Reading values from text file of unknown structure

Thanks for all replies and hints. My question was, actually, whether Fortran itself does offer such a possibility. It seems, regrettably, it does not. Non-advancing input excludes list-directed format. Formatted STREAM input which, in principle, should provide such a functionality, for some reason does not either, working in a record-oriented way, contrary to the very idea of stream, what was already discussed here.