> For the complete documentation index, see [llms.txt](https://docs.urbit.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.urbit.org/hoon/stdlib/2o.md).
# 2o: Normalizing Containers
Mold generators for common container types including maps, sets, queues, jars, and jugs.
## `+jar`
`$mold` generator. A `+jar` is a `+map` of `+list`.
Produces the `$mold` of a `+map` from `key` to lists of `value`.
#### Accepts
`$key` is a `$mold`, and is the type of the `+map` key.
`$value` is a `$mold`, and is the type of items in the lists. The lists are the values in the `+map`.
#### Produces
A `$mold`.
#### Source
```hoon
++ jar |$ [key value] (map key (list value))
```
#### Examples
```
> `(jar @t @ud)`(malt ~[['foo' ~[1 2 3]] ['bar' ~[4 5 6]]])
{[p='bar' q=~[4 5 6]] [p='foo' q=~[1 2 3]]}
```
#### Discussion
See also: [`+ja`](/hoon/stdlib/2j.md#ja), [`+by`](/hoon/stdlib/2i.md), [`+map`](#map), [`+list`](/hoon/stdlib/2b.md)s.
***
## `+jug`
`$mold` generator. Produces a `+jug`, which is a `(map key (set value))`.
#### Accepts
`$key` is a `$mold`, and is the type of the `+map` key.
`$value` is a `$mold`, and is the type of items in the `+set`s. The `+set`s are the values in the `+map`.
#### Produces
A `$mold`.
#### Source
```hoon
++ jug |$ [key value] (map key (set value))
```
#### Examples
```
> `(jug @t @ud)`(malt ~[['foo' (silt ~[1 2 3])] ['bar' (silt ~[4 5 6])]])
{[p='bar' q={5 6 4}] [p='foo' q={1 2 3}]}
```
#### Discussion
See also: [`+ju`](/hoon/stdlib/2j.md#ju), [`+by`](/hoon/stdlib/2i.md), [`+map`](#map), [`+set`](#set).
***
## `+map`
A `+map` is a [treap](https://en.wikipedia.org/wiki/Treap) of key-value pairs.
Produces the `$mold` of a `+map` from `key` to `value`.
#### Accepts
`$key` is a `$mold`.
`$value` is a `$mold`.
#### Produces
A `$mold`.
#### Source
```hoon
++ map
|$ [key value]
$| (tree (pair key value))
|=(a=(tree (pair)) ?:(=(~ a) & ~(apt by a)))
```
#### Examples
```
> ? *(map @t @ud)
nlr([p=@t q=@ud])
{}
```
```
> `(map @t @ud)`(malt ~[['foo' 1] ['bar' 2] ['baz' 3]])
{[p='bar' q=2] [p='baz' q=3] [p='foo' q=1]}
```
#### Discussion
See also: [`+by`](/hoon/stdlib/2i.md).
***
## `+qeu`
Queue.
`$mold` generator. An ordered [treap](http://en.wikipedia.org/wiki/Treap) of items.
Produces the `$mold` of a queue of `$item`.
#### Accepts
`$item` is a `$mold`.
#### Produces
A `$mold`.
#### Source
```hoon
++ qeu
|$ [item]
$| (tree item)
|=(a=(tree) ?:(=(~ a) & ~(apt to a)))
```
#### Examples
```
> `(qeu @ud)`(~(gas to *(qeu @ud)) ~[1 2 3 4 5])
{5 4 3 2 1}
```
#### Discussion
See also: [`+to`](/hoon/stdlib/2k.md#to).
***
## `+set`
Set.
`$mold` generator. A `+set` is an unordered [treap](http://en.wikipedia.org/wiki/Treap) of items.
Produces the `$mold` of a `+set` of `$item`.
#### Accepts
`$item` is a `$mold`.
#### Produces
A `$mold`.
#### Source
```hoon
++ set
|$ [item]
$| (tree item)
|=(a=(tree) ?:(=(~ a) & ~(apt in a)))
```
#### Examples
```
> `(set @ud)`(silt ~[1 2 3 4 5])
{5 1 2 3 4}
```
#### Discussion
See also: [`+in`](/hoon/stdlib/2h.md).
***
---
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