function init(reporter, file, parser, traceurOptions) {
  // These are all module local variables. It is up to the  caller to ensure
  // that there is only one user of that scanner at the same time.
  errorReporter = reporter;
  lineNumberTable = file.lineNumberTable;
  input = file.contents;
  length = file.contents.length;
  setIndex(0);
  currentParser = parser;
  options = traceurOptions;
}
@param {ErrorReport} reporter
@param {SourceFile} file
@param {Parser} parser
@param {Options} traceurOptions