LambdaCast

This time we discuss the way data tends to be structured in functional languages and some of the similarities with databases and REST.

Episode 22 patrons:

Jason Sooter

Jamie Rolfs

Christian Hamburger

Daniel Svensson

Di Wen

Iulian Bojinca

Jonathan Fishbein

Nathan Sculli

Nels Wadycki

Paul Naranja

Peter Tillemans

Thomas Varney

Tyler Harper

weila wei

Dawn (שחר)

Show Notes:

CPPCast: http://cppcast.com/

John Soo - Sharing in Haskell

https://wiki.haskell.org/Sharing

https://stackoverflow.com/questions/1105765/generating-fibonacci-numbers-in-haskell

Alejandro’s link to Phantom Types article: https://www.objc.io/blog/2014/12/29/functional-snippet-13-phantom-types/

FP Chat Slack Community: https://fpchat-invite.herokuapp.com

Intro/Outro music is "Lively Lumpsucker" by Kevin MacLeod (incompetech.com)

Licensed under Creative Commons: By Attribution 3.0 License

You may have seen generics in C#, Java, or Swift but there are a lot of very useful patterns using generics that rarely get used in an OO context. In this episode, we explore Type Parameters (aka generics) from a functional perspective and how using them can improve the structure of your applications.

Episode 21 patrons:

Scott Smith

Joel McCracken

Hakon Rossebo

Seth Utecht

Christophe Pereira da Conceicao

E. Mulder

Show Notes:

Add a type parameter video: https://www.youtube.com/watch?v=BHjIl81HgfE

Matt Parson's follow-up post: http://www.parsonsmatt.org/2017/04/08/maybe_use_a_type_parameter.html

Stephen’s Twitter: https://twitter.com/S11001001

Type Parameter example in Scala: https://typelevel.org/blog/2015/09/21/change-values.html

FP Chat Slack Community: https://fpchat-invite.herokuapp.com

Lazy evaluation is not normally something you hear programmers discussing but there is a lot of power available if you know how to use it. This episode we'll examine the differences between lazy and strict evaluation and look at use cases for laziness.

Episode 20 patrons:

Marcus Nielsen

Steven Loe

Ted Yavuzkurt

Michael Meyers

Szymon Beczkowski

Parl Naranja

Paul Brabban

Jason Sooter

Show Notes:

Memoization: https://codeburst.io/functional-memoization-in-javascript-adec62508bd0

Using IEnumerable in C# to generate an infinite sequence: https://brianreiter.org/2011/01/14/ienumerable-is-lazy-and-thats-cool/

FP Chat Slack Community: https://fpchat-invite.herokuapp.com

Logan walks us through what his experience has been starting a JavaScript project in a functional style and using the best FP tools he can get in the JavaScript ecosystem.

Episode 19 patrons:

Nathan Sculli

Lee Beck

David Joyner

Nihohit

Charles Winebrinner

FP Chat Slack Community: https://fpchat-invite.herokuapp.com

Monads, the promised land of functional programming. Or at least with all the hype they'd better be! Come join the cast as we demystify this overhyped structure that has become an indispensable part of many functional programmer's toolkits.

Episode 18 patrons:

Pluton

Tim Buckley

Huge shout out to Marcus Nielsen

Show Notes:

bind :: m a -> (a -> m b) -> m b

Example of do syntax vs using bind aka >>=:

main = do

foo <- doMonadyThing

foo2 <- doOtherMonadyThing foo

pure (whatever foo foo2)

main = doMonadyThing

>>= (\foo -> doOtherMonadyThing foo

>>= (\foo2 -> pure (whatever foo foo2))

)

Extracting a value from a Maybe

extract :: Just Int -> Int

extract foo = case foo of

Just num -> num

Nothing -> 0

Railroad oriented programming talk by Scott Wlaschin

fsharpforfunandprofit.com/rop/

FP Chat Slack Community: https://fpchat-invite.herokuapp.com

Building on the power of functors we examine a few scenarios where a normal Functor is problematic. Fortunately, there is a closely related structure known as an Applicative Functor that can provide the capabilities to solve a broader range of problems.

Episode 17 patrons:

Chad Wooley

David Keathley

Andre Carvalho

Show Notes:

Coconut programming language: http://coconut-lang.org/

Hack nights instead of presentations: http://tech.noredink.com/post/142283641812/designing-meetups-to-build-better-communities

class Functor f => Applicative f where

pure :: Applicative f => a -> f a

ap :: Applicative f => f (a -> b) -> f a -> f b

Example of applicative usage:

pure (+) <*> Just 3 <*> Just 2 -- this results in Just 5

(+) <$> Just 3 <*> Just 2 -- this is the same as above

liftA2 (+) (Just 3) (Just 2) -- alternate form using lift instead of infix operators

Going deeper down the category theory rabbit hole, we explore one of the most common and useful abstractions in the functional programming world. You're likely already familiar with Functors but just didn't know it yet.

Episode 16 patrons:

Chris Krycho

Tyler Harper

George Webster

Show Notes:

Functor

map :: (a -> b) -> f a -> f b

Bifunctor

bimap :: (a -> b) -> (c -> d) -> f a c -> f b d

Profunctor

dimap :: (a -> b) -> (c -> d) -> f b c -> f a d

Phil Freeman's talk on Profunctors: https://www.youtube.com/watch?v=OJtGECfksds

Join us as we discuss the FP community. FP has a reputation as harsh and impenetrable but is that really the case? What can you do to make FP a more inviting place?

Episode 15 patrons:

Chris Lopes

Gabe Johnson

Randy Shepherd

Noel Waghorn

Correction: I incorrectly stated that one of the Recurse Center Social rules was “No Feigned Ignorance” it is actually “No Feigned Surprise”

Show Notes:

Cloud Haskell - http://haskell-distributed.github.io/tutorials/1ch.html

Recurse Center Social Rules - https://www.recurse.com/manual

Lambdaconf COC - http://fantasyland.institute/initiatives/COC.html

Moonconf COC - http://maitria.com/coc

Haskellbook - haskellbook.com

NY Haskell speaker guide - https://docs.google.com/document/d/1065iwf918SDotEPc0q9TWP_F1haVyeK90MSaBg3IOn8/edit

Spa day instead of pub meetup - https://twitter.com/sehurlburt/status/875848925529243648

Steven Syrek - https://twitter.com/sjsyrek

The kind of type system a functional language uses has a large impact on the way you use that language. In this episode we discuss the tradeoffs involved in using a static or dynamic language.

Our patreon sponsors this month:

Javier Troconis

Andrew Newman

Derek Morr

Olov Johansson

Show Notes:

Philip Wadler Talk: https://www.infoq.com/presentations/category-theory-propositions-principle

Denotational Design

Scott Wlaschin Poker Implementation

https://exit.sc/?url=https%3A%2F%2Ffsharpforfunandprofit.com%2Fddd%2F

Conal Elliot presentation on Denotational Design

https://www.youtube.com/watch?v=bmKYiUOEo2A

Our recomendation for a DDD book

https://www.amazon.com/Patterns-Principles-Practices-Domain-Driven-Design/dp/1118714709

Algebraic Data Types (ADTs) are one of the most distinguishing features of statically typed functional languages. Come learn why they exist, how you can use them, and how they change your design.

Join the FP community at http://fpchat.com

Support us on Patreon at http://www.patreon.com/lambdacast

Follow us on Twitter: http://twitter.com/lambdacast

Show Notes:

Denotational Design with the example of a Poker game

https://fsharpforfunandprofit.com/ddd/