Bringing pattern matching to Dart
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- Опубликовано: 24 янв 2023
- Records and pattern matching are two of the largest features coming in Dart 3.0. I'll talk about what they are, what they're useful for, and how they harmonize with the rest of the Dart language.
Speaker: Bob Nystrom
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Switch expressions are a great addition! Love them in C# and really appreciate them in Dart now!
⛱ 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
Dang -- switch case pattern matching is awesome. Very impressed!
Thanks for your hard work, Bob, and to everyone on your team! Really looking forward to playing with these features 😃
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
Oh, and I loved Crafting Interpreters
Oh, and thank you for value semantics! That really makes my day. Now only value classes are missing 😉
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 💯
what is the name of the book?
@Safius Silat Crafting Interpreters
@@AnthonyBullard thank you
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!🤩
Thanks bob and rest of the team, excited for it!
Can't wait for Dart 3 to ship! :D Great work all of you
I simply love it! This is so useful in so many ways! Thanks for your hard work!!
Damn, this just made 2023 the best year 🔥
At last! I've been wanting comparison in switches since Dart 1. Thanks guys! 👍
Such an amazing job by the Dart team, thank you!
Great work and presentation. This all looks amazing.
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.
Yes! I love dart so much. I wish more people appreciated it outside of Flutter :)
Thank for your amazing work dart folks!
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 👏🏻👏🏻
Finally, tuples, and switch returning value like Rust. this is great !
Wow, json pattern matching is amazing! It will simplify work with json.
Just one word. Amazing!!!!💙
12:42 YESSS!!!! THIS IS SO AWESOME!!!
OH THANK YOU DART TEAM FOR SWITCH AS EXPRESSION, ILYSM!!! ❤❤❤❤
Some of these features are very practical!
We love this man! now we can make function return error and exception, same as golang and rust!
I LOVE THIS!! Thanks Dart team!!!
I'm already drooling. Exciting times!
This is awesome... Im falling in love with Dart after so many years in Typescript (won't even mention Javascript) Land. Thank you.
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?
Crafting Interpreters is the best book I have ever read
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
Hey, we got Bob Nystrom on our team! I love his Game Programming Patterns book. This is so cool 💪🏾
Awesome stuff! Thanks
this some awesome stuff cant wait :)
Wow. Just wow. Can't wait!
This is so cool. I love it.
Dudes got a pretty sick setup
Man... that's... just... beautiful!!
Functional programming was always my favourite
So excited for conditional arguments
Nice voice quality, ty !
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.
You can use pipe semantics via operator overloading. Not an exact fix..
@@yonoseespanol can you to exemplify this approach ?
2:00 Multiple Returns
6:22 Control Flow In Argument Lists
10:28 Usable Switches
13:36 Object Destructuring
15:30 Functional-Style Programming
i appreciate your work
This is 🔥🔥!!
it is amazing, thank you!
Incredible!
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])
Love everything about this, except the $1 and $2 indexing for records, gives me "bad feelings". Love it, can't wait!
It's on purpose. If you're not using destructuring to access the properties without names, you better give them proper names, otherwise it's going to be confusing regarding of whether it's $1, _1, first, second, etc.
Having positional access as an option is quite sensible
@@qG0L0r6W but why use dollar sign and not just numbers?
Why it's just 1 or 2 dollars... quite cheap if you ask me
@@andreygritsay762 I also wonder why start at 1 and not at 0 as is usual in programming
awesome!!!
Beautiful
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 love it!!!! ❤️ 😍
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?
I like this guy
Finally! In 2023 we finally can use `when` like statement that was added in Kotlin in around 2012)
Awesome!
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.
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
That's great news :)
Sounds interesting
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 we use records as tuple for passing data to riverpod providers using family?
I see no reason why not, I think they're going to be very useful for this indeed.
thanks
Can Records be extracted to a Typedef?
I really like Dart to get more populair for general computing, like a more robust Typescript alternative
What about Static meta programming?
will come after Dart 3. From the issue they say they will probably release a beta of metaprogramming later this year
@@jonathan-dias What do you think will static meta programming will help a lot of developers.
@@msh_dev definitely.
With pattern matching soon we will see new generic features and Prisma-like ORM. This is amazing.
What font is used in this slides?
So much Gold in Dart
nothing about destructuring assignment ?
Will there be any stable framework for dart backend?
Still waiting for union types
I would rather be able to use Rust with Flutter.
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
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)
Норм боб
When Dart adopts Rust features 🔥🔥
Actually, these are features that have existed in various languages, such as the ML family of languages, for a long time. I think what we're seeing is a case of modern programming languages converging to support the same set of great features that have arisen in different languages at different times over the past 50 years or so.
ranges
who is using pattern and records in their code
Rust
Why naming tuples "records"? To confuse users of other languages? You go C# way in naming things and this is not something good.
Because they are not tuples
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.
lmao cope
If it isn't your main language why do you care
I think the feature added will be useful for sure
@@xmanreturn The fact it's not my main language doesn't mean I don't use it. And it's quite confusing when I do use it.
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!
Ideally, yes, but that would require a potentially breaking change to the Map interface, which is harder. We have ideas on how to make this even nicer.
@@m00ni In my opinion, there are two possibilities; add a new getter 'records' to Map or MapEntry inherits Record (K, V),
but the former would be duplicated method, while the latter, I don't know whether it returns (key, value) by inheriting.
I'm looking forward to your ideas on next announcement!!
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.