Algebraic Data Types (ADT) in Scala | Rock the JVM

[@CoreyMinter]

The illegal state not represented is a huge aspect that people need to appreciate. I see a lot of "stringly typed" programming. It seems to be very common in Python and with beginner programmers. For example as map keys or Python dict keys). With ADTs a huge class of runtime errors are not possible.

[@rockthejvm]

Yep

[@ValinorFP]

Wonderful video, as always. Thank you, Daniel and long live Scala!

[@Yupppi]

Rock the JVM? That's the Marshall head from the 2010's, somewhat popular. Worth rocking.

[@ibrahimkoz1983]

Always-valid domain model and avoiding primitive obsession are directly relevant to this concept.

[@i6g7f]

nicely crafted demonstration. Very helpful to promote use of ADTs in Scala

[@rockthejvm]

So glad it's useful!

[@mourikogoro9709]

The best ADT tutorial!!

[@rockthejvm]

Glad it helped!

[@miloventimiglia8547]

Once more a brilliant video! Keep up the good work!

[@rockthejvm]

Thank you!

[@ZoYaBoBo]

Thank you for explaining ADT, you are awesome )

[@matteozampieri6392]

Just bought access to your Advanced Scala course on Udemy! I am also eyeing the Spark Streaming 3.0 for my job :p

[@rockthejvm]

Nice! Enjoy!

[@Minimingus]

Best explanation ever

[@rockthejvm]

Glad you liked it!

[@Lumintorious]

I love the explanation, I understood Product and Sum for the first time so thank you for that. My brain is wired towards extensibility so I even though I understand the purpose of ADTs for types that are universally finite (True and False / Up, Down, Left and Right), it's hard for me to understand why you would not use an extensible pattern for the weather type. Weather can be LOTS of things that can cause a whole array of feelings: Tornado, Sandstorm, Blizzard, Foggy etc. and maybe you just want to provide the functionality for these structures/objects, but let client code provide their types. Let's say we have an application like the one you provided for weather requests/responses, but we want to make it open to extension, closed to change (open for external addons/plugins), how would you implement this system to let client code provide their own VolcanicThunderStorm (silly example I know) weather type with it's own feeling? I feel like Scala is about the best of both worlds of FP + OOP and I want to understand the pros and cons of both. Thanks in advance.

[@rockthejvm]

Legit point. The weather example was really simplified to prove a point (which no doubt you understood). As your logic gets increasingly complicated, you will probably want to expand on your ADTs, e.g. instead of a Sum type you might want to use a Product type to support many more possible values.

[@wojciechgradzki100]

Would be good if we have ADTs part 2 with smart constructors etc

[@rockthejvm]

Yep - coming soon!

[@juanjdlt]

great Videos! thanks a lot. an observation. the function naiveFeeling() shouldn't be receiving the NaiveWeather type alias as the argument type, instead of String? greetings

[@rockthejvm]

Sure - you can use both. But you got the idea :D

[@victorgomez335]

Great video, you rock!!

[@estebanmarin002]

❤ thanks for this

[@parthnayi786]

Can you make one video on HTTP4s CRUD

[@kyotin1]

it's awesome video!

[@rockthejvm]

Glad you liked it!

[@omarojmb]

you rock

[@rockthejvm]

:D

[@barslo]

Hi, great videos. I have learnt from them a lot. I have a suggestion about what you could do for the next video. What is the difference between _ and * in type parameter. Here is a post from stackoverflow stackoverflow.com/questions/61686150/difference-between-star-and-underscore-in-type-parameter but it is hard to understand for newcomers. If you could explain it, but in a more simplified way.

[@rockthejvm]

Check out the type lambdas video - the * is used for that purpose, but you won't need it anymore in Scala 3.

[@utubebroadcastme]

is this scala 3 ? why not try the new syntax ?

[@rockthejvm]

Wanted to make this accessible to all. Will increasingly use the new syntax in future videos.

[@utubebroadcastme]

@@rockthejvm I just feel that's what most people are 'googling' this days, plus the videos will age better ... great series nonetheless