Bringing pattern matching to Dart 

⛱ Summary 1:54 Multiple Returns 6:09 Control Flow in Argument Lists 8:26 JSON Destructuring 10:28 Usable Switches 13:43 Object Destructuring 15:28 Functional Style Coding

Switch expressions are a great addition! Love them in C# and really appreciate them in Dart now!

Thank you Bob (and of course the rest of the Dart team) for finally bringing this and tuples(err, records) to the language. I know I bugged you all about these features a lot all the way back in 2019. This goes to show that Dart at 3.0 will be the most improved language over the last five years

Thanks for your hard work, Bob, and to everyone on your team! Really looking forward to playing with these features 😃

Dang -- switch case pattern matching is awesome. Very impressed!

Thank you for all these improvements! Architecture and structure in dart projects it's every new feature more powerful, clean, and beautiful! Coming from Swift, pattern matching and sealed unions is a crucial language features, and I've been missing that a lot! Thanks again!! Happy and can't wait to try all this!🤩

Ah, ADTs! I've liked Dart before, but all these features really make it way better. The language deserves better than to be regarded as merely "the language Flutter apps are written in" - I think it ticks pretty much all the boxes of what I want in a language and how it can be deployed.

Bob! I learned how compliers work from your book in my senior year compiler course, and now watching you talk about ASTs in the real world is so fulfilling ☺ thank you for all the hard work and an amazing language 💯

Can't wait for Dart 3 to ship! :D Great work all of you

Thanks bob and rest of the team, excited for it!

Damn, this just made 2023 the best year 🔥

I simply love it! This is so useful in so many ways! Thanks for your hard work!!

At last! I've been wanting comparison in switches since Dart 1. Thanks guys! 👍

Such an amazing job by the Dart team, thank you!

Finally, tuples, and switch returning value like Rust. this is great !

Thank for your amazing work dart folks!

Wow, json pattern matching is amazing! It will simplify work with json.

Great work and presentation. This all looks amazing.

Just one word. Amazing!!!!💙

This is awesome... Im falling in love with Dart after so many years in Typescript (won't even mention Javascript) Land. Thank you.

We love this man! now we can make function return error and exception, same as golang and rust!

12:42 YESSS!!!! THIS IS SO AWESOME!!! OH THANK YOU DART TEAM FOR SWITCH AS EXPRESSION, ILYSM!!! ❤❤❤❤

Some of these features are very practical!

I LOVE THIS!! Thanks Dart team!!!

I'm already drooling. Exciting times!

That's really incredible! Today I've just started reading his book and for my surprise, i click in a Flutter video and guess who is hosting? The GOAT himself 👏🏻👏🏻

Hey, we got Bob Nystrom on our team! I love his Game Programming Patterns book. This is so cool 💪🏾

Wow. Just wow. Can't wait!

I can already see pattern matching and sealed classes optimising my current code. Thanks!

Is so amazing to see the Dart lang developer are also music instrument developer

I cannot believe how exited I am for these features. (Thx Bob for explaining it so well!) Is this how people feel when watching tv and their sports team is winning?

Awesome stuff! Thanks

Man... that's... just... beautiful!!

this some awesome stuff cant wait :)

This is so cool. I love it.

Dudes got a pretty sick setup

i appreciate your work

This is 🔥🔥!!

Crafting Interpreters is the best book I have ever read

This is one of the awesome things I was missing in Dart. Now I'm hopefully waiting for Pipes to be part of Dart as well, so we can make really awesome and readable codebases that Dart deserves.

So excited for conditional arguments

Nice voice quality, ty !

Incredible!

Functional programming was always my favourite

it is amazing, thank you!

awesome!!!

Beautiful

I love it!!!! ❤️ 😍

I like this guy

Love everything about this, except the $1 and $2 indexing for records, gives me "bad feelings". Love it, can't wait!

Awesome!

