Is it legit to have a dedicated interface containi...

# getting-started

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Is it legit to have a dedicated interface containing a function with a lambda with a receiver to be implemented by third parts?

interface Action {
//    interface DSL Builder
    operator fun<T> invoke(block: T.() -> Unit)
}

Because I cant seem to properly override in the implementation..

[Ruckus]

class ActionImpl : Action {
    override fun <T> String.invoke(block: T.() -> Unit) {
        // Do something
    }
}

Just a standard implementation, unless I misunderstood your question.

[elect]

If I try:

object V2 : Action {
    operator fun invoke(block: Builder.() -> Unit) {..}
    class Builder

I get on object V2

Object 'V2' is not abstract and does not implement abstract member public abstract operator fun <T> invoke(block: T.() → Unit): Unit defined in kyge.Action

while on the function itself:

Accidental override: The following declarations have the same JVM signature (invoke(Lkotlin/jvm/functions/Function1;)V):

public abstract fun <T> invoke(block: T.() → Unit): Unit defined in kyge.actions.checkout.V2

public final operator fun invoke(block: checkout.V2.Builder.() → Unit): Unit defined in kyge.actions.checkout.V2

Ps: it isn't an extension function anymore

[Ruckus]

You may want to move the generic to Action, not invoke.

interface Action<T> {
    // interface DSL Builder
    operator fun invoke(block: T.() -> Unit)
}

object V2 : Action<Builder> {
    override fun String.invoke(block: Builder.() -> Unit) {
        // Do something
    }

    class Builder
}

Otherwise invoke needs to be able to handle any generic value

[elect]

ah nice

[elect]

thanks

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one thing though, I'm trying to move the invoke function inside the Action interface, but I don't know how I can call block from that..
I'm thinking what the best design could be

[elect]

maybe adding a val t: T in the interface?

[Ruckus]

I'm not sure what you're asking. Maybe show how you want to use it, and we can work backward from there?

[elect]

I'm writing a DSL helper to generate github action yaml files.
The i-th action, such as uploadArtifact, should just declare the builder
Then the implemented Action<T> interface would initialize the yaml writing