Default value for parameter in multiple lambda input function

Language Design
1

I’m trying to be able to run this code:

class test {

    fun test() {
        MinOreo { print("Oreo and above")}
        MinOreo ({print("Oreo and above")},{print("Below Oreo")})
    }
}

For this I’ve specified this function:

fun <T> T.MinOreo(block: T.() -> Unit, blockElse: T.() -> Unit = {}) = doForMin(block, blockElse, Api.OREO)

It doesn’t work. The first “MinOreo” block above fails to compile:

 No value passed for parameter 'block'

If I add this it then starts to work:

fun <T> T.MinOreo(block: T.() -> Unit) = doForMin(block, {}, Api.OREO)

Shouldn’t it work with the default parameter version of the function alone?

Thanks in advance!

2

When you omit the parenthesis, the lambda should be for the last parameter of the function.

So when you call MinOreo {...} you are actually calling MinOreo(no value here, {...}).
If you call MinOreo({...}) it should work in this case.

1 Like
3

Oh, I see! So using

fun <T> T.MinOreo(blockElse: T.() -> Unit = {}, block: T.() -> Unit) = doForMin(block, blockElse, Api.OREO)

will work! :slight_smile: Was not aware of that particularity. Thank you very much!