Everything you need to know about Kotlin 2.0 🟣

Summary

JetBrains announced over 80 new features in Kotlin 2.0 at a conference in Denmark. Key updates include extensible data arguments with the 'data R' keyword for cleaner API maintenance, guarded conditions in 'when' blocks to avoid repeating variable names, and context-sensitive resolution for shorter code. Other enhancements are explicit backing fields to reduce boilerplate code, string literals improvements, and union types for error handling. These updates aim to increase developer productivity and code safety.

Takeaways

• 🚀 JetBrains announced over 80 new features in Kotlin 2.0 at a conference in Denmark, showcasing the language's rapid growth.
• 🔑 The introduction of 'data R' keyword allows for extensible data arguments, simplifying the addition of new parameters to functions without overloading.
• 📚 Extensible data arguments help in reducing code duplication and improve the maintenance of APIs by consolidating customization options.
• 🔒 'Guarded conditions' in Kotlin 2.0 enable checking multiple conditions in a 'when' block without repeating the variable name, enhancing code readability.
• 🔄 Context-sensitive resolution allows handling of sealed types or enums more concisely by omitting the base class name when the expected type is known.
• 💥 Kotlin 2.0 restricts destructuring declarations to use variable names that match the property names of the data class, improving code consistency.
• 🛡️ Explicit backing fields reduce boilerplate code by allowing the declaration of a single variable to hold both mutable and immutable states, enhancing encapsulation and immutability.
• 📝 String literals and templates in Kotlin 2.0 now support variable references using the '$' symbol, making string manipulation more flexible.
• 🔄 Union types for errors are introduced in Kotlin 2.0 to handle unchecked casts in a type-safe manner, improving code reliability.
• 🧠 Smart casts in Kotlin 2.0 are enhanced to work after logical operators, allowing for more intuitive and error-free code.
• 🔄 The Kotlin compiler now supports operations between long and integer types more safely, reducing the risk of runtime errors.

Q & A

What is the main topic of the video script?

The main topic of the video script is the announcement of over 80 new features and improvements in Kotlin 2.0, along with an introduction to some of the most important updates.

What does the 'data R' keyword in Kotlin 2.0 represent?

The 'data R' keyword in Kotlin 2.0 represents extensible data arguments, which is used to mark a class as a holder of customization arguments, allowing for easier maintenance and functionality extension of APIs.

Why might adding a new parameter to a function like 'lazy column' require a new overload in the current Kotlin version?

Adding a new parameter to a function like 'lazy column' requires a new overload to maintain backward compatibility and to avoid duplicating documentation for all existing parameters, which can introduce a lot of repetition.

What is the purpose of the 'guarded condition' feature in Kotlin 2.0?

The 'guarded condition' feature in Kotlin 2.0 is used to check for multiple conditions inside a 'when' block without repeating the state or variable name, simplifying the code and reducing redundancy.

How does the 'context sensitive resolution' update in Kotlin 2.0 improve code conciseness?

The 'context sensitive resolution' update in Kotlin 2.0 allows handling instances of sealed types or enums directly without repeating the base class name when the expected type is well-known, making the code even shorter.

What is the issue with Kotlin's current destructuring declarations that Kotlin 2.0 aims to address?

In Kotlin 2.0, the issue with destructuring declarations is that variable names cannot differ from the actual property names of the data class object being destructured. Writing custom variable names results in a compile-time error.

What is the benefit of using explicit backing fields in Kotlin 2.0?

Using explicit backing fields in Kotlin 2.0 allows encapsulation of the internal state of an object, control over how the state is modified and accessed, and maintaining immutability from an external perspective while allowing controlled modification internally.

How does the update related to string literals and string templates in Kotlin 2.0 improve the functionality?

The update related to string literals and string templates in Kotlin 2.0 allows referencing variables or properties within a triple-quoted string using a special syntax, making it simpler and more flexible.

What is the significance of introducing Union types for errors in Kotlin 2.0?

The introduction of Union types for errors in Kotlin 2.0 helps in handling multiple types in a type-safe manner, particularly useful for unchecked casts, allowing the compiler to understand the type and automatically cast to an appropriate value.

How does the smart cast improvement after logical operators in Kotlin 2.0 benefit developers?

