This document describes the data types for Gall defined in lull.hoon.

bitt

+$  bitt  (map duct (pair ship path))

Incoming subscriptions.

This is the structure Gall uses to keep track of subscribers to our Gall agent. The sup field of a bowl contains the bitt for our agent.

boat

+$  boat
  %+  map  [=wire =ship =term]
  [acked=? =path]

Outgoing subscriptions.

This is the structure Gall uses to keep track of subscriptions our agent has initiated. The wex field of a bowl contails the boat for that agent.

The wire field is the wire which sign:agents will come in on. The ship and term fields are the ship and the name of the agent to which our agent has subscribed.

The acked field is %.y if they have acknowledged our subscription request, and %.n if they have not. The path field is the path on the other agent to which our agent has subscribed.

bowl

+$  bowl                                              ::  standard app state
  $:  $:  our=ship                              ::  host
          src=ship                              ::  guest
          dap=term                              ::  agent
      ==                                        ::
      $:  wex=boat                              ::  outgoing subs
          sup=bitt                              ::  incoming subs
      ==                                        ::
      $:  act=@ud                               ::  change number
          eny=@uvJ                              ::  entropy
          now=@da                               ::  current time
          byk=beak                              ::  load source
  ==  ==                                        ::

Additional agent state.

A bowl is given to the agent core each time an event comes in. The fields are as follows:

• our: Our ship.
• src: The ship from which the current request originated.
• dap: The name of our agent.
• wex: Outgoing subscriptions. That is, subscriptions our agent has initiated. See the boat section for details of the type.
• sup: Incoming subscriptions. That is, subscriptions others have made to our agent. See the bitt section for details of the type.
• act: The total number of moves our agent has processed so far.
• eny: 512 bits of entropy.
• now: The current date-time.
• byk: The ship, desk and case in Clay from which this agent was loaded. The case will be [%da @da] where the @da is the when the agent was loaded. A beak is a triple of [ship desk case].

dude

+$  dude  term

Agent name.

gill

+$  gill  (pair ship term)

A general contact: A pair of the ship and agent name.

scar

+$  scar
  $:  p=@ud
      q=(map duct bone)
      r=(map bone duct)
  ==

Opaque duct - used internally.

suss

+$  suss  (trel dude @tas @da)

Configuration report.

well

+$  well  (pair desk term)

Desk and agent.

neat

+$  neat
  $%  [%arvo =note-arvo]
      [%agent [=ship name=term] =deal]
      [%pyre =tang]
  ==

Like a note:agent, except the %agent case has a deal instead of just a task:agent. This is used for messages that come in over the network and would not be used manually.

deal

+$  deal
  $%  [%raw-poke =mark =noun]
      task:agent
  ==

Like a task:agent but with the additional case of a raw poke. This is used for messages that come in over the network and would not be used manually.

unto

+$  unto
  $%  [%raw-fact =mark =noun]
      sign:agent
  ==

Like a sign:agent but with the additional case of a raw fact. This is used for messages that come in over the network and would not be used manually.

agent

++  agent
  =<  form
  |%

Container for Gall agent types. The most significant arm is form:agent, which specifies the structure of the agent itself. There are also some additional structures defined here, mostly defining the kinds of messages agents can send. The different arms of the core in agent are considered separately below.

step:agent

+$  step  (quip card form)

A cell of card:agents to be sent and a new agent state. This is the type returned by most arms of an agent. A (quip a b) is the same as [(list a) b], it's just a more convenient way to specify it.

card:agent

+$  card  (wind note gift)

An effect - typically a message to be sent to another agent or vane. A list of these are returned by most agent arms along with a new state in a step:agent. A wind is the following:

++  wind
  |$  [a b]
  $%  [%pass p=path q=a]
      [%slip p=a]
      [%give p=b]
  ==

Gall will not allow a %slip, so in practice a card will be one of:

• [%pass path note]
• [%give gift]

