Correctly match and print strings with escaped values

lib/src/pretty_print.dart

 // Copyright (c) 2013, 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 matcher.pretty_print;
 
 import 'description.dart';
 import 'interfaces.dart';
+import 'util.dart';
 
 /// Returns a pretty-printed representation of [object].
 ///
 /// If [maxLineLength] is passed, this will attempt to ensure that each line is
 /// no longer than [maxLineLength] characters long. This isn't guaranteed, since
 /// individual objects may have string representations that are too long, but
 /// most lines will be less than [maxLineLength] long.
 ///
 /// If [maxItems] is passed, [Iterable]s and [Map]s will only print their first
 /// [maxItems] members or key/value pairs, respectively.
@@ skipping 106 matching lines @@
   } catch (e) {
     return "?";
   }
 }
 
 /// Returns [source] with any control characters replaced by their escape
 /// sequences.
 ///
 /// This doesn't add quotes to the string, but it does escape single quote
 /// characters so that single quotes can be applied externally.
-String _escapeString(String source) =>
-    source.split("").map(_escapeChar).join("");
-
-/// Return the escaped form of a character [ch].
-String _escapeChar(String ch) {
-  switch (ch) {
-    case "'":
-      return "\\'";
-    case '\n':
-      return '\\n';
-    case '\r':
-      return '\\r';
-    case '\t':
-      return '\\t';
-    default:
-      return ch;
-  }
-}
+String _escapeString(String source) => escape(source).replaceAll("'", r"\'");