代码求注解！该怎么处理

代码求注解！
for j := 1 to Seriallength do  
  begin
  if Serialtype = 10 then
  begin
  CheckStr := UpperCase(Copy(barcode,j,1));
  if not (CheckStr[1] in ['0','1','2','3','4','5','6','7','8','9']) then
  Result := false
  else
  Result := true;
  end

[解决办法]
前面的循环判断就不说了
CheckStr := UpperCase(Copy(barcode,j,1));
这句是把barcode从j开始1个字符转大写赋给CheckStr

CheckStr[1] in是判断CheckStr第一个字符是否在['0','1','2','3','4','5','6','7','8','9']范围内