kotlinlang #arrow-contributors

07/21/2018, 8:46 PM

Eq=>Boolean::class?

07/21/2018, 8:46 PM

no arrow that way

07/21/2018, 8:46 PM

07/21/2018, 8:47 PM

does it have to be an operator? can it not be an infix?

07/21/2018, 8:47 PM

Eq of Boolean::class

07/21/2018, 8:47 PM

yes, that works

07/21/2018, 8:48 PM

the requirement here is that type classes must have a companion object though

07/21/2018, 8:48 PM

otherwise we can do

07/21/2018, 8:48 PM

Eq::class of Boolean::class

07/21/2018, 8:48 PM

works for me. At the moment codegen requires for them to be in an

instances

07/21/2018, 8:48 PM

so I don’t mind that much

07/21/2018, 8:48 PM

07/21/2018, 8:49 PM

only for transitive parameters

07/21/2018, 8:49 PM

I mean, we can fail at compile time if they don't have a companion object

07/21/2018, 8:49 PM

how do you make a companion object of an interface tho

07/21/2018, 8:49 PM

07/21/2018, 8:49 PM

so, something like this will be generated:

07/21/2018, 8:50 PM

okay, apparently interfaces can have companion objects…

07/21/2018, 8:50 PM

did I know this?

07/21/2018, 8:53 PM

@PublishedApi
internal object BooleanEqInstance_ : BooleanEqInstance

@InlineOnly
@JvmName("instanceEq<Boolean>")
inline operator fun KClass<Eq<*>>.plus(type: KClass<Boolean>): Eq<Boolean> = BooleanEqInstance_

07/21/2018, 8:53 PM

oh yeah they can

07/21/2018, 8:54 PM

https://i.imgur.com/0UjJ7o2.gif▾

07/21/2018, 8:55 PM

which allows you to do

val instance: Eq<Boolean> = Eq::class + Boolean::class

07/21/2018, 8:55 PM

so this is one thing, the other is creating extensions for Boolean

07/21/2018, 8:56 PM

Then we can do something like Eq.boolean, boolean being extension field for Eq companion object

07/21/2018, 8:57 PM

the extensions in this case would be:

@InlineOnly
inline fun Boolean.eqv(b: Boolean): Boolean = with(BooleanEqInstance_) { this@eqv.eqv(b) }

@InlineOnly
inline fun Boolean.neqv(b: Boolean): Boolean = with(BooleanEqInstance_) { this@neqv.neqv(b) }

07/21/2018, 8:58 PM

@jereksel the problem with that is that you might have cases where it's ambiguous

07/21/2018, 8:59 PM

it’s a case of

Typeclass.datatype()

Datatype.typeclass()

. For consistency I’d make all of them functions

07/21/2018, 8:59 PM

Datatype

you meah high order?

07/21/2018, 8:59 PM

or any extended type?