Arvo

The arvo.hoon file primarily contains the basic event processing and routing machinery of Arvo, but it also defines a number of useful types and other functions. Some of these have been excluded as they're obscure types only used internally by Arvo, but the rest are documented below.

$arch

Node identity

This represents a node in Clay, which may be a file or a directory.

Source

+$  arch  (axil @uvI)

Examples

> *arch
[fil=~ dir={}]

> .^(arch %cy %/sys)
[ fil=~
    dir
  { [p=~.hoon q=~]
    [p=~.lull q=~]
    [p=~.kelvin q=~]
    [p=~.vane q=~]
    [p=~.arvo q=~]
    [p=~.zuse q=~]
  }
]

> .^(arch %cy %/sys/arvo/hoon)
[   fil
  [ ~
    0v1s.31due.jlkt7.btvob.bhil7.fusae.55huv.7pghe.2ql6f.l495n.pi6ah
  ]
  dir={}
]

---

+axal

Fundamental node, recursive

This mold builder creates a representation of a node in Clay like an $arch or +axil, but the directory map contains more +axals, so it contains the entire subtree rather than just one level.

Source

++  axal
  |$  [item]
  [fil=(unit item) dir=(map @ta $)]

Examples

> *(axal @uvI)
[fil=~ dir={}]

> =/  =path  /sys/vane
  |-
  =+  .^(=arch %cy (en-beam [our %base da+now] path))
  ^-  (axal @uvI)
  :-  fil.arch
  (~(urn by dir.arch) |=([name=@ta ~] ^$(path (snoc path name))))
[ fil=~
    dir
  { [p=~.iris q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0v15.r0nos.81rq5.8t24j.vfnll.8ej0n.knuej.maetm.vr9ja.s3opn.5gtpd] dir={}]]}]]
    [p=~.clay q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0v12.hdbo4.a9j11.amut0.76dvc.cd69g.djmv9.nl9gi.e8m2t.jjfjl.i6sj3] dir={}]]}]]
    [p=~.eyre q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0v1a.l7oim.58p0r.j3qc6.jqce6.r1frb.2jc7u.oqs4f.cf14o.aucva.7vv43] dir={}]]}]]
    [p=~.dill q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0vq.r959f.eiqhv.0ujnq.4eb0r.3qtjq.lcsqt.ef8bu.lul18.abngb.1dbgl] dir={}]]}]]
    [p=~.ames q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0vb.va2dn.8ue5p.5bqal.tn08n.ce2k9.g2c55.dd4tc.5tv9d.7kru2.vvsh1] dir={}]]}]]
    [p=~.gall q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0v13.ovi2q.3vcok.4pn5v.470rl.msg6p.oo5rn.neoai.allbh.8ora9.h26it] dir={}]]}]]
    [p=~.khan q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0v1j.dnfbn.l5cts.4us65.cct40.2urng.hchvv.s2nvs.8pmnp.p7l3l.tqqer] dir={}]]}]]
    [p=~.behn q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0vu.4qadi.sar0t.rbp15.5n8o9.o6ifv.f52bj.nhof9.cl2nr.3osck.8d4ie] dir={}]]}]]
    [p=~.jael q=[fil=~ dir={[p=~.hoon q=[fil=[~ 0v5.4gubl.1bpjb.rnbrq.mir68.c25tq.euqfm.vqvg7.esv65.gp2in.r03op] dir={}]]}]]
  }
]

---

+axil

Fundamental node

This is the mold builder used to create a representation of a node in Clay. It's used by $arch.

Source

++  axil
  |$  [item]
  [fil=(unit item) dir=(map @ta ~)]

Examples

> *(axil @uvI)
[fil=~ dir={}]

> .^((axil @uvI) %cy %/sys/vane)
[ fil=~
    dir
  { [p=~.iris q=~]
    [p=~.clay q=~]
    [p=~.eyre q=~]
    [p=~.dill q=~]
    [p=~.ames q=~]
    [p=~.gall q=~]
    [p=~.khan q=~]
    [p=~.behn q=~]
    [p=~.jael q=~]
  }
]

---

$beak

Global context

This is the unencoded global path prefix for a node in Clay. It's a triple of a $ship, $desk and $case. The $case is a revision reference.

