`it` cannot be added, because it can change a mean...

# announcements

[orangy]

it cannot be added, because it can change a meaning of some it already used

[Ruckus]

Out of curiosity, if you could go back and change the design from the get-go, would you use the 1.3 design or an have when use a more lambda-ish syntax?

when (getData()) { data ->
   data is Thing -> ...
   ...
}

[Ruckus]

Which could then use it

[orangy]

I didn’t try to design it from ground up, so I don’t have an answer. But personally, I’d try to make it possible so that when is actually a function 🙂

[elizarov]

Support for when-like functions is still a possibility, imo. Can be retrofitted in a backwards-compatible way. I find use-cases for that from time time.

[Ruckus]

@orangy Fair enough. That could be interesting.

[Ruckus]

@elizarov Do you mean like the coroutine select expressions?

[elizarov]

things like that. but not only that.

[elizarov]

It is about alegebraic types with internally encapsulated structure.

[elizarov]

So, we support it for product types. If you have an encapsulated color you can destruct it into (r, b, g) via componentX operators

[elizarov]

But we don’t have that for sum types

[Ruckus]

Ah, okay. Is that something that could be worked around with the new KClasses.sealdSubclasses?

[louiscad]

@elizarov Would a custom when like be just a function, or a class, or an interface? Do you think it may be considered in a future Kotlin version? I also had several use cases where I wish I could define a when like construct

[orangy]

No design, no plans, nothing yet

[orangy]

But while we are here, I often want to implement interfaces anonymously in short form like this:

widget.addListener { 
     move -> …
     click -> …
     cancel ->  …
}

where move, click and cancel are methods of the interface that I need to pass to addListener.
Multi-lambda if you wish.

[Ruckus]

@orangy I've wanted something very similar every time I have to do any Swing development.