2:00 Multiple Returns 6:22 Control Flow In Argument Lists 10:28 Usable Switches 13:36 Object Destructuring 15:30 Functional-Style Programming

That's great news :)

It's easy to make a compiler now!

Isn't the last mentioned part "functional-style programming", where we are using the sealed classes in switch case operations, the same as doing "if else" with some compiler sugar? or do they generate an enum in the background for matching the right type? (It's a performance question, do we have the casting overhead on all checks?)

I think I will try to move case expressions to where case statements are allowed as it is much more readable. I love the case statements now, they remind me of my favourite language Ada. I love the data validation options. Ada has a Valid check for records. Pattern matching seems more flexible but can you get it wrong?

Sounds interesting

Finally! In 2023 we finally can use `when` like statement that was added in Kotlin in around 2012)

thanks

For ADTs I would have liked the enums with associated values approach from Swift more instead of subclassing. Haskells handels them beautifully as there is not difference between enum and class/struct. But then you have all this OO in other languages and somehow need to cope with it. Kotlin also uses subclassing as a solution, it is a little clumsy, but it works. For Dart < 3 I implemented classes, that have an enum for the case and a bunch of optional variables - only one filled for the appropriate case - which would be tedious, if I wasn't using Sourcery for generating all this. It is good to finally support ADTs in any way.

Cool! Two questions: 1) Does this essentially make enums unnecessary? I understand that backwards compatibility may mean that they stay in the language. 2) Is Haskell style pattern matching supported, allowing to match both parts and the whole thing? Haskell working example: Input: let a@(b : c) = [1, 2] in (a,b,c) Output: ([1,2],1,[2])

Ugh, I just got schooled around unnecessary switch breaks. You mean to tell me I didn't need to use it all these time... they are quite annoying. Lol

What about Static meta programming?

I really like Dart to get more populair for general computing, like a more robust Typescript alternative

With pattern matching soon we will see new generic features and Prisma-like ORM. This is amazing.

can we use records as tuple for passing data to riverpod providers using family?

So much Gold in Dart

I don't understand how "when" is different from "&&", how to "case" the if, and how :key works, is that the name of the return value?

Can Records be extracted to a Typedef?

What font is used in this slides?

nothing about destructuring assignment ?

I would rather be able to use Rust with Flutter.

Will there be any stable framework for dart backend?

Sounds great, but would have expected something closer to Haskell or Rust to be able to finally get rid of some of the weird codegen for proper BLoC implementations

Still waiting for union types

1. destructuring variables and objects just -stealed- borrowed from Kotlin :), 2. that “awesome” proposal about …() for widget parameters is really ugly, 3. destructuring json looks cool, 4. switch returning a result looks great (thanks Kotlin)

When Dart adopts Rust features 🔥🔥

Норм боб

ranges

who is using pattern and records in their code

Why naming tuples "records"? To confuse users of other languages? You go C# way in naming things and this is not something good.

Rust

as F# lover I can say that some of this is pretty ugly.... but am happy that it is coming. in case am using Dart (I hope not honestly) by the time 3.0 comes along I would definitely be happy about it. this is definitely couple of years too late tho

Very good presentation, however I'm saddened that Dart is falling in the same trap than C#: over burdening the language with syntactic sugar, functional elements etc to 1) appease the 5% of language snobs that demand these features and 2) justify the Dart team salaries. Dart isn't my main language so I don't code frequently in it. It started as a very simple language that wasn't getting in my way. But every time I come back to it more useless stuff has been added. Sometimes I spend more time thinking about the language than my code. More isn't better.

Cool! Thanks for your job! w.r.t. for loop over Map.entries, I think it makes more simple and intuitive to just yield Record (key, value) than MapEntry. Anyway, can't wait for Dart 3.0 on stable channel!

YES, finally. Thank You! It never ceases to amaze me how close Dart is to Python in many respects. For me personally that is a massive positive. Getting sidetracked a bit further Python even has a GUI library (widget wrapper) that seems to borrow somewhat from Flutter -- PySimpleGUI.