stock str_replace(_string[], _substr[], _substr_rp[])
{
    new _len = strlen(_substr), _len2 = strlen(_string), lastreplace;
    for(new x = strfind(_string, _substr); (x!= -1  || x > lastreplace) ; x = strfind(_string, _substr))
    {
        strdel(_string, x, x+_len);
        strins(_string, _substr_rp, x);
        lastreplace = x;
    }
    return 1;
}