jinja2: fix default context (range missing, Py2/Py3 inconsistencies)

slapos/recipe/template/jinja2_template.py

@@ -35,8 +35,17 @@ from . import Recipe
 DEFAULT_CONTEXT = {x.__name__: x for x in (
     abs, all, any, bin, bool, bytes, callable, chr, complex, dict, divmod,
     enumerate, filter, float, format, frozenset, hex, int,
-  isinstance, iter, len, list, map, max, min, next, oct, ord,
-  pow, repr, reversed, round, set, six, sorted, str, sum, tuple, zip)}
+    isinstance, iter, len, list, map, max, min, next, oct, ord, pow,
+    range, repr, reversed, round, set, six, sorted, str, sum, tuple, zip)}
+
+if six.PY2:
+    import itertools
+    DEFAULT_CONTEXT.update(
+        filter=itertools.ifilter,
+        map=itertools.imap,
+        range=xrange,
+        zip=itertools.izip,
+    )
 
 def _assert(x, *args):
     if x: