visitForRangeStmt method 
    
    
    
  Implementation
  @override
String visitForRangeStmt(ForRangeStmt forRangeStmt) {
  final output = StringBuffer();
  output.write('${_lexicon.kFor} ');
  if (forRangeStmt.hasBracket) {
    output.write(_lexicon.groupExprStart);
  }
  final declString = formatAST(forRangeStmt.iterator);
  final collectionString = formatAST(forRangeStmt.collection);
  output.write('$declString ${_lexicon.kIn} $collectionString');
  if (forRangeStmt.hasBracket) {
    output.write('${_lexicon.groupExprEnd} ');
  }
  final stmtString = formatAST(forRangeStmt.loop);
  output.write(stmtString);
  return output.toString();
}