The smart cast improvement after logical operators in Kotlin 2.0 allows the compiler to infer the closest super type of the variable after a logical operator, enabling developers to invoke functions without issues, making the code cleaner and safer.

What is the impact of the simplification of Kotlin constructs in Kotlin 2.0 on code cleanliness?

The simplification of Kotlin constructs in Kotlin 2.0, such as combining long and integer types with the plus equals operator, allows the compiler to perform necessary conversions automatically, resulting in cleaner and more maintainable code.

Outlines

00:00

🚀 Kotlin 2.0: New Features Overview

The script introduces over 80 new features in Kotlin 2.0, focusing on extensible data arguments with the 'data AR' keyword, which simplifies function overloading and documentation. It also discusses 'guarded conditions' in when blocks, reducing the need for repeating variable names, and context-sensitive resolution for cleaner code. Additionally, Kotlin 2.0 brings updates to destructuring declarations, requiring variable names to match data class property names, and the introduction of explicit backing fields for better state encapsulation and immutability.

05:02

🛠️ Kotlin 2.0: Code Simplification and Smart Casting

This paragraph delves into the simplification of Kotlin code with explicit backing fields, reducing boilerplate code by half. It also covers enhancements to string literals and templates, allowing variable references within triple-quoted strings. The introduction of Union types specifically for error handling aims to mitigate unchecked cast issues, while smart casts after logical operators or in conditions improve code readability and reusability. The updates also touch on making Kotlin constructs simpler and safer, including operations with long and integer types.

10:02

🔍 Kotlin 2.0: Updates and Community Engagement

The final paragraph highlights the numerous updates in Kotlin 2.0, inviting viewers to explore them in detail through a provided link. It encourages feedback on the updates' usefulness and potential impact on productivity. The script concludes with a call to action for likes and comments, emphasizing community engagement and the desire for viewers to share their thoughts on the new features.

Keywords

💡Kotlin 2.0

Kotlin 2.0 is the latest major release of the Kotlin programming language, which is known for its interoperability with Java and its use in Android app development. The video discusses the new features and improvements introduced in this release, emphasizing how they contribute to the language's growth and the efficiency of developers using it.

💡Extensible Data Arguments

Extensible Data Arguments is a new concept introduced in Kotlin 2.0, represented by the 'data R' keyword. It allows developers to create a class that holds various customization arguments, simplifying the maintenance and extension of APIs. The script mentions this feature in the context of avoiding overloads and duplicating documentation when adding new parameters to functions like 'lazy column'.

💡Guarded Conditions

Guarded Conditions is a feature in Kotlin 2.0 that facilitates checking multiple conditions within a 'when' block without repeating the state or variable name. This feature aims to reduce redundancy and improve code readability, as demonstrated in the script with an example where the 'if' keyword is used to specify additional conditions.

💡Context Sensitive Resolution

Context Sensitive Resolution is an enhancement in Kotlin 2.0 that allows for more concise code by handling instances of sealed types or enums directly, without repeating the base class name. The script illustrates how this feature contributes to writing shorter and more readable code.

💡Destructuring Declarations

Destructuring Declarations in Kotlin 2.0 now require variable names to match the property names of the data class being destructured. This change is aimed at reducing errors and improving code consistency. The script provides an example where using different variable names from the property names results in a compile-time error.

💡Explicit Backing Fields

Explicit Backing Fields is a feature introduced in Kotlin 2.0 that simplifies the creation of mutable and immutable variables. It allows encapsulation of the internal state of an object and controlled modification, which is beneficial for maintaining consistency and integrity. The script explains how this feature reduces boilerplate code and enhances code quality.

💡String Literals and Templates

Kotlin 2.0 enhances string literals and templates by allowing the use of variable references within triple-quoted strings using the '$' symbol. This feature provides a more straightforward way to include variables in strings, as mentioned in the script.

💡Union Types for Errors

Union Types for Errors is a feature in Kotlin 2.0 that allows handling multiple error types in a type-safe manner. The script explains that this feature is particularly useful for unchecked casts and helps the compiler understand the types in the code, thereby improving safety and readability.

💡Smart Casts

Smart Casts is a feature in Kotlin that reduces the need for explicit type checks. The script discusses how Kotlin 2.0 improves smart casts after logical operators and within conditions, allowing for more concise and error-free code.

