where(whereClause) {
    return _.filter(this.realChoices, whereClause);
  }
EUC charset recognizers.  One abstract class that provides the common function
 for getting the next character according to the EUC encoding scheme,
 and nested derived classes for EUC_KR, EUC_JP, EUC_CN.

 Get the next character value for EUC based encodings.
 Character 'value' is simply the raw bytes that make up the character
    packed into an int.