For %pass, p specifies the wire on which a response should be returned. See note:agent and gift:agent below for details of their types.

note:agent

+$  note
  $%  [%agent [=ship name=term] =task]
      [%arvo note-arvo]
      [%pyre =tang]
  ==

The type for messages initiated by our agent. This is opposed to gift:agent, which is the type for responding to other agents or vanes, or for sending out updates to subscribers. The three cases are:

• %agent: Poke another agent, subscribe to another agent, or cancel a subscription to another agent. The ship and name fields are the ship and agent to which the task should be sent. The task is the request itself, see task:agent below for its possible types.
• %arvo: Pass a task to a vane. The type of a note-arvo is:

  +$  note-arvo
    $~  [%b %wake ~]
    $%  [%a task:ames]
        [%b task:behn]
        [%c task:clay]
        [%d task:dill]
        [%e task:eyre]
        [%g task:gall]
        [%i task:iris]
        [%j task:jael]
        [%$ %whiz ~]
        [@tas %meta vase]
    ==

  You can refer to the /sys/lull.hoon source code for all the possible vane tasks, or see each vane's API Reference section in the Arvo documentation
• %pyre: This is for aborting side-effects initiated during agent installation. The tang is an error message.

A note:agent is always wrapped in a %pass card:agent.

task:agent

+$  task
  $%  [%watch =path]
      [%watch-as =mark =path]
      [%leave ~]
      [%poke =cage]
      [%poke-as =mark =cage]
  ==

The types of messages initiated by our agent and sent to another agent. This is in contrast to gift:agents, which are responses to incoming messages from agents or updates to agents already subscribed. The five kinds are:

• %watch: Subscribe to path on the target ship and agent.
• %watch-as: Same as %watch, except you ask the target's Gall to convert subscription updates to the mark you specified rather than just giving you the mark produced by the agent.
• %leave: Cancel subscription. The particular subscription to cancel will be determined by the wire given in the p field of the containing %pass card:agent.
• %poke: Poke the target ship and agent with the given cage, which is a pair of [mark vase].
• %poke-as: Same as %poke, except the cage will be converted to the specified mark before sending.

A task:agent is always wrapped in a %pass card:agent.

gift:agent

+$  gift
  $%  [%fact paths=(list path) =cage]
      [%kick paths=(list path) ship=(unit ship)]
      [%watch-ack p=(unit tang)]
      [%poke-ack p=(unit tang)]
  ==

The types of messages our agent can either send in response to messages from other agents, or send to subscribed agents. This is in contrast to task:agents, which are messages to other agents our agent initiates rather than sends in response. The four kinds are:

• %fact: An update to existing subscribers. The paths field specifies which subscription paths the update should go out to. The cage is the data, and is a [mark vase].
• %kick: Kick subscriber, ending their subscription. The paths field specifies which paths the subscriber should be kicked from, and the ship field specifies the ship to kick. If the ship field is null, all subscribers on the specified paths are kicked. Gall will automatically remove the subscription from our agent's bitt (inbound subscription map), and subscriber will no longer receive updates on the paths in question.
• %watch-ack: Acknowledge a subscription request. If p is null, it's an ack (positive acknowledgement), and if p is non-null, it's a nack (negative acknowledgement). Simply crashing will caused Gall to nack a subscription request, and not crashing but not explicitly producing a %watch-ack gift will cause Gall to ack a subscription request. Therefore, you'd typically only explicitly produce a %watch-ack gift if you wanted to nack a subscription request with a custom error in the tang.
• %poke-ack: Acknowledge a poke. If p is null, it's an ack, and if p is non-null, it's a nack. Simply crashing will cause Gall to nack a poke, and not crashing but not explicitly producing a %poke-ack gift will cause Gall to ack a poke. Therefore, you'd typically only explicitly produce a %poke-ack gift if you wanted to nack a poke with a custom error in the tang.