💡Nullable Types

Nullable Types in Kotlin represent the possibility of a value being null. The script mentions that Kotlin 2.0 improves the handling of nullable types, particularly in operations with long and integer types, making the code cleaner and safer.

💡APIs

APIs, or Application Programming Interfaces, are sets of protocols and tools for building software applications. The script discusses how Kotlin 2.0's new features, such as Extensible Data Arguments, can make the maintenance and functionality extension of existing APIs easier.

Highlights

JetBrains announced over 80 new features and improvements in Kotlin 2.0.

Introduction of extensible data arguments with the new 'data R' keyword in Kotlin.

Extensible data arguments help avoid overloads and duplicated documentation for added function parameters.

Guarded conditions in Kotlin 2.0 allow for multiple conditions in a 'when' block without repeating variable names.

Guarded conditions will be introduced in Kotlin 2.1 beta, using 'if' for additional conditions.

Context-sensitive resolution in Kotlin 2.0 simplifies handling of sealed types and enums.

Kotlin 2.0 introduces destructuring declarations limitations, enforcing variable names to match data class property names.

JetBrains plans to add syntax for assigning new names to destructuring properties in future updates.

Removal of component functions for named-based destructuring in Kotlin 2.0.

Explicit backing fields introduced to reduce boilerplate code for mutable and immutable variable pairs.

String literals and templates in Kotlin 2.0 now support variable references with a special syntax.

Union types for errors introduced in Kotlin 2.0 to handle multiple error types in a type-safe manner.

Smart casts in Kotlin 2.0 provide more context-sensitive type information for variables.

Smart cast after logical operators or within a single variable is now possible in Kotlin 2.0.

Kotlin 2.0 allows combining long and integer types with the '+=' operator without compile-time errors.

The Kotlin compiler now performs safe operations before executing code, making constructs cleaner.

The video provides a link in the description for more detailed information on Kotlin 2.0 updates.

The presenter invites viewers to share their thoughts on the updates and their potential impact on productivity.

Transcripts

a couple of days ago on a cotlin

conference in Denmark jet brains has

announced above 80 new features and

improvements that comes with a new

cotlin 2.0 release the language is

growing pretty fast in this video I will

quickly introduce you with some of the

most important updates that you need to

know about stay

[Music]

