Ironically, heading over to Appendix B.2 of RFC 3525, and implementing the bulk of it superficially¹ it turns out your sample snippet is invalid.
It was missing ammParameter, that's not optional as soon as you have the opening {:
So, fixing the snippet, here's something to get you started. It's only 850 lines of code because the spec is lengthy:
Live On Coliru
//#define BOOST_SPIRIT_DEBUG #include <boost/spirit/include/qi.hpp> namespace qi = boost::spirit::qi; template <typename It> struct Megaco { struct Tokens { Tokens() { using namespace qi; auto SafeChar = copy(alnum | char_("-+&!_/'?@^`~*$\\()%|.")); auto RestChar = copy(char_(";[]{}:,#<>=")); auto WSP = copy(char_(" \t")); COMMENT = ';' >> *(SafeChar | RestChar | WSP | '"') >> (eol|eoi); SEP = +(WSP | COMMENT | eol); LWSP = *(WSP | COMMENT | eol); NAME = raw [ alpha >> repeat(0,63) [alnum|'_'] ]; // Note - The double-quote character is not allowed in quotedString. quotedString = '"' >> *(SafeChar | RestChar | WSP) >> '"'; VALUE = quotedString | lexeme[+SafeChar]; octetString = *("\\}" | char_("\x01-\x7C\x7E-\xFF")); MTPToken=no_case["MTP"]; H221Token=no_case["H221"]; H223Token=no_case["H223"]; H226Token=no_case["H226"]; V18Token=no_case["V18"]; V22Token=no_case["V22"]; V22bisToken=no_case["V22b"]; V32Token=no_case["V32"]; V32bisToken=no_case["V32b"]; V34Token=no_case["V34"]; V76Token=no_case["V76"]; V90Token=no_case["V90"]; V91Token=no_case["V91"]; BOOST_SPIRIT_DEBUG_NODES( // snipped for Stack Overflow, see Coliru ) } protected: using Token = qi::rule<It>; Token COMMENT, SEP, LWSP; qi::rule<It, std::string()> NAME, quotedString, VALUE, octetString; #define TOK(name,long,short) name##Token{qi::no_case[qi::lit(#long)|#short]}, Token TOK(Add,Add,A) TOK(Audit,Audit,AT) TOK(AuditCap,AuditCapability,AC) TOK(AuditValue,AuditValue,AV) TOK(Auth,Authentication,AU) TOK(Bothway,Bothway,BW) TOK(Brief,Brief,BR) TOK(Buffer,Buffer,BF) TOK(Ctx,Context,C) TOK(ContextAudit,ContextAudit,CA) TOK(DigitMap,DigitMap,DM) TOK(Disconnected,Disconnected,DC) TOK(Delay,Delay,DL) TOK(Duration,Duration,DR) TOK(Embed,Embed,EM) TOK(Emergency,Emergency,EG) TOK(Error,Error,ER) TOK(EventBuffer,EventBuffer,EB) TOK(Events,Events,E) TOK(Failover,Failover,FL) TOK(Forced,Forced,FO) TOK(Graceful,Graceful,GR) TOK(HandOff,HandOff,HO) TOK(ImmAckRequired,ImmAckRequired,IA) TOK(Inactive,Inactive,IN) TOK(Isolate,Isolate,IS) TOK(InSvc,InService,IV) TOK(InterruptByEvent,IntByEvent,IBE) TOK(InterruptByNewSignalsDescr,IntBySigDescr,IBS) TOK(KeepActive,KeepActive,KA) TOK(Local,Local,L) TOK(LocalControl,LocalControl,O) TOK(LockStep,LockStep,SP) TOK(Loopback,Loopback,LB) TOK(Media,Media,M) TOK(Megacop,MEGACO,!) TOK(Method,Method,MT) TOK(MgcId,MgcIdToTry,MG) TOK(Mode,Mode,MO) TOK(Modify,Modify,MF) TOK(Modem,Modem,MD) TOK(Move,Move,MV) TOK(Mux,Mux,MX) TOK(Notify,Notify,N) TOK(NotifyCompletion,NotifyCompletion,NC) TOK(ObservedEvents,ObservedEvents,OE) TOK(Oneway,Oneway,OW) TOK(OnOff,OnOff,OO) TOK(OtherReason,OtherReason,OR) TOK(OutOfSvc,OutOfService,OS) TOK(Packages,Packages,PG) TOK(Pending,Pending,PN) TOK(Priority,Priority,PR) TOK(Profile,Profile,PF) TOK(Reason,Reason,RE) TOK(Recvonly,ReceiveOnly,RC) TOK(Reply,Reply,P) TOK(Restart,Restart,RS) TOK(Remote,Remote,R) TOK(ReservedGroup,ReservedGroup,RG) TOK(ReservedValue,ReservedValue,RV) TOK(Sendonly,SendOnly,SO) TOK(Sendrecv,SendReceive,SR) TOK(Services,Services,SV) TOK(ServiceStates,ServiceStates,SI) TOK(ServiceChange,ServiceChange,SC) TOK(ServiceChangeAddress,ServiceChangeAddress,AD) TOK(SignalList,SignalList,SL) TOK(Signals,Signals,SG) TOK(SignalType,SignalType,SY) TOK(Stats,Statistics,SA) TOK(Stream,Stream,ST) TOK(Subtract,Subtract,S) TOK(SynchISDN,SynchISDN,SN) TOK(TerminationState,TerminationState,TS) TOK(Test,Test,TE) TOK(TimeOut,TimeOut,TO) TOK(Topology,Topology,TP) TOK(Trans,Transaction,T) TOK(ResponseAck,TransactionResponseAck,K) TOK(Version,Version,V) MTPToken, H221Token, H223Token, H226Token, V18Token, V22Token, V22bisToken, V32Token, V32bisToken, V34Token, V76Token, V90Token, V91Token; // The values 0x0, 0xFFFFFFFE and 0xFFFFFFFF are reserved. struct SpecialContexts : qi::symbols<char, uint32_t> { enum { NULL_, CHOOSE = 0xFFFFFFFEl, ALL = 0xFFFFFFFFl }; SpecialContexts() { this->add ("$", CHOOSE) ("*", ALL) ("-", NULL_); } } SpecialContext; }; struct Parser : Tokens, qi::grammar<It> { using Tokens::LWSP; using Tokens::SEP; using Tokens::SpecialContext; using Tokens::NAME; using Tokens::VALUE; using Tokens::quotedString; using Tokens::octetString; Parser() : Parser::base_type(megacoMessage) { using namespace qi; auto LBRKT = copy(LWSP >> '{' >> LWSP); auto RBRKT = copy(LWSP >> '}' >> LWSP); auto EQUAL = copy(LWSP >> '=' >> LWSP); auto COMMA = copy(LWSP >> ',' >> LWSP); auto INEQUAL = copy(LWSP >> char_("><#") >> LWSP); auto LSBRKT = copy(LWSP >> '[' >> LWSP); auto RSBRKT = copy(LWSP >> ']' >> LWSP); auto LPAREN = copy(LWSP >> '(' >> LWSP); auto RPAREN = copy(LWSP >> ')' >> LWSP); auto PIPE = copy(LWSP >> '|' >> LWSP); megacoMessage = LWSP >> -(authenticationHeader >> SEP) >> message; authenticationHeader = Tokens::AuthToken >> EQUAL >> ("0x" >> repeat(8)[xdigit]) >> ':' >> ("0x" >> repeat(8)[xdigit]) >> ':' >> repeat(24,64)[xdigit] ; message = Tokens::MegacopToken >> '/' >> Version >> SEP >> mId >> SEP >> messageBody; mId = ((domainAddress | domainName) >> -(':' >> portNumber)) | mtpAddress | deviceName ; domainName = '<' >> alnum >> repeat(0,63)[char_("a-zA-Z0-9.-")] >> '>'; deviceName = pathNAME.alias(); pathNAME // TODO total lenght limit according to RFC comment = -lit('*') >> NAME >> *char_("/*a-zA-Z0-9_$") >> -('@' >> pathDomainName); pathDomainName = raw [(alnum|'*') >> repeat(0,63)[alnum|'-'|'*'|'.'] ]; ContextID = SpecialContext | UINT32; domainAddress = '[' >> (IPv4address | IPv6address) >> ']'; // RFC2373 contains the definition of IP6Addresses. IPv6address = hexpart >> - (':' >> IPv4address); IPv4address = V4hex >> '.' >> V4hex >> '.' >> V4hex >> '.' >> V4hex; V4hex = qi::uint_parser<uint8_t, 10, 1, 3>{}; // "0".."255" hexpart = raw [ "::" >> -hexseq | hexseq >> "::" >> -hexseq | hexseq ]; hexseq = raw[ uint_parser<uint16_t, 16, 1, 4>{} % ':' ]; portNumber = UINT16; // TODO constraint checking? // To octet align the mtpAddress the MSBs shall be encoded as 0s. // An octet shall be represented by 2 hex