anchor.diff:    return input.padLeft(leftWidth + input.length, fill).padRight(width, fill);
   }
   
  -/**
  - * Returns `true` if [a] and [b] are equal after being converted to lower case,
  - * or are both null.
  - */
  +/// Returns `true` if [a] and [b] are equal after being converted to lower case,
  +/// or are both null.
   bool equalsIgnoreCase(String a, String b) => (a == null && b == null) ||
       (a != null && b != null && a.toLowerCase() == b.toLowerCase());
   
  -/**
  - * Compares [a] and [b] after converting to lower case.
  - *
  - * Both [a] and [b] must not be null.
  - */
  +/// Compares [a] and [b] after converting to lower case.
  +///
  +/// Both [a] and [b] must not be null.
   int compareIgnoreCase(String a, String b) =>
       a.toLowerCase().compareTo(b.toLowerCase());
  
positive.code:   }
  }
  
  /**
   * Returns `true` if [rune] represents a whitespace character.
   *
   * The definition of whitespace matches that used in [String.trim] which is
   * based on Unicode 6.2. This maybe be a different set of characters than the
   * environment's [RegExp] definition for whitespace, which is given by the
   * ECMAScript standard: http://ecma-international.org/ecma-262/5.1/#sec-15.10
   */
  bool isWhitespace(int rune) => ((rune >= 0x0009 && rune <= 0x000D) ||
      rune == 0x0020 ||
      rune == 0x0085 ||
  
negative.code:     rune == 0x3000 ||
      rune == 0xFEFF);
  
  /// Returns a [String] of length [width] padded with the same number of
  /// characters on the left and right from [fill].  On the right, characters are
  /// selected from [fill] starting at the end so that the last character in [fill]
  /// is the last character in the result. [fill] is repeated if neccessary to pad.
  ///
  /// Returns [input] if `input.length` is equal to or greater than width. [input]
  /// can be `null` and is treated as an empty string.
  ///
  /// If there are an odd number of characters to pad, then the right will be
  /// padded with one more than the left.
  String center(String input, int width, [String fill = ' ']) {
    if (fill?.length != 1) {
      throw new ArgumentError('fill must be exactly 1 character');
  