Mips (Maps of Maps) • Language • docs.urbit.org

A mip is a map of maps. These can be constructed manually by nesting ordinary maps, but the %landscape desk contains a /lib/mip.hoon library which makes these a bit easier to deal with. You can copy the library into your own project. The various mip functions are documented below.

`++mip`

Mip (map of maps) mold builder

A mip is a map of maps. An outer map maps keys to inner maps, which themselves map keys to values.

A (mip kex key value) is equivalent to (map kex (map key value)).

Accepts

kex is a mold, the type of the outer map's key.

key is a mold, the type of the key of the inner maps.

value is a mold, the type of the value of the inner maps.

Produces

A mold.

Source

|%
++  mip                                                 ::  map of maps
  |$  [kex key value]
  (map kex (map key value))

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> *(mip:libmip @ @ @)
{}

> (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3) 
[n=[p=1 q=[n=[p=2 q=3] l=~ r=~]] l=~ r=~]

`++bi`

Mip engine

This is the container door for all the mip functions.

Accepts

a is a mip.

Source

++  bi                                                  ::  mip engine
  =|  a=(map * (map))
  |@

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> ~(. bi:libmip *(mip:libmip @ @ @))
< 8.bql
  [ a=nlr([p=@ q=nlr([p=@ q=@])])
    <2.gtk 17.zfg 35.yza 14.oai 54.ecl 77.swa 232.sje 51.qbt 123.ppa 46.hgz 1.pnw %140>
  ]
>

`++del:bi`

Delete item in mip

This takes two keys as its argument, b and c, and deletes c in the inner map that matches key b in the outer map . If this results in an empty inner map, then b is also deleted from the outer map.

Accepts

a is a mip, and is the +bi door's sample.

b is a key matching the key type of the outer map.

c is a key matching the key type of the inner maps.

Produces

A mip with c deleted from b, or b deleted from a if c ended up empty.

Source

++  del
  |*  [b=* c=*]
  =+  d=(~(gut by a) b ~)
  =+  e=(~(del by d) c)
  ?~  e
    (~(del by a) b)
  (~(put by a) b e)

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)
> =mymip (~(put bi:libmip mymip) 1 3 4)

> mymip
[n=[p=1 q=[n=[p=2 q=3] l=~ r=[n=[p=3 q=4] l=~ r=~]]] l=~ r=~]

> =mymip (~(del bi:libmip mymip) 1 2)

> mymip
[n=[p=1 q=[n=[p=3 q=4] l=~ r=~]] l=~ r=~]

> =mymip (~(del bi:libmip mymip) 1 3)

> mymip
~

`++get:bi`

Maybe get value in mip

Get the value of c in the map with key b in mip a as a unit. If there's no c in b or b in a, the unit is null.

Accepts

a is a mip, and is the sample of the ++bi door.

b is a key matching the key type of the outer map.

c is a key matching the key type of the inner maps.

Produces

A (unit [type]), where [type] is the value type. The unit is null if there's no c in b or no b in a.

Source

++  get
  |*  [b=* c=*]
  =>  .(b `_?>(?=(^ a) p.n.a)`b, c `_?>(?=(^ a) ?>(?=(^ q.n.a) p.n.q.n.a))`c)
  ^-  (unit _?>(?=(^ a) ?>(?=(^ q.n.a) q.n.q.n.a)))
  (~(get by (~(gut by a) b ~)) c)

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)

> (~(get bi:libmip mymip) 1 2)
[~ 3]

> (~(get bi:libmip mymip) 2 3)
~

`++got:bi`

Get value in mip or crash

Get the value of c in the map with key b in mip a. If there's no c in b or b in a, crash.

Accepts

a is a mip, and is the sample of the ++bi door.

b is a key matching the key type of the outer map.

c is a key matching the key type of the inner maps.

Produces

A noun of the type of the values in the mip, or else crashes.

