Support of default value for parameter in Kotlin

Current Behavior

When we use the annotations to set argument, the default value from kotlin declaration is not supported.

With the current system, the command bellow cannot be executed when the player doesn’t define the values for args :

@CommandMethod("test [x] [y] [z]")
@CommandDescription("Test command")
suspend fun testCmd(
        player: Player,
        @Argument("x") x: Double = player.location.x,
        @Argument("y") y: Double = player.location.y,
        @Argument("z") z: Double = player.location.z
) {
 println("parameters : $x $y $z")
}

If the user doesn’t add an argument, a null value will be used to set the arguments.

Effectively, in the @Argument, there is a String to define the default value, but in the most cases, it’s not enough.

Expected Behavior

The command defined above can be used if the user writes : /test /test 1 /test 1 2 /test 1 2 3

[solonovamax]

To add on to this:

As per the docs, you can check if it’s optional by checking KParameter#isOptional. If it is optional, then it can be omitted when invoking KFunction#callBy.

It seems there is no way to get what the default value is via the kotlin reflection api, however you can still use the default without knowledge of what it is.

[solonovamax]

If someone wants to go ahead and implement this, then it could probably become a part of cloud. It would have to go in some new module cloud-kotlin/cloud-kotlin-default-annotations or something (similar to the couroutine support module)

That’s why I proposed something like cloud-kotlin/cloud-kotlin-core (in hindsight, I wasn’t that clear about it)

And, @Distractic, look at SuspendingExecutionHandler and its references.