Source

+$  beak  (trel ship desk case)

Examples

> *beak
[p=~zod q=%$ r=[%ud p=0]]

> `beak`[our %base da+now]
[p=~zod q=%base r=[%da p=~2022.11.8..10.16.14..757a]]

> `beak`[our %base ud+1]
[p=~zod q=%base r=[%ud p=1]]

> `beak`[our %base tas+'foo']
[p=~zod q=%base r=[%tas p=%foo]]

---

$beam

Global name

An unencoded global path to a node in Clay. The $beak denotes the $ship, $desk and $case (revision reference), and then .s is the path to the node therein.

Source

+$  beam  [beak s=path]

Examples

> *beam
[[p=~zod q=%$ r=[%ud p=0]] s=/]

> `beam`[[our %base ud+1] /foo/bar]
[[p=~zod q=%base r=[%ud p=1]] s=/foo/bar]

---

$bone

Opaque duct handle

This is used by Ames to identify a particular message flow over the network.

Source

+$  bone  @ud

Examples

> *bone
0

> .^([snd=(set bone) rcv=(set bone)] %ax /=//=/bones/~nes)
[snd={0} rcv={}]

---

$case

Global version

A reference to a particular revision in Clay. It may be one of:

• %da: a date.

• %tas: a label (these are seldom used).

• %ud: a revision number. The initial commit is 1, and then each subsequent commit increments it.

+$  case
  $%  [%da p=@da]
      [%tas p=@tas]
      [%ud p=@ud]
  ==

Examples

> *case
[%ud p=0]

> `case`ud+123
[%ud p=123]

> `case`tas+'foo'
[%tas p=%foo]

> `case`da+now
[%da p=~2022.11.8..10.57.44..0e31]

---

$cage

Marked vase

A pair of a $mark and a $vase (type-value pair). These are extensively used for passing data around between vanes and agents.

Source

+$  cage  (cask vase)

Example

> *cage
[p=%$ q=[#t/* q=0]]

> `cage`[%noun !>('foo')]
[p=%noun q=[#t/@t q=7.303.014]]

---

+cask

Marked data builder

Like a $cage except rather than a $vase, the tail is whatever type was given to the mold builder. These are most frequently used for sending data over the network, as vases can only be used locally.

Source

++  cask  |$  [a]  (pair mark a)

Examples

> *(cask)
[p=%$ q=0]

> *(cask @t)
[p=%$ q='']

> `(cask @t)`[%noun 'foobar']
[p=%noun q='foobar']

> `(cask)`[%noun 'foobar']
[p=%noun q=125.762.588.864.358]

---

$desk

Local workspace

The name of a desk in Clay.

Source

+$  desk  @tas

Examples

> *desk
%$

> `desk`%base
%base

---

$dock

Message target

A pair of a $ship and Gall agent name. This is most frequently used when composing cards to other agents in a Gall agent.

Source

+$  dock  (pair @p term)

Examples

> *dock
[p=~zod q=%$]

> `dock`[our %dojo]
[p=~zod q=%dojo]

---

$gang

Infinite set of peers

This is used internally by the Scry interfaces in Arvo and its vanes.

Source

+$  gang  (unit (set ship))

Examples

> *gang
~

> `gang`[~ (silt ~zod ~nec ~)]
[~ {~nec ~zod}]

---

$mark

Symbolic content type

The name of a mark file. It will typically correspond to a file in the /mar directory of a desk.

Source

+$  mark  @tas

Examples

> *mark
%$

> `mark`%json
%json

---

$mien

Orientation

Some basic information given to Arvo: the local ship's name, the current time, and some entropy.

Source

+$  mien  [our=ship now=@da eny=@uvJ]

Examples

> *mien
[our=~zod now=~2000.1.1 eny=0v0]

---

$page

Untyped cage

A pair of a mark and a raw, untyped noun. This is primarily used in Clay.

Source

+$  page  (cask)

Examples

> *page
[p=%$ q=0]

> `page`[%noun [123 'abc']]
[p=%noun q=[123 6.513.249]]

---

+omen

Namespace path and data

Source

++  omen  |$  [a]  (pair path (cask a))

Examples

> *(omen @t)
[p=/ q=[p=%$ q='']]

---

$ship

Network identity

Another name for a @p.

