Hi, one question: What is the difference between declaring a function as a val vs declaring it as a ...

# android

[zceejkr]

Hi, one question:
What is the difference between declaring a function as a val vs declaring it as a fun on a class?
I read somewhere that when calling from Java, the one defined with val becomes cumbersome to use. Is that still the case?

[gildor]

Property will just look as a getter from Java (with is or get prefix), but you also can rename it using JvmName

[gildor]

So nothing cumbersome

[zceejkr]

so to call it I would need to do something like obj.getFun().invoke(args) vs obj.fun(args)?

[gildor]

No real difference on Kotlib side, only semantics a bit different, you can check official style guide, it have some recommendations when use properties when functions

[gildor]

No, your example is incorrect

[gildor]

Obviously you cannot use properties with parameters

[gildor]

Property may be used only as replacement for a getter without arguments

[gildor]

Your example above looks that property foo returns lambda, not just value, it's valid itself, but not as replacement for fun(args)

[gildor]

So simple comparison would be:
val foo = 1
In Java would be obj.getFoo()

[zceejkr]

I see, I think I understand. But what is the difference between fun(args) and a returned lambda that captures the “this” keyword of the object it is a property of?

[zceejkr]

Calling the fun or the lambda should do the same thing no?

[zceejkr]

In any case thanks for the help.

[Alowaniak]

Using a val which returns a function type to use as a normal function is kind of a weird style I would say
It might make sense if you use it as a value more often than immediately invoking?

[zceejkr]

So the reason I want to use it so that I can use destructuring in the arguments XD. As I understand you cannot do that in a fun?

[Alowaniak]

Hmyea it's currently not possible to do destructured params
I personally don't think I would use your lambda val approach though
You can just do a destructured declaration on the first line of the function

[zceejkr]

I see. Well thank you for your help 🙂

[gildor]

if you use it as a value more often

True, but in this case client may decide and just wrap to lambda on call site or use property reference syntax

[gildor]

destructuring in arguments

Just use local variable for destructuring, do not pollute caller's API with unnecessary lambda call