function remove_path(name: filenames): filenames;
function path_only(name: filenames): filenames;
function name_only(name: filenames): filenames;
function remove_ext(name: filenames): filenames;
function ext_only(name: filenames): filenames;
procedure cons_path(var path: filenames;
                    dir,name: filenames);
procedure cons_name(var resu:          filenames;
                    name1,name2,ext:   filenames);