Merged revisions 82262,82269,82434,82480-82481,82484-82485,82487-82488,82594,82599,82615 via svnmerge from
svn+ssh://svn.python.org/python/branches/py3k

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  r82262 | georg.brandl | 2010-06-27 12:17:12 +0200 (So, 27 Jun 2010) | 1 line

  #9078: fix some Unicode C API descriptions, in comments and docs.
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  r82269 | georg.brandl | 2010-06-27 12:59:19 +0200 (So, 27 Jun 2010) | 1 line

  Wording fix.
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  r82434 | georg.brandl | 2010-07-02 09:41:51 +0200 (Fr, 02 Jul 2010) | 9 lines

  Merged revisions 82433 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

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    r82433 | georg.brandl | 2010-07-02 09:33:50 +0200 (Fr, 02 Jul 2010) | 1 line

    Grammar and markup fixes.
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  r82480 | georg.brandl | 2010-07-03 12:21:50 +0200 (Sa, 03 Jul 2010) | 1 line

  Wrap and use the correct directive.
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  r82481 | georg.brandl | 2010-07-03 12:22:10 +0200 (Sa, 03 Jul 2010) | 1 line

  Use the right role.
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  r82484 | georg.brandl | 2010-07-03 12:26:17 +0200 (Sa, 03 Jul 2010) | 9 lines

  Recorded merge of revisions 82474 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

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    r82474 | georg.brandl | 2010-07-03 10:40:13 +0200 (Sa, 03 Jul 2010) | 1 line

    Fix role name.
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  r82485 | georg.brandl | 2010-07-03 12:26:54 +0200 (Sa, 03 Jul 2010) | 9 lines

  Merged revisions 82483 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

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    r82483 | georg.brandl | 2010-07-03 12:25:54 +0200 (Sa, 03 Jul 2010) | 1 line

    Add link to bytecode docs.
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  r82487 | georg.brandl | 2010-07-03 12:33:26 +0200 (Sa, 03 Jul 2010) | 1 line

  Fix markup.
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  r82488 | georg.brandl | 2010-07-03 12:41:33 +0200 (Sa, 03 Jul 2010) | 1 line

  Remove the need for a "()" empty argument list after opcodes.
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  r82594 | georg.brandl | 2010-07-05 22:13:41 +0200 (Mo, 05 Jul 2010) | 1 line

  Update Vec class constructor, remove indirection via function, use operator module.
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  r82599 | alexander.belopolsky | 2010-07-05 23:44:05 +0200 (Mo, 05 Jul 2010) | 1 line

  "Modernized" the demo a little.
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  r82615 | georg.brandl | 2010-07-07 00:58:50 +0200 (Mi, 07 Jul 2010) | 1 line

  Fix typo.
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diff --git a/Demo/classes/Vec.py b/Demo/classes/Vec.py
index edb3147..787af69 100755
--- a/Demo/classes/Vec.py
+++ b/Demo/classes/Vec.py
@@ -1,23 +1,41 @@
-# A simple vector class
-
-
-def vec(*v):
-    return Vec(*v)
-
-
 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)
 
-    def fromlist(self, v):
+    @classmethod
+    def fromlist(cls, v):
         if not isinstance(v, list):
             raise TypeError
-        self.v = v[:]
-        return self
+        inst = cls()
+        inst.v = v
+        return inst
 
     def __repr__(self):
-        return 'vec(' + repr(self.v)[1:-1] + ')'
+        args = ', '.join(repr(x) for x in self.v)
+        return 'Vec({})'.format(args)
 
     def __len__(self):
         return len(self.v)
@@ -27,28 +45,24 @@
 
     def __add__(self, other):
         # Element-wise addition
-        v = list(map(lambda x, y: x+y, self, other))
-        return Vec().fromlist(v)
+        v = [x + y for x, y in zip(self.v, other.v)]
+        return Vec.fromlist(v)
 
     def __sub__(self, other):
         # Element-wise subtraction
-        v = list(map(lambda x, y: x-y, self, other))
-        return Vec().fromlist(v)
+        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)
+        v = [x * scalar for x in self.v]
+        return Vec.fromlist(v)
 
+    __rmul__ = __mul__
 
 
 def test():
-    a = vec(1, 2, 3)
-    b = vec(3, 2, 1)
-    print(a)
-    print(b)
-    print(a+b)
-    print(a-b)
-    print(a*3.0)
+    import doctest
+    doctest.testmod()
 
 test()