2k: Queue Logic

+to

Queue operations

Container arm for queue operation arms. The contained arms inherit a, its sample queue.

Accepts

a is a tree.

Source

++  to
  =|  a=(tree)  ::  (qeu)
  |@

Discussion

tree is the generic tree-shape mold. Maps, sets, and queues all share that shape, but they put their elements in different places and have different interfaces. to is the interface core for qeu; it's not generic across all the different containers that use tree.

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+apt:to

Check correctness

Test whether queue a is correctly ordered, producing a flag.

Accepts

a is a que.

Produces

A ?.

Source

++  apt
  |-  ^-  ?
  ?~  a  &
  ?&  ?~(l.a & ?&((mor n.a n.l.a) $(a l.a)))
      ?~(r.a & ?&((mor n.a n.r.a) $(a r.a)))
  ==

Examples

> =bad `(qeu @ud)`[1 ~ 2 ~ 3 ~ ~]

> ~(apt to bad)
%.n

> =good `(qeu @ud)`(~(gas to `(qeu @ud)`~) ~[1 2 3])

> ~(apt to good)
%.y

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++bal:to

Balance

Vertically rebalances queue a.

Accepts

a is a qeu.

Produces

A qeu.

Source

++  bal
  |-  ^+  a
  ?~  a  ~
  ?.  |(?=(~ l.a) (mor n.a n.l.a))
    $(a l.a(r $(a a(l r.l.a))))
  ?.  |(?=(~ r.a) (mor n.a n.r.a))
    $(a r.a(l $(a a(r l.r.a))))
  a

Examples

> =a `(qeu @ud)`[1 ~ 2 ~ 3 ~ ~]
> a
{1 2 3}
> `*`a
[1 0 2 0 3 0 0]
> ~(apt to a)
%.n

> =z `(qeu @ud)`~(bal to a)
> z
{1 2 3}
> `*`z
[2 [1 0 0] 3 0 0]
> ~(apt to z)
%.y

---

++dep:to

Maximum Depth

Produces the maximum depth of leaves (r.a and l.a) in queue a.

Accepts

a is a queue.

Produces

An atom.

Source

++  dep
  |-  ^-  @
  ?~  a  0
  +((max $(a l.a) $(a r.a)))

Examples

> =a (~(gas to `(qeu @)`~) `(list @)`[1 2 3 4 5 6 7 ~])
> ~(dep to a)
4

> =a (~(gas to `(qeu @)`~) `(list @)`[1 2 3 4 ~])
> ~(dep to a)
3

> =a (~(gas to `(qeu @)`~) `(list @)`[1 2 ~])
> ~(dep to a)
2

> ~(dep to `(qeu tape)`["a" ~ "b" ~ "c" ~ "d" ~ "e" ~ "f" ~ "g" ~ ~])
7

> ~(dep to ~(bal to `(qeu tape)`["a" ~ "b" ~ "c" ~ "d" ~ "e" ~ "f" ~ "g" ~ ~]))
4

---

++gas:to

Push list

Push all elements of list b into the queue a.

Accepts

a is a queue, and is the sample of +to.

b is a list.

Produces

A queue.

Source

++  gas
  |=  b=(list _?>(?=(^ a) n.a))
  |-  ^+  a
  ?~(b a $(b t.b, a (put i.b)))

Examples

> `(qeu)`(~(gas to `(qeu @)`~) [1 2 3 ~])
{3 2 1}

> =a (~(gas to `(qeu @)`~) [1 2 3 ~])
> =b [4 5 6 ~]
> `(qeu)`(~(gas to a) b)
{6 5 4 3 2 1}

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++get:to

Head-tail pair

Produces the head and tail queue of a.

Accepts

a is a queue.

Produces

A cell of the last element in a along with the rest of queue a.

Source

++  get
  |-  ^+  ?>(?=(^ a) [p=n.a q=*(tree _n.a)])
  ?~  a
    !!
  ?~  r.a
    [n.a l.a]
  =+  b=$(a r.a)
  :-  p.b
  ?:  |(?=(~ q.b) (mor n.a n.q.b))
    a(r q.b)
  a(n n.q.b, l a(r l.q.b), r r.q.b)

Examples

> =s (~(gas to *(tree @)) `(list @)`~[1 2 3])
> ~(get to s)
[p=1 q={3 2}]

> ~(get to ~)
dojo: hoon expression failed

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++nap:to

Remove head

Removes the head of queue a, producing the resulting queue.

Accepts

a is a queue.

Produces

A queue.

Source

++  nap
  ?>  ?=(^ a)
  ?:  =(~ l.a)  r.a
  =+  b=get(a l.a)
  bal(n.a p.b, l.a q.b)

Examples

> =a (~(gas to `(qeu @)`~) `(list @)`[1 2 3 4 5 6 ~])
> -.a
n=6

> =b ~(nap to a)
> -.b
n=2

> a
[n=6 l={} r={5 4 3 2 1}]

> b
[n=2 l=[n=4 l={5} r={3}] r=[n=1 l={} r={}]]

> `(qeu)`b
{5 4 3 2 1}

> `(qeu)`a
{6 5 4 3 2 1}

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++nip:to

Removes the root of queue a, producing the resulting queue.

Accepts

a is a queue.

Produces

A queue.

Source

++  nip
  |-  ^+  a
  ?~  a  ~
  ?~  l.a  r.a
  ?~  r.a  l.a
  ?:  (mor n.l.a n.r.a)
    l.a(r $(l.a r.l.a))
  r.a(l $(r.a l.r.a))

Examples

> =a (~(gas to `(qeu @)`~) `(list @)`[1 2 3 4 5 6 ~])
> a
[n=6 l={} r={5 4 3 2 1}]

> ~(nip to a)
[n=2 l=[n=4 l={5} r={3}] r=[n=1 l={} r={}]]

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++put:to

Insert

Accept noun b and adds to queue a as the head, producing the resulting queue.

Accepts

a is a queue, and is the sample of +to.

b is a noun.

Produces

A queue.

Source

++  put
  |*  b=*
  |-  ^+  a
  ?~  a
    [b ~ ~]
  bal(l.a $(a l.a))

Examples

> =a (~(gas to `(qeu @)`~) `(list @)`[3 1 2 4 5 6 ~])
> `(qeu)`(~(put to a) 7)
{7 6 5 4 2 1 3}

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++tap:to

Queue to list

Produces queue a as a list from front to back.

Accepts

a is a queue.

Produces

A list.

Source

++  tap
  =+  b=`(list _?>(?=(^ a) n.a))`~
  |-  ^+  b
  =+  0                                   ::  hack for jet match
  ?~  a
    b
  $(a r.a, b [n.a $(a l.a)])

Examples

> =a (~(gas to `(qeu @)`~) [3 1 2 4 5 6 ~])
> `*`a
[6 0 2 [4 [5 0 0] 0] 1 0 3 0 0]

> ~(tap to a)
~[3 1 2 4 5 6]

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++top:to

Produce head

Produces the head of queue a as a unit.

Accepts

a is a queue.

Produces

A unit.

Source

++  top
  |-  ^-  (unit _?>(?=(^ a) n.a))
  ?~  a  ~
  ?~(r.a [~ n.a] $(a r.a))

Examples

> =a (~(gas to `(qeu @)`~) `(list @)`[1 2 3 4 5 6 ~])
> ~(top to a)
[~ u=1]

Discussion

An empty queue has no head.

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