Make xrange a numpy_expr.

Author: pbrunet

pythran/pythonic/include/__builtin__/xrange.hpp

@@ -51,6 +51,9 @@ namespace pythonic
       using const_iterator = xrange_iterator;
       using reverse_iterator = xrange_riterator;
       using const_reverse_iterator = xrange_riterator;
+      using dtype = value_type;
+      static constexpr bool is_vectorizable = false;
+      static constexpr size_t value = 1;
 
       long _begin;
       long _end;

pythran/pythonic/include/utils/numpy_traits.hpp

@@ -17,6 +17,11 @@ namespace pythonic
     }
   }
 
+  namespace __builtin__
+  {
+    struct xrange;
+  }
+
   namespace types
   {
 
@@ -144,6 +149,10 @@ namespace pythonic
     struct is_numexpr_arg<itertools::details::izip<F, V...>> : std::true_type {
     };
 
+    template <>
+    struct is_numexpr_arg<__builtin__::xrange> : std::true_type {
+    };
+
     template <class E>
     struct dtype_of {
       template <class T>

pythran/tests/test_numpy_func1.py

@@ -66,6 +66,13 @@ def np_sum_izip(a):
                 return np.sum(izip(a, a))
                       """, range(10), np_sum_izip=[[int]])
 
+    def test_sum_xrange(self):
+        self.run_test("""
+            def np_sum_xrange(a):
+                import numpy as np
+                return np.sum(xrange(a))
+                      """, 10, np_sum_xrange=[int])
+
     def test_prod_(self):
         """ Check prod function for numpy array. """
         self.run_test("""