Source

+$  ship  @p

Examples

> *ship
~zod

> `ship`~sampel
~sampel

---

$sink

Subscription

A triple of a $bone, $ship and $path.

Source

+$  sink  (trel bone ship path)

Examples

> *sink
[p=0 q=~zod r=/]

---

+hypo

Type-associated builder

A pair of a type and some value.

Source

++  hypo
  |$  [a]
  (pair type a)

Example

> *(hypo)
[#t/* q=0]

---

$meta

Meta-vase

Source

+$  meta  (pair)

Examples

> *meta
[p=0 q=0]

---

$maze

Vase, or meta-vase

Source

+$  maze  (each vase meta)

Examples

> *maze
[%.y p=[#t/* q=0]]

---

$ball

Dynamic kernel action

This contains the action or response in a kernel $move. One of:

• [%hurl [%error-tag stack-trace] wite=pass-or-gift]: action failed; error.

• [%pass wire=/vane-name/etc note=[vane=%vane-name task=[%.y p=vase]]]: advance; request.

• [%slip note=[vane=%vane-name task=[%.y p=vase]]]: lateral; make a request as though you're a different vane.

• [%give gift=[%.y vase]: retreat; response.

Source

+$  ball  (wite [vane=term task=maze] maze)

Examples

> *ball
[%give gift=[%.y p=[#t/* q=0]]]

---

$card

Tagged, untyped event

Note this is not the same as a card:agent:gall used in Gall agents.

Source

+$  card  (cask)

Examples

> *card
[p=%$ q=0]

---

$duct

Causal history

Arvo is designed to avoid the usual state of complex event networks: event spaghetti. We keep track of every event's cause so that we have a clear causal chain for every computation. At the bottom of every chain is a Unix I/O event, such as a network request, terminal input, file sync, or timer event. We push every step in the path the request takes onto the chain until we get to the terminal cause of the computation. Then we use this causal stack to route results back to the caller.

The Arvo causal stack is called a $duct. This is represented simply as a list of $wires (paths), where each path represents a step in the causal chain. The first element in the path is the vane handled that step in the computation, or an empty string for Unix.

Source

+$  duct  (list wire)

Examples

> `duct`-:~(tap in .^((set duct) %cx /=//=/tyre))
~[/gall/use/docket/0w3.kF2UY/~zod/tire /dill //term/1]

---

+hobo

%soft task builder

Source

++  hobo
  |$  [a]
  $?  $%  [%soft p=*]
      ==
      a
  ==

Examples

> *(hobo maze)
[%.y p=[#t/* q=0]]

---

$goof

Crash label and trace

Source

+$  goof  [mote=term =tang]

Examples

> *goof
[mote=%$ tang=~]

---

$mass

Memory usage

+whey produces a (list mass) for its memory report.

Source

+$  mass  $~  $+|+~
          (pair cord (each * (list mass)))

Examples

> *mass
[p='' q=[%.n p=~]]

---

$move

Cause and action

Arvo makes calls and produces results by processing $moves. The $duct is a call stack, and the $ball contains the action or response.

Source

+$  move  [=duct =ball]

Example

> *move
[duct=~ ball=[%give gift=[%.y p=[#t/* q=0]]]]

---

$ovum

card with cause

Source

+$  ovum  [=wire =card]

Examples

> *ovum
[wire=/ card=[p=%$ q=0]]

---

$roof

Namespace

Source

+$  roof  (room vase)                                   ::  namespace

---

$rook

Meta-namespace (super advanced)

Source

+$  rook  (room meta)                                   ::  meta-namespace

---

+room

Generic namespace

This is used internally for scry handlers.

Source

++  room                                                ::  either namespace
  |$  [a]
  $~  =>(~ |~(* ~))
  $-  $:  lyc=gang                                      ::  leakset
          vis=view                                      ::  perspective
          bem=beam                                      ::  path
      ==                                                ::
  %-  unit                                              ::  ~: unknown
  %-  unit                                              ::  ~ ~: invalid
  (cask a)

---

$roon

Partial namespace

Source

+$  roon                                                ::  partial namespace
  $~  =>(~ |~(* ~))
  $-  [lyc=gang car=term bem=beam]
  (unit (unit cage))

---

$root

Raw namespace

Source

+$  root  $-(^ (unit (unit)))

---

$view

Namespace perspective

Source

+$  view  $@(term [way=term car=term])

---

+wind

Kernel action builder

This is similar to +wite but without the error case. It's most commonly used in the type of a card:agent:gall.

