https://github.com/ctongfei/gizmos

Cats typeclass-based collection library for Scala (Trees, Graphs, Multimaps and more!)
https://github.com/ctongfei/gizmos

cats collections graph scala tree

Last synced: 2 months ago
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Cats typeclass-based collection library for Scala (Trees, Graphs, Multimaps and more!)

• Host: GitHub
• URL: https://github.com/ctongfei/gizmos
• Owner: ctongfei
• License: mit
• Created: 2015-05-22T17:06:58.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2017-10-04T04:38:11.000Z (over 7 years ago)
• Last Synced: 2023-08-02T00:37:08.991Z (over 1 year ago)
• Topics: cats, collections, graph, scala, tree
• Language: Scala
• Homepage:
• Size: 924 KB
• Stars: 13
• Watchers: 1
• Forks: 4
• Open Issues: 12
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
## Poly-collection

Poly-collection is a Scala collection framework that aims to provide an alternative to the standard

 Scala collection framework. It provides a large range of collection classes, and differs from

 the standard collection framework in several ways:

 

  - Full support for **graphs, trees, multisets, multimaps** and others with various functional operators defined on them.

  

  - **Based on algebraic typeclasses through the Typelevel Scala family projects

   [Cats](https://github.com/typelevel/cats), [Algebra](https://github.com/typelevel/algebra) and [Spire](https://github.com/non/spire)**

    (`Eq`/`Order`/...). This means the equivalence relation / hashing function for sets / maps 

     can be customized via arbitrary typeclass instances.

     

  - **Lazy by default**: Higher-order transformational functions are nearly always executed in a non-strict manner:

   functions like `map`, `filter`, `flatMap` are nearly always evaluated lazily (like Spark). This allows chain application like 

   `xs map f filter g reduce h` to be much faster than the standard library.

  

  - **Returning-same-trait principle**: Instead of the uniform-return-type principle of the Scala standard collection

   library, Poly-collection returns the most fined-grained trait possible without much performance loss.

    For example, a `map` applied on an `ArraySeq` would return a read-only view, 

    or a lazy `IndexedSeq` instead of a strict `ArraySeq`.

  

  - **`Map`s and `Set`s are not `Iterable`s**, instead, `map.pairs` or `set.keys` are. The nonsensical behavior of `zip`/`tail` etc. 

  for Sets/Maps in Scala is removed. `map.zip` now means zip-by-keys. 

  - Various algorithms / data structures provided out of the box: binary search, disjoint sets, Fenwick trees, etc.

  

    - A fully-fledged `search` subpackage that enables the execution of common search algorithms (BFS, DFS, A*, etc.) on very

   generic state spaces (of course lazily!).

   

    - Caching utilities: `LRUCache`, `Memo`.

  

Implicit conversions from/to Scala & from Java collections to Poly-collections are provided by importing the

objects `poly.collection.conversion.{FromJava, FromScala, ToScala}`.

Poly-collection is currently in alpha stage and is progressing into the 0.1 release.

```scala

libraryDependencies += "me.tongfei" %% "poly-collection" % "0.1.0"

```

#### Pending Scala issues

 - [SI-2509: Contravariant implicits](https://issues.scala-lang.org/browse/SI-2509) influences the use of contravariant typeclasses `Eq`/`Order`/`Hashing`.

 - [SI-2712: Higher-order unification](https://issues.scala-lang.org/browse/SI-2712) influences the `to` method on `Traversable`s when piping to a `BitSet`/`DenseIntKeyedMap`.

  

#### Todo

 - Remove Spire from the dependencies.