Surely the GPS driver library must assemble NMEA sentences from the stream, in order to extract the appropriate details; I was just thinking that if it (or this) made the 'last decoded' version of each message type (e.g. GGA, GSA or RMC) available, then if somebody wanted details not currently available, they could extract it from an already validated message, rather than duplicating that functionality..
I would like to get the 'Position fix indicator' value from the GGA message, so I can tell if DGPS is being used (i.e. the EGNOS satellite(s) are visible)..