Add new SpanScanner.eager().

lib/src/line_scanner.dart

 // Copyright (c) 2014, 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 string_scanner.line_scanner;
 
 import 'package:charcode/ascii.dart';
 
 import 'string_scanner.dart';
 
+// Note that much of this code is duplicated in eager_span_scanner.dart.
+
 /// A regular expression matching newlines across platforms.
 final _newlineRegExp = new RegExp(r"\r\n?|\n");
 
 /// A subclass of [StringScanner] that tracks line and column information.
 class LineScanner extends StringScanner {
   /// The scanner's current (zero-based) line number.
   int get line => _line;
   int _line = 0;
 
   /// The scanner's current (zero-based) column number.
@@ skipping 95 matching lines @@
   final int position;
 
   /// The zero-based line number of the scanner in this state.
   final int line;
 
   /// The zero-based column number of the scanner in this state.
   final int column;
 
   LineScannerState._(this._scanner, this.position, this.line, this.column);
 }