%receipt
Below is an example of an application that spins up a lick port on its init call. When it recieves a %connected soak it subscribes to %rumors. whenever a %rumor is recieved it will spit it out to the Lick port and which will forward it to a reciept printer. When the receipt printer disconnects the application will unsubscribe to %rumors and wait.
receipt.hoon
/+ default-agent, dbug!:|%+$ versioned-state$% state-0==+$ state-0$: [%0 name=@tas]==+$ card card:agent:gall--%- agent:dbug=| state-0=* state -^- agent:gall|_ =bowl:gall+* this .default ~(. (default-agent this %|) bowl)++ on-init^- (quip card _this):_ this[%pass / %arvo %l %spin /rumors/uart]~++ on-save !>(state)++ on-load|= old=vase^- (quip card _this)`this(state !<(state-0 old))++ on-poke|= [=mark =vase]^- (quip card _this)?> ?=(%uart-action mark)=/ act !<(action vase)?- -.act%spin:_ this[%pass / %arvo %l %spin name.act]~::%shut:_ this[%pass /shut %arvo %l %shut name.act]~::%spit:_ this[%pass /spit %arvo %l %spit name.act mark.act data.act]~==::++ on-peek|= =path^- (unit (unit cage))~& >> path=/ dev `@tas`(snag 2 path)?+ path (on-peek:default path)[%s %agents *] ``noun+!>(dev)==++ on-arvo|= [=wire =sign-arvo]^- (quip card _this)=/ cad +.sign-arvo~& > ['wire' wire]~& > ['sign-arvo' sign-arvo]?+ sign-arvo (on-arvo:default wire sign-arvo)[%lick %soak *]?+ mark.sign-arvo [~ this]::%connect:_ this:~ [%pass /subscribe %agent [our.bowl %rumors] %watch /rumors]==::%disconnect:_ this:~ [%pass /subscribe %agent [our.bowl %rumors] %leave ~]==::%error~& > ['Error: ' ;;(@tas noun.sign-arvo)]`this====++ on-watch on-watch:default++ on-leave on-leave:default++ on-agent|= [=wire =sign:agent:gall]^- (quip card _this)?+ wire (on-agent:default wire sign)[%subscribe ~]?+ -.sign (on-agent:default wire sign)%watch-ack?~ p.sign((slog '%rumors-watcher: Subscribe succeeded!' ~) `this)((slog '%rumors-watcher: Subscribe failed!' ~) `this)::%kick%- (slog '%rumors-watcher: Got kick, resubscribing...' ~):_ this:~ [%pass /subscribe %agent [our.bowl %rumors] %watch /rumors]==::%fact?+ p.cage.sign (on-agent:default wire sign)%rumor=/ rumor !<([when=@da what=@t] q.cage.sign)=/ print :(weld (scow %da when.rumor) ": " (trip what.rumor))~& (crip print):_ this[%pass /spit %arvo %l %spit /rumors/uart %print (crip print)]~======::++ on-fail on-fail:default--