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https://github.com/j-maas/elm-ordered-containers
OrderedDict and OrderedSet that remember the order of insertion.
https://github.com/j-maas/elm-ordered-containers
elm
Last synced: 11 days ago
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OrderedDict and OrderedSet that remember the order of insertion.
- Host: GitHub
- URL: https://github.com/j-maas/elm-ordered-containers
- Owner: j-maas
- License: bsd-3-clause
- Created: 2021-09-26T14:43:55.000Z (about 3 years ago)
- Default Branch: master
- Last Pushed: 2021-09-26T14:46:26.000Z (about 3 years ago)
- Last Synced: 2024-10-27T13:13:30.979Z (about 2 months ago)
- Topics: elm
- Language: Elm
- Homepage: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/
- Size: 25.4 KB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# elm-ordered-containers
[](https://github.com/j-maas/elm-ordered-containers/actions)
[](https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/)
[](#maintenance)
[`OrderedDict`] and [`OrderedSet`] that remember the order of insertion.
The default implementations, [`Dict`] and [`Set`], do not keep track of their item's ordering. [`OrderedDict`] or [`OrderedSet`], by contrast, will respect the insertion order when converting them to a [`List`] or iterating over their items (using [`foldl`][`OrderedDict.foldl`], [`foldr`][`OrderedDict.foldr`], or [`partition`][`OrderedDict.partition`]).
## Examples
```elm
import OrderedSet
import Set
-- Remembers insertion order
OrderedSet.empty
|> OrderedSet.insert 2
|> OrderedSet.insert 1
|> OrderedSet.insert 3
|> OrderedSet.toList
--> [ 2, 1, 3 ]
-- Orders by keys
Set.empty
|> Set.insert 2
|> Set.insert 1
|> Set.insert 3
|> Set.toList
--> [ 1, 2, 3 ]
```
```elm
import Dict
import OrderedDict
-- Remembers insertion order
OrderedDict.empty
|> OrderedDict.insert 3 "first"
|> OrderedDict.insert 1 "second"
|> OrderedDict.insert 2 "third"
|> OrderedDict.toList
--> [ ( 3, "first" ), ( 1, "second" ), ( 2, "third" ) ]
-- Orders by keys
Dict.empty
|> Dict.insert 3 "first"
|> Dict.insert 1 "second"
|> Dict.insert 2 "third"
|> Dict.toList
--> [ ( 1, "second" ), ( 2, "third" ), ( 3, "first") ]
```
## Comparison to `Dict` and `Set`
The API purposely includes all functions from the regular [`Dict`] and [`Set`] with the exception for the ["Combine"](https://package.elm-lang.org/packages/elm/core/latest/Dict#combine) functions (e.g., [`union`][`Dict.union`], [`diff`][`Dict.diff`], etc.). Those are left out, because combining ordered collections does not have a single obvious solution. You can always write custom combination functions for your use case!
In addition to the regular API there is a method for efficiently converting back to a regular collection, namely [`OrderedDict.toDict`] and [`OrderedSet.toSet`].
## How it works
The [`OrderedDict`], in addition to a plain [`Dict`], keeps a [`List`] of all the keys in the order they are inserted.
This means that we sacrifice some space, but get the performance of [`Dict`] for its ["Query"](https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedDict#query) operations, while only introducing minor overhead to the rest.
As an alternative, [`pzp1997/assoc-list`](https://package.elm-lang.org/packages/pzp1997/assoc-list/latest/) stores only a list while providing a [`Dict`]-like interface.
## History and contributors
Originally, this package was based on [rnon's `ordered-containers`](https://github.com/rnons/ordered-containers) and updated for Elm 0.19. Later, it was merged with [wittjosiah's `elm-ordered-dict`](https://github.com/wittjosiah/elm-ordered-dict) and rewritten to handle re-insertion in a clearly documented way.
Previously, this package was called [`y0hy0h/ordered-containers`](https://github.com/j-maas/ordered-containers), but after a rename of my GitHub account I had to recreate this package as `j-maas/elm-ordered-containers`.
[`OrderedDict`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedDict
[`OrderedDict.foldl`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedDict#foldl
[`OrderedDict.foldr`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedDict#foldr
[`OrderedDict.partition`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedDict#partition
[`OrderedDict.toDict`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedDict#toDict
[`OrderedDict.toList`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedDict#toList
[`OrderedSet`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedSet
[`OrderedSet.toSet`]: https://package.elm-lang.org/packages/j-maas/elm-ordered-containers/latest/OrderedSet#toSet
[`Dict`]: https://package.elm-lang.org/packages/elm/core/latest/Dict
[`Dict.union`]: https://package.elm-lang.org/packages/elm/core/latest/Dict#union
[`Dict.diff`]: https://package.elm-lang.org/packages/elm/core/latest/Dict#diff
[`Dict.map`]: https://package.elm-lang.org/packages/elm/core/latest/Dict#map
[`Set`]: https://package.elm-lang.org/packages/elm/core/latest/Set
[`List`]: https://package.elm-lang.org/packages/elm/core/latest/List
## Maintenance
This project is passively maintened. I intend to respond to issues and pull requests, but am not dedicating time to develop new features.