Hey all, I'm not really understanding how to harne...

# announcements

[Austin Paquette]

Hey all, I'm not really understanding how to harness the full power of trailing lambdas, I'm fairly certain it's what I want but I'm also open to being wrong. I am fairly Inexperienced with Kotlin so please take me to school if you need to!

I am trying to mimic behaviour that I noticed in Ktor's HTTP Client when it comes to applying the body parameter, but in my own abstraction of a client for a particular service endpoint.

Basically, I have this function (fluff removed), but point is clear.

sendNotification(listOf("..."), listOf("..."))

This is ultimately fine and works as intended, but I am trying to find a way to explicitly set each of these values. Instead I'd like to do this:

sendNotification() {
    subscriberKeys = listOf("...")
    users = listOf("...")
}

This helps me describe exactly what I need each value to be and then pass them through the implementation, I just don't fundamentally understand the examples provided.

I've tried with some smaller sample code but nothing quite clicks yet. I'll gladly accept links to helpful resources too, I've done a fair amount of searching but nothing has quite illuminated the lightbulb on this.

[Shawn]

1) you should keep most of this in a thread instead of filling the channel, 2) do you really need trailing closures for what you’re trying to do? Have you tried keyword arguments?

sendNotification(
    subscriberKeys = listOf(...),
    users = listOf(...),
)

[Shawn]

I realize this doesn’t exactly answer your question as originally stated—here are some docs on Type-safe builders that should address what you want to learn about https://kotlinlang.org/docs/type-safe-builders.html
https://kotlinlang.org/docs/lambdas.html#function-literals-with-receiver

[Austin Paquette]

Totally fair didn't mean to take up as much space as it did, just wanted to be clear on my initial vision.

I actually had no idea that keyword arguments worked that way, taking a look at how it works that's more than enough to get the point across.

[Shawn]

No worries dude, just something to keep in mind for next time

[nkiesel]

"trailing lambda" is really just syntactic sugar: given a function fun foo(body: () -> Unit), you can call this with foo { ... } instead of foo({ ... }) by applying 2 rules: (1): if the last argument of a function is a lambda, you can move that out of the () when calling the function and (2) if you call a function using "trailing lambda" and that function needs no other parameters than the lambda, you can omit the ()