if (item.p == null) { } else { /* item.p is known to be not null here */ }

should work then.

As in, in the else branch you can use

item.p

as if it were non-null

Without any extra operators

Indeed

Assuming both

item

and

item.p

are vals

ok

it works

thanks

I think…. The reason many people keep asking it is… We have this very nice way to check nullability with

?

and we want to use it instead of

if(item.p == null)

.. it is less verbose… but when we need the

else

it is not so intuitive the current option.

Just to mention. You can also do:

item.p?.let {
            println("executed if not null")
        } ?: run {
          println("executed if null")
        }

The safe-invoke operator

?.

is mostly useful if you are interested in the return value of something. E.g.

val myValue = thing?.value ?: defaultValue

- which is very much less verbose.

But for unit methods like println a plain-old if-else is just fine, in my opinion. Things like Kingsley posted are just confusing imho.

if

statement is something I never liked, but I quite enjoy

if

expression in Kotlin. I barely use

?. ?:

.

@diesieben07 I agree

?. ?:

isn't the nicest piece of code. I only fixed the original code posted by Julio. However, this also has it's own pros 🙂

?.

and

?:

are great, but only if you have simple values. if you need to calculate an expression in the branches if-else is nicer

All this is very opinion-based though 😄

when

would be my goto at that point

I never use

if

. Only

when (condition) {
    true -> { ... }
    false -> { ... }
}

🧌

ha

Scala has a graph collection type, has anyone done one in Kotlin? any interest?

Guava has one. Use that?

ah, lemme have a look .. thanks!

wow that thing looks dope, I used JUNG a long time ago, guy who did that is the lead, Kotlin could probably add some cool stuff to it.. operators or infix methods would be cool..

Yep! You could a lot with Kotlin to the API interaction.

is there any way I can get the type parameter of a generic class

Foo<T>

? It obviously cannot be reified...

nice one. i never thought if that 😛

Hey, I would like to have domain that ends with .kt. But there is no such top-level domain. Maybe JetBrains is interested in registering it and provide it to be sold by domain registration companies?

Why is that? Is there any way to link a getter method with a component method? If yes, I could read the isMarkedNullable property from the component method.

i ran into something regarding extensions that i’m curious about. if i create an extension property inside a class, i’m unable to reference it. i.e.

class Person(val state: State = State.SINGLE) {
    val State.isSingle: Boolean
    	get() = this == State.SINGLE
    
    enum class State {
        SINGLE, MARRIED
    }
}
val john = Person()
print(john.state.isSingle) // Unresolved reference: isSingle