(meta):
+        def __new__(cls, name, this_bases, d):
+            return meta(name, bases, d)
+
+    return type.__new__(metaclass, 'temporary_class', (), {})