why can't functions defined as such: ```fun foo() ...

# getting-started

[Hullaballoonatic]

why can't functions defined as such:

fun foo() = true

be referenced as such:

val bar: () -> Boolean = foo

?

or conversely:

interface Foo {
    val bar: () -> Boolean
}

object Bar : Foo {
    override fun bar() = true // nope. why not?
    override val bar = { true } // yep
}

[Dias]

because ( )->Boolean is function that returns boolean while true IS boolean

[Adam Powell]

one is a function and the other is a property holding a function reference

[Hullaballoonatic]

i thought all functions WERE properties in the jvm?

[Adam Powell]

not in a way that is significant here

[Adam Powell]

kotlin properties are implemented as jvm methods generally, so more like the other way around for this case

[Adam Powell]

you can get a function reference using :: if you need one

[Hullaballoonatic]

righto, thanks for reminding me of that

[Adam Powell]

also a common gotcha in this area is that foo::bar != foo::bar - they're different instances

[Adam Powell]

so be careful if you're trying to collectionOfFunctionReferences.remove(foo::bar)