Update is_int function

1 files changed, 3 insertions, 1 deletions

diff --git a/functions.py b/functions.py
index b069581..7f8a552 100644
--- a/functions.py
+++ b/functions.py
@@ -254,12 +254,14 @@ def is_int(n):
     if type(n) in (types.IntType, types.LongType):
         return True
 
+    if isinstance(n, _Rational):
+        return (n.n == 0 or n.d == 1)
+
     if not isinstance(n, _Decimal):
         n = _d(n)
         if n is None:
             return False
 
-
     (sign, d, e) = n.normalize().as_tuple()
     return e >= 0
 is_int.__doc__ = ('is_int(n), determine whether n is an integer.')