2q: Molds and Mold-Builders • Reference • developers.urbit.org

`+$axis`

Tree address

A Nock axis inside a noun. After the leading 1, in binary, a 1 signfies right and 0 left.

Source

+$  axis  @

Examples

> =axis `axis`7
> axis
7
> `@ub`axis
0b111

> =noun [[4 5] [6 14 15]]

> .*(noun [0 axis])
[14 15]

`+$bean`

Boolean

0, &, or %.y are true, and 1, |, and %.n are false.

Note 1 is false and 0 is true. This is sometimes referred to as "loobean".

Source

+$  bean  ?

Examples

> *bean
%.y

> `bean`&
%.y

> `bean`|
%.n

`+$flag`

Boolean

Same as $bean.

Source

+$  flag  ?

`+$char`

Character

A single @t character.

Source

+$  char  @t

Examples

> *char
''

> `char`'a'
'a'

`+$cord`

UTF-8 text

One of Hoon's two string types (the other being tape). A cord is an atom of UTF-8 text.

Source

+$  cord  @t

Examples

> *cord
''

> `@ux`'foobar'
0x7261.626f.6f66

> `@t`97
'a'

> `@`'urbit'
499.984.265.845

> `@t`499.984.265.845
'urbit'

Discussion

Aura @t designates a Unicode atom, little-endian: the first character in the text is the least-significant byte.

trip converts from cord to tape, and crip converts from tape to cord.

`+$byts`

bytes, LSB first

An atom dat with its byte-length specified in wid. This is to handle leading zeros that are typically ignored.

Source

+$  byts  [wid=@ud dat=@]

Examples

> *byts
[wid=0 dat=0]

> =a `byts`[4 2]
> a
[wid=4 dat=2]

> `@ux`(rev 3 a)
0x200.0000

`+$date`

Parsed date

A boolean designating AD or BC, a year atom, a month atom, and a tarp, which is a day atom and a time.

Source

+$  date  [[a=? y=@ud] m=@ud t=tarp]

Examples

> *date
[[a=%.y y=0] m=0 t=[d=0 h=0 m=0 s=0 f=~]]

> `date`(yore ~2014.6.6..21.09.15..0a16)
[[a=%.y y=2.014] m=6 t=[d=6 h=21 m=9 s=15 f=~[0xa16]]]

> now
~2018.5.25..17.55.15..9ad8

Discussion

`+$knot`

URL-safe path element text

An atom type that only permits lower-case letters, numbers, and four special characters: hyphen, tilde, underscore and period.

Source

+$  knot  @ta

Examples

> *knot
~.

> `@ta`105
~.i

`+$noun`

Any noun

Source

+$  noun  *

Examples

> *noun
0

> `noun`'foo'
7.303.014

> `noun`"foo"
[102 111 111 0]

`+$path`

Like unix path

A path is a list of $knot.

Source

+$  path  (list knot)

Examples

> *path
/

> `path`"foo"
/f/o/o

> `path`[~.foo ~.bar ~.baz ~]
/foo/bar/baz

`+$stud`

Standard name

Source

+$  stud                    ::  standard name
          $@  mark=@tas     ::  auth=urbit
          $:  auth=@tas     ::  standards authority
              type=path     ::  standard label
          ==                ::

`+$tang`

Bottom-first error

A list of tanks. It's for printing types and bottom-up printing of stack traces.

Source

+$  tang  (list tank)

Examples

> *tang
~

> %-  %-  slog
      ^-  tang
      :~  'foo'
          leaf+"bar"
          [%palm ["|" "(" "!" ")"] leaf+"foo" leaf+"bar" leaf+"baz" ~]
          [%rose [" " "[" "]"] leaf+"foo" leaf+"bar" leaf+"baz" ~]
      ==
foo
bar
(!foo|bar|baz)
[foo bar baz]
  ~
~

`+$tank`

Formatted print tree

A tank is one of four cases:

just a cord.
%leaf is just a tape.
%palm is a list of tank delimited by the strings in p, with back-steps at new lines.
%rose is a list of tank delimited by the strings in p without back-steps at new lines.

Source

+$  tank
  $~  leaf/~
  $@  cord
  $%  [%leaf p=tape]
      [%palm p=(qual tape tape tape tape) q=(list tank)]
      [%rose p=(trel tape tape tape) q=(list tank)]
  ==

Examples

> *tank
[%leaf p=""]

> ~(ram re 'foobar')
"foobar"

> ~(ram re leaf+"foo")
"foo"

> ~(ram re [%palm ["|" "(" "!" ")"] leaf+"foo" leaf+"bar" leaf+"baz" ~])
"(!foo|bar|baz)"

> ~(ram re [%rose [" " "[" "]"] leaf+"foo" leaf+"bar" leaf+"baz" ~])
"[foo bar baz]"

`+$tape`

List of characters

One of Hoon's two string types, the other being +cord. A tape is a list of @tD.

Source

+$  tape  (list @tD)

Examples

> *tape
""

> `tape`"foobar"
"foobar"

>`(list @t)`"foobar"
<|f o o b a r|>

>`(list @tD)`"foobar"
"foobar"

> `(list @)`"foobar"
~[102 111 111 98 97 114]

`+$tour`

UTF-32 clusters

A tour is a list of UTF-32 characters.

Source

+$  tour  (list @c)

Examples

> *tour
~

> `tour`(tuba "foobar")
~[~-f ~-o ~-o ~-b ~-a ~-r]

`+$tarp`

Parsed time

The time component of a date: day, hour, minute, second and a list of @ux for precision.

Source

+$  tarp  [d=@ud h=@ud m=@ud s=@ud f=(list @ux)]

Examples

> *tarp
[d=0 h=0 m=0 s=0 f=~]

> (yell now)
[d=106.751.991.821.625 h=22 m=58 s=10 f=~[0x44ff]]

> `tarp`(yell ~2014.6.6..21.09.15..0a16)
[d=106.751.991.820.172 h=21 m=9 s=15 f=~[0xa16]]

> (yell ~d20)
[d=20 h=0 m=0 s=0 f=~]

`+$term`

Hoon constant

A restricted text atom for Hoon constants. The only characters permitted are lowercase ASCII letters, -, and 0-9, the latter two of which cannot be the first character. The syntax for @tas is the text itself, always preceded by %. The empty @tas has a special syntax, $.

Source

+$  term  @tas

Examples

> *term
%$

> *%term
%term

> %dead-fish9
%dead-fish9

> -:!>(%dead-fish9)
#t/%dead-fish9

> -:!>(`@tas`%dead-fish9)
#t/@tas

`+$wain`

List of strings

A list of cords. A wain is used instead of a single cord with \n.

Source

+$  wain  (list cord)

Examples

> *wain
<||>

> `wain`/som/del/rok
<|som del rok|>

`+$wall`

List of list of characters

A list of tapes. wall is used instead of a single tape with \n.

Source

+$  wall  (list tape)

Examples

    > *wall
    <<>>

    > `wall`(wash [0 20] leaf+<(bex 256)>)
    <<
      "\\/115.792.089.237.\\/"
      "  316.195.423.570."
      "  985.008.687.907."
      "  853.269.984.665."
      "  640.564.039.457."
      "  584.007.913.129."
      "  639.936"
      "\\/                \\/"
    >>