REF: BaseIterator for parsers' common logic

Author: toobaz

pandas/io/common.py

@@ -9,7 +9,7 @@
 
 from pandas.compat import StringIO, BytesIO, string_types, text_type
 from pandas import compat
-from pandas.core.common import pprint_thing, is_number
+from pandas.core.common import pprint_thing, is_number, AbstractMethodError
 
 
 try:
@@ -59,6 +59,20 @@ class DtypeWarning(Warning):
     pass
 
 
+class BaseIterator(object):
+    """Subclass this and provide a "__next__()" method to obtain an iterator.
+    Useful only when the object being iterated is non-reusable (e.g. OK for a
+    parser, not for an in-memory table, yes for its iterator)."""
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        raise AbstractMethodError(self)
+
+if not compat.PY3:
+    BaseIterator.next = lambda self: self.__next__()
+
+
 try:
     from boto.s3 import key