Kotlin everywhere

1. Kotlin everywhere

2. Who’s speaking
Rob @ NYT
Boris @
ClearScore
2

3. #CPIT2
sli.do
Join the discussion

4. Where
https://pusher.com/state-of-kotlin

5. Desktop apps
with a little bit of Tornado™

6. ● JavaFX
● Beautiful DSL
● UI + Background thread
● Injection
● REST
● Field validation
● Can work™ with JS
TornadoFX
6

7. tornadofx.io
goo.gl/qSjBPG
goo.gl/gcrZss

8. iOS apps
and Android (but we wanted the WOW moment)

9. Kotlin Native
COMMON
no platform specific
dependencies
class/function declaration
9
PLATFORM
implementations of
platform-dependent
declarations in the common
module
always an implementation
of a single common module
REGULAR
targets specific platform
can be dependency of
platform modules
can depend on platform
modules

10. 10

11. ◇ common module defines
expected declarations
◇ expected declarations never
contain any implementation
code
11
expected

12. 12
actual
◇ platform module provides
actual declarations
◇ actual declarations must
match expected
declarations

13. 13
package org.jetbrains.foo
expect class Foo(bar: String) {
fun frob()
}
fun main(args: Array<String>) {
Foo("Hello").frob()
}

14. 14
package org.jetbrains.foo
actual class Foo actual constructor(val bar:
String) {
actual fun frob() {
println("Frobbing the $bar")
}
}

15. JVM Backend

16. 16

17. Javascript
Both Frontend and Backend!

18. 18

19. 19

20. ◇ You can set and call
everything you want on
properties of this type
◇ Disables compiler checks
(beware of runtime errors)
20
dynamic

21. ◇ Kotlin assumes the
implementation is provided
by the developer (in JS)
◇ The compiler will not
generate JS code for this
function
◇ No auto completion
21
external

22. 22
external fun require(module: String): dynamic
fun main(args: Array<String>) {
val app = require(“express”)
app.get(“/hello”, {req, res ->
res.send(“Hello world!”)
})
}

23. }
23
{
Kotlin wrappers

24. 24
@JsModule(“express”)
external class Express {
fun get(
route: String,
callback: (req: Request, res: Response) -> Unit
)
external class Request
external class Response {
fun send(data: String)
}
}

25. }
25
{
Kotlin wrappers
https://github.com/JetBrains/kotlin-wrappers

26. Thanks!
Any questions?
You can find us at:
◇ @_tiwiz
◇ @borisdamato
26