Extending parser with proprietary sentences

[jtojnar]

I need to interact with a proprietary GPS logger that sends sentences like:

$PMTK182,8,0001F800,FFFFFFFFFFFFFF…FFFFF*52

Now I could wrap the parse_sentence function and handle those proprietary functions in the wrapper but I would have to duplicate code like checksum verification.

Possible solutions:

• Include the whole sentence as a struct field in ParseError::UnsupportedSentenceType so that wrapper can attempt to handle it after running parse_sentence.
• Return Ok(ParsedMessage::Proprietary(String)) from parse_sentence instead of ParseError::UnsupportedSentenceType.
• Factor out the verify_and_strip_checksum function and make it public.
• Add NmeaParserFull<ProprietaryMessagesType> (NmeaParser would become NmeaParserFull<()>) and a method like NmeaParserFull::register_parser_for_prefix<H>(prefix: &str, handler: H) where H: Fn(&str) -> Option<ProprietaryMessagesType>

[zaari]

I would be in favor of the first option (ParseError::UnsupportedSentenceType). Feel free to make a pull request.