case IP_AP_NOTCOMPAT : ret = tr("IP and AP not compatible"); break;
case IP_END_NULLCOL : ret = tr("IP ends with anull column (normally not possible during compat. check)"); break;
case AP_TOO_SHORT : ret = tr("AP has been badly computed, leading to a AP shorter than needed (NB: it is an abnormal case)"); break;
case IP_AP_NOTCOMPAT : ret = tr("IP and AP not compatible"); break;
case IP_END_NULLCOL : ret = tr("IP ends with anull column (normally not possible during compat. check)"); break;
case AP_TOO_SHORT : ret = tr("AP has been badly computed, leading to a AP shorter than needed (NB: it is an abnormal case)"); break;