Parse the record by recombining the separated fields, then parsing the combined string. This is to be used with AsciiParser. 2010/03/11: Indeterminate field length is used when one field is in a record. 2010/03/11: The last field, if just one digit type (%S), can contain fractional part.
configure AsciiParser ap to use this field parser. The parser is registered with each column and the units are set.
suggest units for unpacking.
Either the field is accumulated in a string, and the entire string is parsed for the last field.