Can someone please tell me how I can see declarations of ref kotlinlang #announcements

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Title

s

Saiedmomen

08/23/2019, 6:38 PM

Can someone please tell me how I can see declarations of reflection types like

KFunction

and

KSuspendFunction1

? I have imported imported

kotlin-reflect

but I have to manually import them and IDE inspection tools like go to declaration and search in path can't find their declaration

m

Marc Knaup

08/23/2019, 6:40 PM

I think the compiler generates them on-the-fly as needed 🤔 What do you need the source for?

s

Saiedmomen

08/23/2019, 6:50 PM

I'm trying to findout why I can't pass a non suspending block to a higher order function that expects a suspend block. Wanted to read up a bit before posting it to discuss.kotlinlang

s

streetsofboston

08/23/2019, 6:55 PM

A

() -> T

type is not a ‘sub-class’ of (i.e. ‘assignable to’) a

suspend () -> T

type… They are entirely separate.

E.g.

var suspendLambda : suspend () -> Int = suspend { 5 }
var lambda : () -> Int = { 5 }

fun main() {
    suspendLambda = lambda // ERROR Type Mismatch
}

s

Saiedmomen

08/23/2019, 7:10 PM

yeah but I think any normal function is also a suspend function

s

streetsofboston

08/23/2019, 7:14 PM

No, not true… A normal function can be called inside a suspend function, a suspend function cannot be called in a normal function. This doesn’t mean that a normal function ‘is-a’ suspend function…..

But, I agree, it would be nice if there were some automatic conversions from

() -> T

to

suspend () -> T

by the compiler when needed. (like

() -> T

to

KFunction<T>

and such…)

m

Marc Knaup

08/23/2019, 7:15 PM

What are you actually trying to achieve? You can provide overloads for

suspend

and non-suspend functions.

There’s the same problem with passing a

suspend

function to a non-suspend argument of an inline function:

suspend fun doSomething(transform: suspend (Int) -> String) =
    listOf(1,2).map(transform)

Also doesn’t work 😕 But this works:

suspend fun doSomething(transform: suspend (Int) -> String) =
    listOf(1, 2).map { transform(it) }

Would be nice to have more automatic conversions indeed.

s

Saiedmomen

08/23/2019, 7:19 PM

yeah Anton. Thats exactly what I'd like to see. Sorry for my lack of fluency.

s

streetsofboston

08/23/2019, 7:20 PM

No need to be sorry 🙂 You have legitimate questions.

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