Implement optional initial value for #86

Additionally update package info and have run-tests explicitly use
python 2

functional/__init__.py

@@ -7,9 +7,9 @@
 from functional.streams import seq, pseq
 
 __author__ = "Pedro Rodriguez"
-__copyright__ = "Copyright 2015, Pedro Rodriguez"
+__copyright__ = "Copyright 2016, Pedro Rodriguez"
 __license__ = "MIT"
-__version__ = "0.5.0"
+__version__ = "0.8.0"
 __maintainer__ = "Pedro Rodriguez"
 __email__ = "[email protected]"
-__status__ = "Development"
+__status__ = "Production"

functional/pipeline.py

@@ -874,17 +874,23 @@ def reduce_by_key(self, func):
         """
         return self._transform(transformations.reduce_by_key_t(func))
 
-    def reduce(self, func):
+    def reduce(self, func, *initial):
         """
-        Reduce sequence of elements using func.
+        Reduce sequence of elements using func. API mirrors functools.reduce
 
         >>> seq([1, 2, 3]).reduce(lambda x, y: x + y)
         6
 
         :param func: two parameter, associative reduce function
+        :param initial: single optional argument acting as initial value
         :return: reduced value using func
         """
-        return _wrap(reduce(func, self))
+        if len(initial) == 0:
+            return _wrap(reduce(func, self))
+        elif len(initial) == 1:
+            return _wrap(reduce(func, self, initial[0]))
+        else:
+            raise ValueError('reduce takes exactly one optional parameter for initial value')
 
     def make_string(self, separator):
         """

functional/test/test_functional.py

@@ -311,6 +311,14 @@ def test_reduce(self):
         s = self.seq(l)
         self.assertEqual(expect, s.reduce(f))
 
+        with self.assertRaises(TypeError):
+            seq([]).reduce(f)
+        with self.assertRaises(ValueError):
+            seq([]).reduce(f, 0, 0)
+
+        self.assertEqual(seq([]).reduce(f, 1), 1)
+        self.assertEqual(seq([0, 2]).reduce(f, 1), 3)
+
     def test_aggregate(self):
         f = lambda current, next_element: current + next_element
         l = self.seq([1, 2, 3, 4])

run-tests.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 echo "Running Python 2 Tests"
-python -m 'nose' --with-coverage --cover-package=functional --cover-erase
+python2 -m 'nose' --with-coverage --cover-package=functional --cover-erase
 sleep 1
 echo "Running Python 3 Tests"
 python3 -m 'nose' --with-coverage --cover-package=functional --cover-erase