Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/dehun/learn-fp

learn-by-doing course/tutorial for functional programming on scala
https://github.com/dehun/learn-fp

applicative comonads course functional-idioms functional-programming functor monad monad-transformers monads monoid scala tutorial typeclasses

Last synced: about 2 months ago
JSON representation

learn-by-doing course/tutorial for functional programming on scala

Awesome Lists containing this project

README 

        
# Learn Functional Programming course/tutorial on Scala  [![Build Status](https://travis-ci.org/dehun/learn-fp.svg?branch=master)](https://travis-ci.org/dehun/learn-fp) [![Build Status](https://travis-ci.org/dehun/learn-fp.svg?branch=answers)](https://travis-ci.org/dehun/learn-fp) #

## Intro ##

This course/tutorial was created with purpose to better understand functional programming idioms using Scala language.

It covers type classes, monoids, functors, applicatives, monads, traversable/foldable, monad transformers, free monad.   

Material is structured as set of stub/unimplemented functions/classes and tests for them.

Your objective is to make all unit tests green. It is learn-by-doing course.



## Example session ##

![Example session](example.gif?raw=true "Example session")



## Inspiration ##

NICTA course was a great and interesting challenge for me to do in Haskell.

I think Scala community will benefit from the similar course.



## Target audience ##

The material in here is quite poor on theoretical/explanation part.

I have tried to link material from other authors that I have found to be good into this course Readme to compensate for this.

Some prior experience with functional idioms is recommended, but not necessary.



## How to start ##

Just git clone this repository and follow steps in progression section.

You can use any IDE and verify your results using `sbt test`. 

For me intellij works best - you can easily run individual tests out of it.

In case if you got stuck - check answers branch.



## Progression ##

It is important to keep the progression - a lot of things depend on each other.

Implementing something = making all tests green for that thing.



### Type classes ###



- Observe general type class pattern in `learnfp/typeclass/TypeClass.scala`.

- Implement `learnfp/typeclass/TotalOrder.scala`

- Implement `learnfp/typeclass/Show.scala`

- Implement `learnfp/typeclass/Eq.scala`

- Extra material: 

  - https://blog.scalac.io/2017/04/19/typeclasses-in-scala.html



### Monoids ###



- Observe general monoid pattern in `learnfp/monoid/Monoid.scala`

- Implement `learn-fp/src/main/scala/learnfp/monoid/ListMonoid.scala`

- Implement `learn-fp/src/main/scala/learnfp/monoid/SimpleMonoid.scala`

- Implement `learnfp/monoid/PairAdditiveMonoid.scala`

- Extra material:

  - Bartosz Milewski: Category Theory 3.1: Examples of categories, orders, monoids

  



### Functors ###



- Observe general functor pattern in `learnfp/functor/Functor.scala`

- Implement `learnfp/functor/Id.scala`

- Implement `learnfp/functor/Maybe.scala`

- Implement `learnfp/functor/List.scala`

- Implement `learnfp/functor/Disjunction.scala`

- Implement `learnfp/functor/Writer.scala`

- Implement `learnfp/functor/State.scala`

- Extra material:

  - http://learnyouahaskell.com/functors-applicative-functors-and-monoids

  - https://thedet.wordpress.com/2012/04/28/functors-monads-applicatives-can-be-so-simple/

  - Bartosz Milewski: Category Theory 6.1: Functors 



### Monads ###



- Observe general monad pattern in `learnfp/monad/Monad.scala`

- Implement `learnfp/monad/Id.scala`

- Implement `learnfp/monad/Maybe.scala`

- Implement `learnfp/monad/List.scala`

- Implement `learnfp/monad/Disjunction.scala`

- Implement `learnfp/monad/Writer.scala`

- Implement `learnfp/monad/State.scala`

- Extra material

  - Brian Beckman: Don't fear the Monad

  - http://eed3si9n.com/learning-scalaz/Monad+transformers.html

  

### Foldable ###



- Implement foldable in `learnfp/foldable/Foldable.scala`



### Applicatives ###



- Observe general applicative pattern in `learnfp/applicative/Applicative.scala`

- Implement `learnfp/applicative/Id.scala`

- Implement `learnfp/applicative/Maybe.scala`

- Implement `learnfp/applicative/List.scala`

- Implement `learnfp/applicative/Disjunction.scala`

- Implement `learnfp/applicative/Writer.scala`

- Implement `learnfp/applicative/State.scala`

- Extra material 

  - https://en.wikibooks.org/wiki/Haskell/Applicative_functors

  - http://eed3si9n.com/learning-scalaz/Applicative.html

  

### Traversable ###



- Implement `learnfp/traversable/Traversable.scala`



### Nested ###



- Implement `learnfp/nested/Nested.scala`



### IO ###



- Implement `learnfp/io/IO.scala` 



### Monad Transformers ###



- Observe general monad transformer typeclass in `learnfp/transformer/MonadTransformer.scala`

- Implement `learnfp/transformer/IdT.scala`

- Implement `learnfp/transformer/MaybeT.scala`

- Implement `learnfp/transformer/WriterT.scala`

- Implement `learnfp/transformer/StateT.scala`

- Extra material: 

  - http://eed3si9n.com/learning-scalaz/Monad+transformers.html



### Free monad ###



- Implement `learnfp/free/Free.scala` and pass all unit tests in `learn-fp/src/test/scala/learnfp/free/FreeTest.scala`

- Extra material:

  - http://blog.krobinson.me/posts/monads-part-2-the-free-monad/

  - https://underscore.io/blog/posts/2015/04/14/free-monads-are-simple.html

  

### Contravariant functor ###



- Observe general contravariant functor pattern in `learnfp/contravariant/ContravariantFunctor.scala`

- Implement `learnfp/contravariant/Show.scala`

- Implement `learnfp/contravariant/Predicate.scala`



### CoMonads ###



- Observe general comonad pattern in `learnfp/comonad/CoMonad.scala`

- Implement `learnfp/comonad/Id.scala`

- Implement `learnfp/comonad/Env.scala`

  

### Bonus ###



- Implement Reader functor, monad, applicative and write unit tests for that

- Implement ReaderT and write unit tests for that

- Implement applicative for monad transformers

- Implement applicative for Free



# What was left out #



- Reader/ReaderT

- Eff



# Bugs/Issues #

In case if find a bug/issue - please report it to https://github.com/dehun/learn-fp/issues or e-mail me on [email protected]  

You also are very welcome to create PR.

  

# Credits #



- Yuriy Netesov - initial implementation

- Extra material references are owned by other authors