python-3.6.zip added from Github

README.cosmo contains the necessary links.

third_party/python/Tools/demo/vector.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+
+"""
+A demonstration of classes and their special methods in Python.
+"""
+
+class Vec:
+    """A simple vector class.
+
+    Instances of the Vec class can be constructed from numbers
+
+    >>> a = Vec(1, 2, 3)
+    >>> b = Vec(3, 2, 1)
+
+    added
+    >>> a + b
+    Vec(4, 4, 4)
+
+    subtracted
+    >>> a - b
+    Vec(-2, 0, 2)
+
+    and multiplied by a scalar on the left
+    >>> 3.0 * a
+    Vec(3.0, 6.0, 9.0)
+
+    or on the right
+    >>> a * 3.0
+    Vec(3.0, 6.0, 9.0)
+    """
+    def __init__(self, *v):
+        self.v = list(v)
+
+    @classmethod
+    def fromlist(cls, v):
+        if not isinstance(v, list):
+            raise TypeError
+        inst = cls()
+        inst.v = v
+        return inst
+
+    def __repr__(self):
+        args = ', '.join(repr(x) for x in self.v)
+        return 'Vec({})'.format(args)
+
+    def __len__(self):
+        return len(self.v)
+
+    def __getitem__(self, i):
+        return self.v[i]
+
+    def __add__(self, other):
+        # Element-wise addition
+        v = [x + y for x, y in zip(self.v, other.v)]
+        return Vec.fromlist(v)
+
+    def __sub__(self, other):
+        # Element-wise subtraction
+        v = [x - y for x, y in zip(self.v, other.v)]
+        return Vec.fromlist(v)
+
+    def __mul__(self, scalar):
+        # Multiply by scalar
+        v = [x * scalar for x in self.v]
+        return Vec.fromlist(v)
+
+    __rmul__ = __mul__
+
+
+def test():
+    import doctest
+    doctest.testmod()
+
+test()