handle switch from generator next() to __next__()

saucebrush/filters.py

@@ -301,7 +301,11 @@ class FieldAdder(Filter):
         self._field_name = field_name
         self._field_value = field_value
         if hasattr(self._field_value, '__iter__'):
-            self._field_value = iter(self._field_value).next
+            value_iter = iter(self._field_value)
+            if hasattr(value_iter, "next"):
+                self._field_value = value_iter.next
+            else:
+                self._field_value = value_iter.__next__
         self._replace = replace
 
     def process_record(self, record):

saucebrush/sources.py

@@ -59,13 +59,18 @@ class FixedWidthFileSource(object):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
-        line = self._fwfile.next()
+        line = next(self._fwfile)
         record = {}
         for name, range_ in self._fields_dict.items():
             record[name] = line[range_[0]:range_[1]].rstrip(self._fillchars)
         return record
 
+    def next(self):
+        """ Keep Python 2 next() method that defers to __next__().
+        """
+        return self.__next__()
+
 
 class HtmlTableSource(object):
     """ Saucebrush source for reading data from an HTML table.

saucebrush/tests/filters.py

@@ -63,7 +63,8 @@ class FilterTestCase(unittest.TestCase):
         recipe = DummyRecipe()
         f = Doubler()
         result = f.attach([1,2,3], recipe=recipe)
-        result.next()       # next has to be called for attach to take effect
+        # next has to be called for attach to take effect
+        next(result)
         f.reject_record('bad', 'this one was bad')
 
         # ensure that the rejection propagated to the recipe