tuned one of the first things that

caught my attention in this new cotlin

release was an in uction of extensible

data arguments which is represented

through the new data AR keyword in

cotlin yay we got a new keyword right

but what does it mean what problem does

it solve and how can it help us to make

our code more

concise well first let me start from

explaining the current issue that we

have let's take a lazy column composable

for example it's a well-known UI

function with a bunch of different

parameters that are available for a

customization such functions heavily

utilize the use of a parameters with a

default values to avoid a lot of

overloads that are required to cover for

all those

cases but what if we decide to add a new

parameter to this function we would have

to add a new overload to support the

backward

compatibility new overloads also means

that we need to duplicate all the

documentation for all existing

parameters which introduces a lot of

repeating stuff if you take the closer

look at the function definition of a

lazy column you will notice that those

parameters are mostly used to add the

various customization options and that's

where the new extensible data arguments

concept comes into play jetbrains wants

to allow you to create a new class with

a data R keyword to mark that class as a

holder of all those customization

arguments that you may have this can

result in an easier maintenance and

functionality extension of your existing

apis they want to leave a door open for

a library authors to have a full control

over representation of their

arguments by skipping an explicit

creation of such classes at a call site

which means when you call a lazy column

with this a new argument type you don't

have to initialize an additional class

instead you can pass the data AR

properties separately like we did so

far the next great Improvement in a

cotlin 2.0 is called guarded Condition

it's used to help us check for multiple

conditions inside the when block without

repeating the state or the variable

name so far if you wanted to check for a

multiple conditions in a when block you

would have to repeat the variable name

for each separate case but now with the

guarded conditions we don't have to

repeat it anymore the new feature is

going to get introduced with a cotlin

2.1 beta version

and with that in mind we can use an if

keyword to specify an additional

condition all without repeating the

variable name which is

great the previous example that I have

shown you can be improved further more

with a context sensitive resolution

that's another upgrade that we have

received from a cing 2.0 we can handle

instances of a seal types or enams

directly without repeating the Base

Class name when expected type is a well

known this makes our code even more

shorter than

before the next update is about cotlin

destructing

declarations so previously we could

destruct an object of a data class in a

multiple variables where the name of

each variable can be anything you want

but now with cotlin 2.0 you can no

longer write the variable names that are

different from the actual property names

of that same data class object that you

are trying to

distract with a cotl 2.0 if you try to

write custom variable names here instead

of the actual property names then you're

going to get a compile time

error however I have heard that they are

also planning to add some kind of a

special syntax that will allow you to

assign new names to destructing

properties but we'll see how that

goes jetbrains also plan on removing

component functions for a named based

destructuring completely

the next interesting update that you may

have already heard about is an

introduction of explicit backing

Fields the primary purpose of creating

two variables one mutable and private

and the second one immutable and public

is to be able to modify the mutable one

only from within the scope of a single

class without exposing its mutability

outside of the view model for example

that approach has a few benefits like

encapsulation immutability and a

controlled

modification by using backing Fields you

can encapsulate the internal state of an

object which allows you to control how

the state is modified and accessed

exposing an immutable public property

while keeping a im mutable private

property ensures that the external code

cannot modify the property directly

which is maintaining a level of

immutability

from the outside perspective and

controlled modification means that it

allows the class to manage and validate

changes to the property internally which

can be crucial for maintaining

consistency and integrity of the object

State this pattern however introduced

the creation of two different variables

and since we are generally creating and

maintaining a lot of different states in

our project this introduced a lot of

plate code as well luckily with this new

update in a cing 2.0 we can declare a

single variable instead and cut the

boiler plate for almost 50% which is

amazing the new solution provides an

explicit field declaration where we can

hold both mutable and immutable State

mutable state is private and available

only within the scope of the parent

class next there is also an update

related to string literals and string

templates previously if you have used a

triple quoted string in cotlin you

couldn't get the reference of a certain

variables or Properties by using a

dollar symbol it didn't work however

with a cotlin 2.0 we can do exactly that

with this special syntax by adding a $2

symbols before the starting triple

quoted string on the

top simple and easy

the next update in a cing 2.0 is related

to Union types for errors Union types

are a feature in some programming

languages that allows a variable to hold

values of a different types they are

used to describe a value that could be

one of a several types effectively

providing a way to handle multiple types

in a type safe

manner however in this case cotlin

doesn't introduce Union types in general

only for errors in your code as far as I

understand its main benefit should be

for unchecked casts that we have seen so

far in one of those functions like this

one with error Union types we should

mitigate that issue of unchecked cast in

our code with this example right here

you can see that we have created an

error object that will help the compiler

understand the type in our code and

automatically cast that to an appr rate

value while we are here talking about

smart C from a cing 2.0 if you declare a

variable before using it in your if when

or while condition then any information

collected by the compiler about the

variable is accessible in the condition

statement and it's a block for a smart

casting this can be useful when you want

to do things like extract the Boolean

condition into a variable then you can

give the variable a meaningful name

which makes your code a lot easier to

read and easily reuse the variable later

in your code for example in this code

right here we will be able to access an

information about the cat

class we can also produce a multiple

smart casts within a single variable in

this case the first one is from a type

check and the second one is from this is

null or empty function both of them will

be applied to an appropriate block

resulting in a smart

cast smart cast after a logical operator

or are now possible too for example

let's say that we have a one parent

interface and a three child or sub

interfaces previously the compiler

didn't perform any smart C after a

logical operator or so if you check if

the variable is either one of those two

we still couldn't invoke the signal

function and with this new cing compiler

we are now able to infer that this

variable is the closest Super type of

the postpone or decline types which is

the

status therefore we can invoke the

signal function without any

issues pretty

neat the next Improvement I want to

mention here is about making your cting

constructs even simpler and safer than

before like for example we can now

create and combine both long and integer

ER types with this Plus in equal

operator without any compile time

errors because compiler can now dgar

this code and then perform all necessary

conversions by

itself even with nullable types cing

compiler can now dgar this code and make

safe operations before executing this

code which in the end makes your code

more

cleaner so those were some of the most

notable updates for me so far and there

are a lot of more actually so if you

wish to check them in more details I

will leave the link down in the video

description anyhow what's your thoughts

on these new updates do you find them

helpful do you think that they will

increase your productivity even more

comment down below and let me know other

than that don't forget to leave a like

but only if you find this video helpful

thank you for watching

God if I die I'm a legend when they lay

me down to rest