Optimize splitting long, complex lines.

lib/src/line_splitting/rule_set.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-library dart_style.src.rule_set;
+library dart_style.src.line_splitting.rule_set;
 
-import 'rule/rule.dart';
+import '../rule/rule.dart';
 
 /// An optimized data structure for storing a set of values for some rules.
 ///
 /// This conceptually behaves roughly like a `Map<Rule, int>`, but is much
 /// faster since it avoids hashing. Instead, it assumes the line splitter has
 /// provided an ordered list of [Rule]s and that each rule's [index] field has
 /// been set to point to the rule in the list.
 ///
 /// Internally, this then just stores the values in a sparse list whose indices
 /// are the indices of the rules.
@@ skipping 130 matching lines @@
     var result = [];
     for (var i = 0; i < _columns.length; i++) {
       if (_columns[i] != null) {
         result.add("$i:${_columns[i]}");
       }
     }
 
     return result.join(" ");
   }
 }