string posting_preprocessing(int posting_index)
{
    string posting = get_posting_text_from_data_base_by( posting_index );
    posting = tt_posting_preprocessing( posting );
    std::list<posting_preprocessing_module*> modules = tt_list_of_using_plugin_of posting_preprocessing();
    for(iterator iter=modules.begin(); iter != modules.end(); iter++) {
        posting_preprocessing_module* module = *iter;
        posting = module->preprocessing( posting );
    }
    return posting;
}

string tt_posting_preprocessing(string posting)
{
    // convert "[##_ ... _##]" to html
    return posting;
}

string sample_module( string posting )
{
    while( find(posting, "[ code cpp]") == true ) {
        from = find_pos(posting, "[code cpp]");
        to = find_pos_from(posting, "[/ code]
", from);
        string before = substring_from_to(posting, 0, from);
        string convertto = substring_from_to(posting, from, to);
        string after = substring_from_to(posting, to, posting.size());
        {
            convert_string_from_to( convertto, "if", "<font color=blue><b>if</b></font>"); // 걍 "if" 란 스트링을 "..." 으로 바꾼다고 칩시다.
            convert_string_from_to( convertto, "then", "<font color=blue><b>then</b></font>");
            convert_string_from_to( convertto, "else", "<font color=blue><b>else</b></font>");
            convert_string_from_to( convertto, "int", "<font color=blue><b>int</b></font>");
            convert_string_from_to( convertto, "double", "<font color=blue><b>double</b></font>");
            ...
        }
        posting = before + convertto + after;
    }
    return posting;
}