A gift:agent is always wrapped in a %give card:agent.

sign:agent

+$  sign
  $%  [%poke-ack p=(unit tang)]
      [%watch-ack p=(unit tang)]
      [%fact =cage]
      [%kick ~]
  ==

A sign is like a gift:agent but it's something that comes in to our agent from another agent rather than something we send out. The possible types are:

• %poke-ack: Another agent has acked (positively acknowledged) or nacked (negatively acknowledged) a %poke task:agent we previously sent. It's an ack if p is null and a nack if p is non-null. The tang contains an error or traceback if it's a nack.
• %watch-ack: Another agent has acked or nacked a %watch task:agent (subscription request) we previously sent. It's an ack if p is null and a nack if p is non-null. The tang contains an error or traceback if it's a nack. If it's a nack, Gall will automatically remove the subscription from our agent's boat (outbound subscription map).
• %fact: An update from another agent to which we've previously subscribed with a %watch task:agent (subscription request). The cage contains the data, and is a [mark vase].
• %kick: Our subscription to another agent has been ended, and we'll no longer receive updates. A %kick may be intentional, but it may also happen due to certain network conditions or other factors. As a result, it's best to try and resubscribe with another %watch task:agent, and if they nack the %watch, we can conclude it was intentional and give up.

form:agent

++  form
  $_  ^|
  |_  bowl
  ++  on-init
    *(quip card _^|(..on-init))
  ::
  ++  on-save
    *vase
  ::
  ++  on-load
    |~  old-state=vase
    *(quip card _^|(..on-init))
  ::
  ++  on-poke
    |~  [mark vase]
    *(quip card _^|(..on-init))
  ::
  ++  on-watch
    |~  path
    *(quip card _^|(..on-init))
  ::
  ++  on-leave
    |~  path
    *(quip card _^|(..on-init))
  ::
  ++  on-peek
    |~  path
    *(unit (unit cage))
  ::
  ++  on-agent
    |~  [wire sign]
    *(quip card _^|(..on-init))
  ::
  ++  on-arvo
    |~  [wire sign-arvo]
    *(quip card _^|(..on-init))
  ::
  ++  on-fail
    |~  [term tang]
    *(quip card _^|(..on-init))
  --
--

This defines the structure of the agent itself. The agent is a door with a bowl as its sample and exactly ten arms. Below we'll describe each arm briefly.

on-init

• Accepts: Nothing.
• Produces: step:agent

This arm is called when the agent is initially installed.

on-poke

• Accepts: cage
• Produces: step:agent

This arm is called when another agent pokes our agent.

on-watch

• Accepts: path
• Produces: step:agent

This arm is called when another agent subscribes to our agent.

on-leave

• Accepts: path
• Produces: step:agent

This arm is called when another agent unsubscribes from a subscription path on our agent.

on-peek

• Accepts: path
• Produces: (unit (unit cage))

This arm is called when a scry is performed on our agent.

on-agent

• Accepts: [wire sign:agent]
• Produces: step:agent

This arm is called when another agent give our agent a sign:agent.

on-arvo

• Accepts: [wire sign-arvo]
• Produces: step:agent

This arm is called when a vane gives our agent a gift. A sign-arvo is:

+$  sign-arvo
  $%  [%ames gift:ames]
      $:  %behn
          $%  gift:behn
              $>(%wris gift:clay)
              $>(%writ gift:clay)
              $>(%mere gift:clay)
              $>(%unto gift:gall)
          ==
      ==
      [%clay gift:clay]
      [%dill gift:dill]
      [%eyre gift:eyre]
      [%gall gift:gall]
      [%iris gift:iris]
      [%jael gift:jael]
  ==

You can refer to the /sys/lull.hoon source code, or the API Reference of each vane in the Arvo documentation.

on-fail

• Accepts: [term tang]
• Produces: step:agent

This arm is called if certain errors occur in Gall, such as if our agent tries to create a duplicate subscription.