for-comprehension fp-types Kotlin monad-transformers free-monads continuations category-theory functional-programming kotlin-library polymorphism arrow delimited-continuations Shell functional-data-structure recursion-schemes typed-lambda-calculus typeclasses tagless-final monads optics typeclass-derivation
Need help with arrow?
Click the “chat” button below for chat support from the developer who created it, or find similar developers for support.
arrow-kt

Description

Λrrow - Functional companion to Kotlin's Standard Library

4.0K Stars 298 Forks Other 4.5K Commits 111 Opened issues

Services available

Need anything else?

Maven Central Latest snapshot Kotlin version badge

License StackOverflow Twitter

Λrrow is a library for Typed Functional Programming in Kotlin.

Arrow aims to provide a lingua franca of interfaces and abstractions across Kotlin libraries. For this, it includes the most popular data types, type classes and abstractions such as

Option
,
Try
,
Either
,
IO
,
Functor
,
Applicative
,
Monad
to empower users to write pure FP apps and libraries built atop higher order abstractions.

Use the list below to learn more about Λrrow's main features.

Curated external links

If you have a blog post, talk, or upcoming event on Arrow, please considering opening an issue or PR to add to the collection over at the Arrow Media repo.

About this repository

This repository orchestrates the global configuration and checks of the Λrrow libraries and other related repositories.

| | | SSH | HTTPS | | - | ------- | -------------- | ---------------- | | | Λrrow Core |

[email protected]:arrow-kt/arrow-core.git
|
https://github.com/arrow-kt/arrow-core.git
| | | Λrrow Fx |
[email protected]:arrow-kt/arrow-fx.git
|
https://github.com/arrow-kt/arrow-fx.git
| | | Λrrow Optics |
[email protected]:arrow-kt/arrow-optics.git
|
https://github.com/arrow-kt/arrow-optics.git
| | | Λrrow Meta |
[email protected]:arrow-kt/arrow-meta.git
|
https://github.com/arrow-kt/arrow-meta.git
| | | Λrrow Incubator |
[email protected]:arrow-kt/arrow-incubator.git
|
https://github.com/arrow-kt/arrow-incubator.git
| | | Λrrow Integrations |
[email protected]:arrow-kt/arrow-integrations.git
|
https://github.com/arrow-kt/arrow-integrations.git
| | | Λrrow UI |
[email protected]:arrow-kt/arrow-ui.git
|
https://github.com/arrow-kt/arrow-ui.git
| | | Λrrow Check |
[email protected]:arrow-kt/arrow-check.git
|
https://github.com/arrow-kt/arrow-check.git
| | | Λrrow Ank |
[email protected]:arrow-kt/arrow-ank.git
|
https://github.com/arrow-kt/arrow-ank.git
| | | Λrrow Site |
[email protected]:arrow-kt/arrow-site.git
|
https://github.com/arrow-kt/arrow-site.git
| | | Λrrow Examples |
[email protected]:arrow-kt/arrow-examples.git
|
https://github.com/arrow-kt/arrow-examples.git
|

Find more details in Move arrow repository content to multi-repo.

Join Us

Arrow is an inclusive community powered by awesome individuals like you. As an actively growing ecosystem, Arrow and its associated libraries and toolsets are in need of new contributors! We have issues suited for all levels, from entry to advanced, and our maintainers are happy to provide 1:1 mentoring. All are welcome in Arrow.

If you’re looking to contribute, have questions, or want to keep up-to-date about what’s happening, please follow us here and say hello!

Find more details in CONTRIBUTING.

Setup

Next development version

If you want to try the last features, replace

0.11.0
by
1.0.0-SNAPSHOT
in the following guideline.

JDK

Make sure to have the latest version of JDK 1.8 installed.

Android

Arrow supports Android out of the box starting on API 21 and up.

We'll be working on a Arrow-Android integration module that adds some helpers and integrations.