digits. mtpAddress = Tokens::MTPToken >> LBRKT >> uint_parser<uint32_t, 16, 4, 8>{} >> RBRKT ; messageBody = errorDescriptor | transactionList; transactionList = +( transactionRequest | transactionReply | transactionPending | transactionResponseAck ); //Use of response acks is dependent on underlying transport transactionPending = Tokens::PendingToken >> EQUAL >> transactionID >> LBRKT >> RBRKT; transactionResponseAck = Tokens::ResponseAckToken >> LBRKT >> (transactionAck % COMMA) >> RBRKT; transactionAck = transactionID | (transactionID >> "-" >> transactionID); transactionRequest = Tokens::TransToken >> EQUAL >> transactionID >> LBRKT >> (actionRequest % COMMA) >> RBRKT; actionRequest = Tokens::CtxToken >> EQUAL >> ContextID >> LBRKT >> (( contextRequest >> -(COMMA >> commandRequestList)) | commandRequestList) >> RBRKT; contextRequest = ((contextProperties >> -(COMMA >> contextAudit)) | contextAudit); contextProperties = contextProperty % COMMA; // at-most-once contextProperty = (topologyDescriptor | priority | Tokens::EmergencyToken); contextAudit = Tokens::ContextAuditToken >> LBRKT >> (contextAuditProperties % COMMA) >> RBRKT; // at-most-once contextAuditProperties = ( Tokens::TopologyToken | Tokens::EmergencyToken | Tokens::PriorityToken ); // "O-" indicates an optional command // "W-" indicates a wildcarded response to a command commandRequestList = -lit("O-") >> -lit("W-") >> commandRequest >> *(COMMA >> -lit("O-") >> -lit("W-") >> commandRequest); commandRequest = ( ammRequest | subtractRequest | auditRequest | notifyRequest | serviceChangeRequest); transactionReply = Tokens::ReplyToken >> EQUAL >> transactionID >> LBRKT >> -( Tokens::ImmAckRequiredToken >> COMMA) >> ( errorDescriptor | actionReplyList ) >> RBRKT; actionReplyList = actionReply % COMMA ; actionReply = Tokens::CtxToken >> EQUAL >> ContextID >> LBRKT >> ( ( errorDescriptor | commandReply ) | (commandReply >> COMMA >> errorDescriptor) ) >> RBRKT; commandReply = (( contextProperties >> -(COMMA >> commandReplyList) ) | commandReplyList ); commandReplyList = commandReplys % COMMA ; commandReplys = (serviceChangeReply | auditReply | ammsReply | notifyReply ); //Add Move and Modify have the same request parameters ammRequest = (Tokens::AddToken | Tokens::MoveToken | Tokens::ModifyToken ) >> EQUAL >> TerminationID >> -(LBRKT >> (ammParameter % COMMA) >> RBRKT); //at-most-once ammParameter = (mediaDescriptor | modemDescriptor | muxDescriptor | eventsDescriptor | signalsDescriptor | digitMapDescriptor | eventBufferDescriptor | auditDescriptor); ammsReply = (Tokens::AddToken | Tokens::MoveToken | Tokens::ModifyToken | Tokens::SubtractToken ) >> EQUAL >> TerminationID >> -( LBRKT >> terminationAudit >> RBRKT ); subtractRequest = Tokens::SubtractToken >> EQUAL >> TerminationID >> -( LBRKT >> auditDescriptor >> RBRKT); auditRequest = (Tokens::AuditValueToken | Tokens::AuditCapToken ) >> EQUAL >> TerminationID >> LBRKT >> auditDescriptor >> RBRKT; auditReply = (Tokens::AuditValueToken | Tokens::AuditCapToken ) >> ( contextTerminationAudit | auditOther); auditOther = EQUAL >> TerminationID >> -(LBRKT >> terminationAudit >> RBRKT); terminationAudit = auditReturnParameter % COMMA; contextTerminationAudit = EQUAL >> Tokens::CtxToken >> ( terminationIDList | LBRKT >> errorDescriptor >> RBRKT ); auditReturnParameter = (mediaDescriptor | modemDescriptor | muxDescriptor | eventsDescriptor | signalsDescriptor | digitMapDescriptor | observedEventsDescriptor | eventBufferDescriptor | statisticsDescriptor | packagesDescriptor | errorDescriptor | auditItem); auditDescriptor = Tokens::AuditToken >> LBRKT >> -( auditItem % COMMA ) >> RBRKT; notifyRequest = Tokens::NotifyToken >> EQUAL >> TerminationID >> LBRKT >> ( observedEventsDescriptor >> -( COMMA >> errorDescriptor ) ) >> RBRKT; notifyReply = Tokens::NotifyToken >> EQUAL >> TerminationID >> -( LBRKT >> errorDescriptor >> RBRKT ); serviceChangeRequest = Tokens::ServiceChangeToken >> EQUAL >> TerminationID >> LBRKT >> serviceChangeDescriptor >> RBRKT; serviceChangeReply = Tokens::ServiceChangeToken >> EQUAL >> TerminationID >> -(LBRKT >> (errorDescriptor | serviceChangeReplyDescriptor) >> RBRKT); errorDescriptor = Tokens::ErrorToken >> EQUAL >> ErrorCode >> LBRKT >> -quotedString >> RBRKT; ErrorCode = repeat(1,4)[digit]; // could be extended transactionID = UINT32; // OTHER STUFF, DESCRIPTORS terminationIDList = LBRKT >> (TerminationID % COMMA) >> RBRKT; TerminationID = "ROOT" | pathNAME | "$" | "*"; mediaDescriptor = Tokens::MediaToken >> LBRKT >> (mediaParm % COMMA) >> RBRKT; // at-most one terminationStateDescriptor // and either streamParm(s) or streamDescriptor(s) but not both mediaParm = (streamParm | streamDescriptor | terminationStateDescriptor); // at-most-once per item streamParm = (localDescriptor | remoteDescriptor | localControlDescriptor); streamDescriptor = Tokens::StreamToken >> EQUAL >> StreamID >> LBRKT >> streamParm >> *(COMMA >> streamParm) >> RBRKT; localControlDescriptor = Tokens::LocalControlToken >> LBRKT >> localParm >> *(COMMA >> localParm) >> RBRKT; // at-most-once per item except for propertyParm localParm = (streamMode | propertyParm | reservedValueMode | reservedGroupMode); reservedValueMode = Tokens::ReservedValueToken >> EQUAL >> ( lit("ON") | "OFF" ); reservedGroupMode = Tokens::ReservedGroupToken >> EQUAL >> ( lit("ON") | "OFF" ); streamMode = Tokens::ModeToken >> EQUAL >> streamModes; streamModes = (Tokens::SendonlyToken | Tokens::RecvonlyToken | Tokens::SendrecvToken | Tokens::InactiveToken | Tokens::LoopbackToken ); propertyParm = pkgdName >> parmValue; parmValue = (EQUAL >> alternativeValue | INEQUAL >> VALUE); alternativeValue = ( VALUE | LSBRKT >> (VALUE % COMMA) >> RSBRKT // sublist (i.e., A AND B AND ...) | LBRKT >> (VALUE % COMMA) >> RBRKT // alternatives (i.e., A OR B OR ...) | LSBRKT >> VALUE >> ':' >> VALUE >> RSBRKT ) // range ; // Note - The octet zero is not among the permitted characters in // octet string. As the current definition is limited to SDP, and a // zero octet would not be a legal character in SDP, this is not a // concern. localDescriptor = Tokens::LocalToken >> LBRKT >> octetString >> RBRKT; remoteDescriptor = Tokens::RemoteToken >> LBRKT >> octetString >> RBRKT; eventBufferDescriptor= Tokens::EventBufferToken >> -( LBRKT >> eventSpec >> *( COMMA >> eventSpec) >> RBRKT ); eventSpec = pkgdName >> -( LBRKT >> (eventSpecParameter % COMMA) >> RBRKT ); eventSpecParameter = (eventStream | eventOther); eventBufferControl = Tokens::BufferToken >> EQUAL >> ( "OFF" | Tokens::LockStepToken ); terminationStateDescriptor = Tokens::TerminationStateToken >> LBRKT >> terminationStateParm >> *( COMMA >> terminationStateParm ) >> RBRKT; // at-most-once per item except for propertyParm terminationStateParm = (propertyParm | serviceStates | eventBufferControl); serviceStates = Tokens::ServiceStatesToken >> EQUAL >> ( Tokens::TestToken | Tokens::OutOfSvcToken | Tokens::InSvcToken ); muxDescriptor = Tokens::MuxToken >> EQUAL >> MuxType >> terminationIDList; MuxType = ( Tokens::H221Token | Tokens::H223Token | Tokens::H226Token | Tokens::V76Token | extensionParameter ); StreamID = UINT16; pkgdName = (PackageName >> '/' >> ItemID) //specific item | (PackageName >> "/*") //all items in package | "*/*" // all items supported by the MG ; PackageName = NAME.alias(); ItemID = NAME.alias(); eventsDescriptor = Tokens::EventsToken >> -( EQUAL >> RequestID >> LBRKT >> requestedEvent >> *( COMMA >> requestedEvent ) >> RBRKT ); requestedEvent = pkgdName >> -( LBRKT >> eventParameter >> *( COMMA >> eventParameter ) >> RBRKT ); // at-most-once each of KeepActiveToken , eventDM and eventStream //at most one of either embedWithSig or embedNoSig but not both //KeepActiveToken and embedWithSig must not both be present eventParameter = ( embedWithSig | embedNoSig | Tokens::KeepActiveToken | eventDM | eventStream | eventOther ); embedWithSig = Tokens::EmbedToken >> LBRKT >> signalsDescriptor >> -(COMMA >> embedFirst ) >> RBRKT; embedNoSig = Tokens::EmbedToken >> LBRKT >> embedFirst >> RBRKT; // at-most-once of each embedFirst = Tokens::EventsToken >> -( EQUAL >> RequestID >> LBRKT >> (secondRequestedEvent % COMMA) >> RBRKT ); secondRequestedEvent = pkgdName >> -( LBRKT >> secondEventParameter >> *( COMMA >> secondEventParameter ) >> RBRKT ); // at-most-once each of embedSig , KeepActiveToken, eventDM or // eventStream // KeepActiveToken and embedSig must not both be present secondEventParameter = ( embedSig | Tokens::KeepActiveToken | eventDM | eventStream | eventOther ); embedSig = Tokens::EmbedToken >> LBRKT >> signalsDescriptor >> RBRKT; eventStream = Tokens::StreamToken >> EQUAL >> StreamID; eventOther = eventParameterName >> parmValue; eventParameterName = NAME.alias(); eventDM = Tokens::DigitMapToken >> EQUAL >> ( digitMapName | (LBRKT >> digitMapValue >> RBRKT )); signalsDescriptor = Tokens::SignalsToken >> LBRKT >> -( signalParm % COMMA) >> RBRKT; signalParm = signalList | signalRequest; signalRequest = signalName >> -( LBRKT >> (sigParameter % COMMA) >> RBRKT ); signalList = Tokens::SignalListToken >> EQUAL >> signalListId >> LBRKT >> (signalListParm % COMMA) >> RBRKT; signalListId = UINT16; //exactly once signalType, at most once duration and every signal //parameter signalListParm = signalRequest.alias(); signalName = pkgdName.alias(); //at-most-once sigStream, at-most-once sigSignalType, //at-most-once sigDuration, every signalParameterName