2 lines per 1 binding (1 OT commandline entry) :)

AddFormat("msg sendfrom", {pFrom, pTo}, {pMsg, pSubj}, { {"--dryrun",pBool} , {"--cc",pNym} , {"--bcc",pNym} , {"--prio",pInt} },
  LAMBDA { auto &D=*d; return U.MsgSend(D.V(1), D.V(2) + D.o("--cc") , D.v(3), D.v(4,"nosubject"), stoi(D.o1("--prio","0")), D.has("--dryrun")); } );
Multiline support
Biding format modifications