Source

::
++  wind
  |$  ::  a: forward
      ::  b: reverse
      ::
      [a b]
  $%  ::  %pass: advance
      ::  %slip: lateral
      ::  %give: retreat
      ::
      [%pass p=path q=a]
      [%slip p=a]
      [%give p=b]
  ==

Examples

> *(wind note:agent:gall gift:agent:gall)
[%give p=[%poke-ack p=~]]

---

$wire

Event pretext

Type-wise, a $wire is the same as a $path; a +list of $knots with the syntax of /foo/bar/baz. While a $path is typically used in requests to denote a scry or subscription endpoint, a $wire is used for responses.

On the kernel-level, $wires are used in $ducts to represent a causal step in a call stack for routing purposes. In userspace, they're used the same way under the hood, but practically speaking, they can be thought of as "tags" for responses. That is, when you make a request to a vane of Gall agent, you provide a $wire for any responses you get back, and you can use this to identity what the response is for.

Source

+$  wire  path

Examples

> *wire
/

> `wire`/foo/bar/baz
/foo/bar/baz

---

+wite

Kernel action/error builder

This is used by the kernel in $moves. See the $ball entry for further details.

Source

++  wite
  |$  ::  note: a routed $task
      ::  gift: a reverse action
      ::
      ::    NB:  task: a forward action
      ::         sign: a sourced $gift
      ::
      [note gift]
  $%  ::  %hurl: action failed
      ::  %pass: advance
      ::  %slip: lateral
      ::  %give: retreat
      ::
      [%hurl =goof wite=$;($>(?(%pass %give) $))]
      [%pass =wire =note]
      [%slip =note]
      [%give =gift]
  ==

Examples

> *(wite [vane=term task=maze] maze)
[%give gift=[%.y p=[#t/* q=0]]]

---

+en-beam

Encode a $beam in a $path

Accepts

A $beam

Produces

A $path

Source

++  en-beam
  |=(b=beam =*(s scot `path`[(s %p p.b) q.b (s r.b) s.b]))

Examples

> (en-beam [~zod %base da+now] /foo/bar)
/~zod/base/~2023.1.9..10.35.30..f55a/foo/bar

---

+de-beam

Decode a $beam from a $path

Accepts

A $path

Produces

A $beam in a +unit, which is null if parsing failed.

Source

++  de-beam
  ~/  %de-beam
  |=  p=path
  ^-  (unit beam)
  ?.  ?=([@ @ @ *] p)  ~
  ?~  who=(slaw %p i.p)  ~
  ?~  des=?~(i.t.p (some %$) (slaw %tas i.t.p))  ~  :: XX +sym ;~(pose low (easy %$))
  ?~  ved=(de-case i.t.t.p)  ~
  `[[`ship`u.who `desk`u.des u.ved] t.t.t.p]

Examples

> (de-beam /~zod/base/~2023.1.9..10.35.30..f55a/foo/bar)
[~ [[p=~zod q=%base r=[%da p=~2023.1.9..10.35.30..f55a]] s=/foo/bar]]

---

+de-case

Parse a $case

Accepts

A $knot

Produces

A $case in a +unit, which is null if parsing failed.

Source

++  de-case
  ~/  %de-case
  |=  =knot
  ^-  (unit case)
  ?^  num=(slaw %ud knot)  `[%ud u.num]
  ?^  wen=(slaw %da knot)  `[%da u.wen]
  ?~  lab=(slaw %tas knot)  ~
  `[%tas u.lab]

Example

> (de-case '2')
[~ [%ud p=2]]

> (de-case '~2023.1.9..10.31.15..58ea')
[~ [%da p=~2023.1.9..10.31.15..58ea]]

> (de-case 'foo')
[~ [%tas p=%foo]]

> (de-case '!!!')
~

---