at most once sigParameter = sigStream | sigSignalType | sigDuration | sigOther | notifyCompletion | Tokens::KeepActiveToken; sigStream = Tokens::StreamToken >> EQUAL >> StreamID; sigOther = sigParameterName >> parmValue; sigParameterName = NAME.alias(); sigSignalType = Tokens::SignalTypeToken >> EQUAL >> signalType; signalType = (Tokens::OnOffToken | Tokens::TimeOutToken | Tokens::BriefToken); sigDuration = Tokens::DurationToken >> EQUAL >> UINT16; notifyCompletion = Tokens::NotifyCompletionToken >> EQUAL >> (LBRKT >> (notificationReason % COMMA) >> RBRKT); notificationReason = ( Tokens::TimeOutToken | Tokens::InterruptByEventToken | Tokens::InterruptByNewSignalsDescrToken | Tokens::OtherReasonToken ); observedEventsDescriptor = Tokens::ObservedEventsToken >> EQUAL >> RequestID >> LBRKT >> (observedEvent % COMMA) >> RBRKT; //time per event, because it might be buffered observedEvent = -( TimeStamp >> LWSP >> ':') >> LWSP >> pkgdName >> -( LBRKT >> (observedEventParameter % COMMA) >> RBRKT ); //at-most-once eventStream, every eventParameterName at most once observedEventParameter = eventStream | eventOther; // For an AuditCapReply with all events, the RequestID should be ALL. RequestID = ( UINT32 | "*" ); modemDescriptor = Tokens::ModemToken >> (( EQUAL >> modemType) | (LSBRKT >> (modemType % COMMA) >> RSBRKT)) >> -( LBRKT >> (propertyParm % COMMA) >> RBRKT ); // at-most-once except for extensionParameter modemType = (Tokens::V32bisToken | Tokens::V22bisToken | Tokens::V18Token | Tokens::V22Token | Tokens::V32Token | Tokens::V34Token | Tokens::V90Token | Tokens::V91Token | Tokens::SynchISDNToken | extensionParameter); digitMapDescriptor = Tokens::DigitMapToken >> EQUAL >> ( ( LBRKT >> digitMapValue >> RBRKT ) | (digitMapName >> -( LBRKT >> digitMapValue >> RBRKT )) ); digitMapName = NAME.alias(); digitMapValue = -("T:" >> Timer >> COMMA) >> -("S:" >> Timer >> COMMA) >> -("L:" >> Timer >> COMMA) >> digitMap; Timer = repeat(1,2)[digit]; // Units are seconds for T, S, and L timers, and hundreds of // milliseconds for Z timer. Thus T, S, and L range from 1 to 99 // seconds and Z from 100 ms to 9.9 s digitMap = (digitString | LPAREN >> digitStringList >> RPAREN); digitStringList = digitString >> *( PIPE >> digitString ); digitString = +digitStringElement; digitStringElement = digitPosition >> -lit('.'); digitPosition = digitMapLetter | digitMapRange; digitMapRange = ("x" | (LSBRKT >> digitLetter >> RSBRKT)); digitLetter = *((digit >> "-" >> digit ) | digitMapLetter); digitMapLetter = char_("0-9" //Basic event symbols "a-kA-K" "LS" // Inter-event timers (long, short) "Z" //Long duration modifier ); //at-most-once, and DigitMapToken and PackagesToken are not allowed //in AuditCapabilities command auditItem = ( Tokens::MuxToken | Tokens::ModemToken | Tokens::MediaToken | Tokens::SignalsToken | Tokens::EventBufferToken | Tokens::DigitMapToken | Tokens::StatsToken | Tokens::EventsToken | Tokens::ObservedEventsToken | Tokens::PackagesToken ); serviceChangeDescriptor = Tokens::ServicesToken >> LBRKT >> serviceChangeParm >> *(COMMA >> serviceChangeParm) >> RBRKT; // each parameter at-most-once // at most one of either serviceChangeAddress or serviceChangeMgcId // but not both // serviceChangeMethod and serviceChangeReason are REQUIRED serviceChangeParm = (serviceChangeMethod | serviceChangeReason | serviceChangeDelay | serviceChangeAddress | serviceChangeProfile | extension | TimeStamp | serviceChangeMgcId | serviceChangeVersion ); serviceChangeReplyDescriptor = Tokens::ServicesToken >> LBRKT >> (servChgReplyParm % COMMA) >> RBRKT; // at-most-once. Version is REQUIRED on first ServiceChange response // at most one of either serviceChangeAddress or serviceChangeMgcId // but not both servChgReplyParm = (serviceChangeAddress | serviceChangeMgcId | serviceChangeProfile | serviceChangeVersion | TimeStamp); serviceChangeMethod = Tokens::MethodToken >> EQUAL >> (Tokens::FailoverToken | Tokens::ForcedToken | Tokens::GracefulToken | Tokens::RestartToken | Tokens::DisconnectedToken | Tokens::HandOffToken | extensionParameter); // A serviceChangeReason consists of a numeric reason code // and an optional text description. // A serviceChangeReason MUST be encoded using the quotedString // form of VALUE. // The quotedString SHALL contain a decimal reason code, // optionally followed by a single space character and a // textual description string. serviceChangeReason = Tokens::ReasonToken >> EQUAL >> VALUE; serviceChangeDelay = Tokens::DelayToken >> EQUAL >> UINT32; serviceChangeAddress = Tokens::ServiceChangeAddressToken >> EQUAL >> ( mId | portNumber ); serviceChangeMgcId = Tokens::MgcIdToken >> EQUAL >> mId; serviceChangeProfile = Tokens::ProfileToken >> EQUAL >> NAME >> '/' >> Version; serviceChangeVersion = Tokens::VersionToken >> EQUAL >> Version; extension = extensionParameter >> parmValue; packagesDescriptor = Tokens::PackagesToken >> LBRKT >> packagesItem >> *(COMMA >> packagesItem) >> RBRKT; packagesItem = NAME >> "-" >> UINT16; TimeStamp = Date >> "T" >> Time; // per ISO 8601:1988 // Date = yyyymmdd Date = repeat(8)[digit]; // Time = hhmmssss Time = repeat(8)[digit]; statisticsDescriptor = Tokens::StatsToken >> LBRKT >> statisticsParameter >> *(COMMA >> statisticsParameter ) >> RBRKT; //at-most-once per item statisticsParameter = pkgdName >> -(EQUAL >> VALUE); topologyDescriptor = Tokens::TopologyToken >> LBRKT >> topologyTriple >> *(COMMA >> topologyTriple) >> RBRKT; topologyTriple = terminationA >> COMMA >> terminationB >> COMMA >> topologyDirection; terminationA = TerminationID.alias(); terminationB = TerminationID.alias(); topologyDirection = Tokens::BothwayToken | Tokens::IsolateToken | Tokens::OnewayToken; priority = Tokens::PriorityToken >> EQUAL >> UINT16; extensionParameter = "X" >> char_("-+") >> repeat(1,6)[alnum]; BOOST_SPIRIT_DEBUG_NODES( // snipped for Stack Overflow, see Coliru ) } private: qi::rule<It> megacoMessage, message; qi::rule<It, uint32_t()> mtpAddress, ContextID; qi::rule<It, std::string()> mId, domainName, deviceName, pathNAME, domainAddress, pathDomainName, IPv4address, IPv6address, hexpart, hexseq; qi::rule<It, uint16_t()> portNumber; qi::rule<It, uint8_t()> V4hex; // implicit lexemes (no implicit whitespace allowed): qi::rule<It> authenticationHeader; qi::uint_parser<int, 