Tokenizer.PutBack C# (CSharp) Method

    private void PutBack(char ch) 
    {
      if (_read.Length == 0) 
      {
        _read = new String(ch, 1);
      } 
      else 
      {
        _read = ch + _read;
      }
    }

 protected internal void PutBack(TSymbol symbol)
 {
     if (symbol != null)
     {
         Tokenizer.PutBack(symbol);
     }
 }