Gradle

Basic Setup

In your project's root

build.gradle
, append these repositories to your list:
allprojects {
    repositories {
        mavenCentral()
        jcenter()
        maven { url "https://dl.bintray.com/arrow-kt/arrow-kt/" } 
        maven { url "https://oss.jfrog.org/artifactory/oss-snapshot-local/" } // for SNAPSHOT builds
    }
}

Add the dependencies into the project's

build.gradle
:
Λrrow Core
apply plugin: 'kotlin-kapt'

def arrow_version = "0.11.0" dependencies { implementation "io.arrow-kt:arrow-core:$arrow_version" implementation "io.arrow-kt:arrow-syntax:$arrow_version" kapt "io.arrow-kt:arrow-meta:$arrow_version" }

Λrrow Core + Λrrow Optics
apply plugin: 'kotlin-kapt'

def arrow_version = "0.11.0" dependencies { implementation "io.arrow-kt:arrow-optics:$arrow_version" implementation "io.arrow-kt:arrow-syntax:$arrow_version" kapt "io.arrow-kt:arrow-meta:$arrow_version" }

Λrrow Core + Λrrow Fx
apply plugin: 'kotlin-kapt'

def arrow_version = "0.11.0" dependencies { implementation "io.arrow-kt:arrow-fx:$arrow_version" implementation "io.arrow-kt:arrow-syntax:$arrow_version" kapt "io.arrow-kt:arrow-meta:$arrow_version" }

Λrrow Core + Λrrow Optics + Λrrow Fx
apply plugin: 'kotlin-kapt'

def arrow_version = "0.11.0" dependencies { implementation "io.arrow-kt:arrow-fx:$arrow_version" implementation "io.arrow-kt:arrow-optics:$arrow_version" implementation "io.arrow-kt:arrow-syntax:$arrow_version" kapt "io.arrow-kt:arrow-meta:$arrow_version" }

Other libraries

Here is the complete library list for a more granular dependency set-up.

Additional Setup

For projects that wish to use their own

@higherkind
,
@optics
, and other meta programming facilities provided by Arrow the setup below is also required:

Add the dependencies into the project's

build.gradle
apply plugin: 'kotlin-kapt' //optional
apply from: rootProject.file('gradle/generated-kotlin-sources.gradle') //only for Android projects

def arrow_version = "0.11.0" dependencies { ... kapt "io.arrow-kt:arrow-meta:$arrow_version" //optional ... }

gradle/generated-kotlin-sources.gradle
```groovy apply plugin: 'idea'

idea { module { sourceDirs += files( 'build/generated/source/kapt/main', 'build/generated/source/kapt/debug', 'build/generated/source/kapt/release', 'build/generated/source/kaptKotlin/main', 'build/generated/source/kaptKotlin/debug', 'build/generated/source/kaptKotlin/release', 'build/tmp/kapt/main/kotlinGenerated') generatedSourceDirs += files( 'build/generated/source/kapt/main', 'build/generated/source/kapt/debug', 'build/generated/source/kapt/release', 'build/generated/source/kaptKotlin/main', 'build/generated/source/kaptKotlin/debug', 'build/generated/source/kaptKotlin/release', 'build/tmp/kapt/main/kotlinGenerated') } } ```

BOM file

To avoid specifying the Arrow version for every dependency, a BOM file is available:

    implementation platform("io.arrow-kt:arrow-stack:$arrow_version")

implementation "io.arrow-kt:arrow-core"
implementation "io.arrow-kt:arrow-fx"
implementation "io.arrow-kt:arrow-syntax"
...

Example of use

Maven

Basic Setup

Add to your

pom.xml
file the following properties:
xml

    1.4.0
    0.11.0

Add the dependencies that you want to use

xml

    io.arrow-kt
    arrow-core
    ${arrow.version}


    io.arrow-kt
    arrow-syntax
    ${arrow.version}

Enabling kapt

Enable annotation processing using Kotlin plugin:

xml

    org.jetbrains.kotlin
    kotlin-maven-plugin
    ${kotlin.version}
    
        
            kapt
            
                kapt
            
            
                
                    src/main/kotlin
                
                
                    
                        io.arrow-kt
                        arrow-meta
                        ${arrow.version}
                    
                
            
        
        
            compile
            compile
            
                compile
            
            
                
                    src/main/kotlin
                
            
        
        
            test-compile
            test-compile
            
                test-compile
            
        
    

BOM file

To avoid specifying the Arrow version for every dependency, a BOM file is available:

  
    
      
        io.arrow-kt
        arrow-stack
        ${arrow.version}
        pom
        import
      
    
  
  
    ...
  

License

Copyright (C) 2017 The Λrrow Authors

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.