Source

++  got
  |*  [b=* c=*]
  (need (get b c))

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)

> (~(got bi:libmip mymip) 1 2)
3

> (~(got bi:libmip mymip) 2 3)
/lib/mip/hoon:<[25 5].[25 21]>
dojo: hoon expression failed

`++gut:bi`

Get value in mip or default

Get the value of c in the map with key b in mip a. If there's no c in b or b in a, produce default value d.

Accepts

a is a mip, and is the sample of the ++bi door.

b is a key matching the key type of the outer map.

c is a key matching the key type of the inner maps.

d is a default value, which is produced if the value cannot be found.

Produces

A noun, either the type of the value in the map or d.

Source

++  gut
  |*  [b=* c=* d=*]
  (~(gut by (~(gut by a) b ~)) c d)

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)

> (~(gut bi:libmip mymip) 1 2 42)
3

> (~(gut bi:libmip mymip) 2 3 42)
42

`++has:bi`

Check if mip contains

Check if mip a contains c in b.

Accepts

a is a mip, and is the sample of the ++bi door.

b is a key matching the key type of the outer map.

c is a key matching the key type of the inner maps.

Produces

A ? which is true if c in b exists, and false otherwise.

Source

++  has
  |*  [b=* c=*]
  !=(~ (get b c))

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)

> (~(has bi:libmip mymip) 1 2)
%.y

> (~(has bi:libmip mymip) 2 3)
%.n

`++key:bi`

Get keys of inner map in mip

Get the set of keys of the inner map matching key b in the outer map. If b doesn't exist, an empty set is returned.

Accepts

a is a mip, and is the sample of the ++bi door.

b is a key matching the key type of the outer map.

Produces

A (set [type]) where [type] is the type of the keys in the inner map.

Source

++  key
  |*  b=*
  ~(key by (~(gut by a) b ~))

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)

> (~(key bi:libmip mymip) 1)
{2}

> (~(key bi:libmip mymip) 2)
{}

`++put:bi`

Insert value in mip

Add value d with key c to the inner map with key b in the outer map. If b doesn't exist, an inner map is also added with that key. If c already exists, its value is replaced with d.

Accepts

a is a mip, and is the sample of the ++bi door.

b is a key matching the key type of the outer map.

c is a key matching the key type of the inner maps.

d is a noun matching the type of the values in the mip.

Produces

A new, modified mip.

Source

++  put
  |*  [b=* c=* d=*]
  %+  ~(put by a)  b
  %.  [c d]
  %~  put  by
  (~(gut by a) b ~)

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)
> =mymip (~(put bi:libmip mymip) 1 1 42)
> =mymip (~(put bi:libmip mymip) 2 12 99)

> ~(tap bi:libmip mymip)
~[[x=2 y=12 v=99] [x=1 y=2 v=3] [x=1 y=1 v=42]]

`++tap:bi`

Convert mip to list

The mip is flattened to a list of the triple [x y v], where x is a key in the outer map, y is a key in an inner map, and v is its value.

Accepts

a is a mip, and is the sample of the ++bi door.

Produces

A triple cell of [x y v], where:

x is a key in the outer map.
y is a key in an inner map.
v is its value.

Source

++  tap
  ::NOTE  naive turn-based implementation find-errors ):
  =<  $
  =+  b=`_?>(?=(^ a) *(list [x=_p.n.a _?>(?=(^ q.n.a) [y=p v=q]:n.q.n.a)]))`~
  |.  ^+  b
  ?~  a
    b
  $(a r.a, b (welp (turn ~(tap by q.n.a) (lead p.n.a)) $(a l.a)))
--

Examples

> =libmip -build-file /=landscape=/lib/mip/hoon

> =mymip (~(put bi:libmip *(mip:libmip @ @ @)) 1 2 3)
> =mymip (~(put bi:libmip mymip) 1 1 42)
> =mymip (~(put bi:libmip mymip) 2 12 99)

> ~(tap bi:libmip mymip)
~[[x=2 y=12 v=99] [x=1 y=2 v=3] [x=1 y=1 v=42]]