sync from Atlas repo

classes/vector_v6.py

@@ -1,5 +1,5 @@
 """
-A multi-dimensional ``Vector`` class, take 6
+A multi-dimensional ``Vector`` class, take 6: operator ``+``
 
 A ``Vector`` is built from an iterable of numbers::
 
@@ -183,19 +183,49 @@ Tests of ``format()`` with spherical coordinates in 2D, 3D and 4D::
     '<1.00000, 1.57080, 0.00000, 0.00000>'
 
 
-Tests of operator `==`::
+Basic tests of operator ``+``::
 
-    >>> v1 = Vector(range(1, 4))
-    >>> v2 = Vector([1.0, 2.0, 3.0])
-    >>> v1 == v2
+    >>> v1 = Vector([3, 4, 5])
+    >>> v2 = Vector([6, 7, 8])
+    >>> v1 + v2
+    Vector([9.0, 11.0, 13.0])
+    >>> v1 + v2 == Vector([3+6, 4+7, 5+8])
     True
+    >>> v3 = Vector([1, 2])
+    >>> v1 + v3  # short vectors are filled with 0.0 on addition
+    Vector([4.0, 6.0, 5.0])
+
+
+Tests of ``+`` with mixed types::
+
+    >>> v1 + (10, 20, 30)
+    Vector([13.0, 24.0, 35.0])
     >>> from vector2d_v3 import Vector2d
-    >>> Vector([7, 8]) == Vector2d(7, 8)
-    True
-    >>> v1 == (1, 2, 3)
-    False
+    >>> v2d = Vector2d(1, 2)
+    >>> v1 + v2d
+    Vector([4.0, 6.0, 5.0])
 
 
+Tests of ``+`` with mixed types, swapped operands::
+
+    >>> (10, 20, 30) + v1
+    Vector([13.0, 24.0, 35.0])
+    >>> from vector2d_v3 import Vector2d
+    >>> v2d = Vector2d(1, 2)
+    >>> v2d + v1
+    Vector([4.0, 6.0, 5.0])
+
+
+Tests of ``+`` with an unsuitable operand:
+
+    >>> v1 + 1
+    Traceback (most recent call last):
+      ...
+    TypeError: unsupported operand type(s) for +: 'Vector' and 'int'
+    >>> v1 + 'ABC'
+    Traceback (most recent call last):
+      ...
+    TypeError: unsupported operand type(s) for +: 'Vector' and 'str'
 """
 
 from array import array
@@ -227,14 +257,9 @@ class Vector:
         return (bytes([ord(self.typecode)]) +
                 bytes(self._components))
 
-# BEGIN VECTOR_V6_EQ
     def __eq__(self, other):
-        if isinstance(other, Vector):
-            return (len(self) == len(other) and
-                    all(a == b for a, b in zip(self, other)))
-        else:
-            return NotImplemented
-# END VECTOR_V6_EQ
+        return (len(self) == len(other) and
+                all(a == b for a, b in zip(self, other)))
 
     def __hash__(self):
         hashes = (hash(x) for x in self)
@@ -299,10 +324,14 @@ class Vector:
         memv = memoryview(octets[1:]).cast(typecode)
         return cls(memv)
 
+# BEGIN VECTOR_V6
     def __add__(self, other):
-        if len(self) != len(other):
-            cls_name = type(self).__name__
-            msg = 'cannot add {!r} of different dimensions'
-            raise ValueError(msg.format(cls_name))
-        return Vector(a + b for a, b in zip(self, other))
+        try:
+            pairs = itertools.zip_longest(self, other, fillvalue=0.0)
+            return Vector(a + b for a, b in pairs)
+        except TypeError:
+            return NotImplemented
 
+    def __radd__(self, other):
+        return self + other
+# END VECTOR_V6