Allow subscript splitting around and/or ops

The LHS and RHS of the ops are still left contiguous, but loosen the
restriction when it's and/or ops.

Closes #332

CHANGELOG

@@ -9,6 +9,8 @@
   split here:
 
       func(a, b, c, d(x, y, z=42))
+- Allow splitting inside a subscript if it's a logical or bitwise operating.
+  This should keep the subscript mostly contiguous otherwise.
 
 ## [0.15.1] 2017-01-21
 ### Fixed

yapf/yapflib/split_penalty.py

@@ -166,15 +166,34 @@ def Visit_trailer(self, node):  # pylint: disable=invalid-name
           pytree_utils.SetNodeAnnotation(
               _FirstChildNode(node.children[1]),
               pytree_utils.Annotation.SPLIT_PENALTY, ONE_ELEMENT_ARGUMENT)
+      elif (pytree_utils.NodeName(node.children[0]) == 'LSQB' and
+            (name.endswith('_test') or name.endswith('_expr'))):
+        self._SetStronglyConnected(node.children[1].children[0])
+        self._SetStronglyConnected(node.children[1].children[2])
+
+        # Still allow splitting around the operator.
+        split_before = (
+            (name.endswith('_test') and
+             style.Get('SPLIT_BEFORE_LOGICAL_OPERATOR')) or
+            (name.endswith('_expr') and
+             style.Get('SPLIT_BEFORE_BITWISE_OPERATOR')))
+        if split_before:
+          pytree_utils.SetNodeAnnotation(
+              _LastChildNode(node.children[1].children[1]),
+              pytree_utils.Annotation.SPLIT_PENALTY, 0)
+        else:
+          pytree_utils.SetNodeAnnotation(
+              _FirstChildNode(node.children[1].children[2]),
+              pytree_utils.Annotation.SPLIT_PENALTY, 0)
+
+        # Don't split the ending bracket of a subscript list.
+        self._SetVeryStronglyConnected(node.children[-1])
       elif name not in {
           'arglist', 'argument', 'term', 'or_test', 'and_test', 'comparison',
           'atom'
       }:
         # Don't split an argument list with one element if at all possible.
         self._SetStronglyConnected(node.children[1], node.children[2])
-      if pytree_utils.NodeName(node.children[-1]) == 'RSQB':
-        # Don't split the ending bracket of a subscript list.
-        self._SetVeryStronglyConnected(*node.children)
 
   def Visit_power(self, node):  # pylint: disable=invalid-name,missing-docstring
     # power ::= atom trailer* ['**' factor]

yapftests/reformatter_pep8_test.py

@@ -296,6 +296,19 @@ def testSplittingBeforeFirstArgument(self):
     finally:
       style.SetGlobalStyle(style.CreatePEP8Style())
 
+  def testSplittingExpressionsInsideSubscripts(self):
+    unformatted_code = textwrap.dedent("""\
+        def foo():
+            df = df[(df['campaign_status'] == 'LIVE') & (df['action_status'] == 'LIVE')]
+        """)
+    expected_formatted_code = textwrap.dedent("""\
+        def foo():
+            df = df[(df['campaign_status'] == 'LIVE') &
+                    (df['action_status'] == 'LIVE')]
+        """)
+    uwlines = yapf_test_helper.ParseAndUnwrap(unformatted_code)
+    self.assertCodeEqual(expected_formatted_code, reformatter.Reformat(uwlines))
+
 
 if __name__ == '__main__':
   unittest.main()