10, 1, 2> Version; qi::uint_parser<uint32_t, 10, 1, 10> UINT32; qi::uint_parser<uint16_t, 10, 1, 5> UINT16; // message payload qi::rule<It> messageBody, transactionList, transactionPending, transactionResponseAck, transactionAck, transactionRequest, actionRequest, contextRequest, contextProperties, contextProperty, contextAudit, contextAuditProperties, commandRequestList, commandRequest, transactionReply, actionReplyList, actionReply, commandReply, commandReplyList, commandReplys, ammRequest, ammParameter, ammsReply, subtractRequest, auditRequest, auditReply, auditOther, terminationAudit, contextTerminationAudit, auditReturnParameter, auditDescriptor, notifyRequest, notifyReply, serviceChangeRequest, serviceChangeReply, errorDescriptor, ErrorCode, transactionID; // OTHER STUFF, DESCRIPTORS qi::rule<It> terminationIDList, TerminationID, mediaDescriptor, mediaParm, streamParm, streamDescriptor, localControlDescriptor, localParm, reservedValueMode, reservedGroupMode, streamMode, streamModes, propertyParm, parmValue, alternativeValue, localDescriptor, remoteDescriptor, eventBufferDescriptor, eventSpec, eventSpecParameter, eventBufferControl, terminationStateDescriptor, terminationStateParm, serviceStates, muxDescriptor, MuxType, StreamID, pkgdName, PackageName, ItemID, eventsDescriptor, requestedEvent, eventParameter, embedWithSig, embedNoSig, embedFirst, secondRequestedEvent, secondEventParameter, embedSig, eventStream, eventOther, eventParameterName, eventDM, signalsDescriptor, signalParm, signalRequest, signalList, signalListId, signalListParm, signalName, sigParameter, sigStream, sigOther, sigParameterName, sigSignalType, signalType, sigDuration, notifyCompletion, notificationReason, observedEventsDescriptor, observedEvent, observedEventParameter, RequestID, modemDescriptor, modemType, digitMapDescriptor, digitMapName, digitMapValue, Timer, digitMap, digitStringList, digitString, digitStringElement, digitPosition, digitMapRange, digitLetter, digitMapLetter, auditItem, serviceChangeDescriptor, serviceChangeParm, serviceChangeReplyDescriptor, servChgReplyParm, serviceChangeMethod, serviceChangeReason, serviceChangeDelay, serviceChangeAddress, serviceChangeMgcId, serviceChangeProfile, serviceChangeVersion, extension, packagesDescriptor, packagesItem, TimeStamp, Date, Time, statisticsDescriptor, statisticsParameter, topologyDescriptor, topologyTriple, terminationA, terminationB, topologyDirection, priority, extensionParameter; }; }; int main() { std::string const sample = R"( !/3 [15.232.33.21]:2134 T=173619123 { C=230234621 { PR=9, MF=ip/187/6/23045241 { MD=V90 }, MF=ip/187/6/23045242 { MD=V90 } } })"; using It = std::string::const_iterator; Megaco<It>::Parser parser; It f = sample.begin(), l = sample.end(); bool ok = qi::parse(f, l, parser); if (ok) std::cout << "Parse success\n"; else std::cout << "Parse failed\n"; if (f != l) std::cout << "Remaining unparsed input: '" << std::string(f,l) << "'\n"; }
Prints
Parse success
¹ i.e. mostly dumb transformation of the productions, specifically barely no attribute handling and very heavy (e.g. no symbols<> for the modemtypes etc.)
