[Schematic] Create a constructor with parameters

[toth-istvan-zoltan]

Create a constructor that makes it possible to pass the field values directly.

Right now we have to set the field after the instance has been created:

Data().also {
    it.field = "hello"
}

There are two possible patterns to make the code above clearer:

Direct Constructor Parameters

In this case the compiler plugin generates a constructor with all fields.

Data(field = "hello")

Pros:

• usual, common way in Kotlin
• makes it possible to pass more than one parameter in one line

Cons:

• noisy code, parenthesises, equals, commas
• unnecessary code, this might be considerable in size if there are many fields / classes
• code completion does not work that well with parameters as there is no prefix to provide the context for the name

Builder Function

In this case the compiler plugin adds a constructor that has a function parameter. This is equivalent to ().also { } but it is much more clean.

Data {
    field = "hello"
}

Pros:

• clearer syntax
• smaller code
• code completion works with it. or this.

Cons:

• cannot set two parameters in one line
• might feel a bit unusual

[toth-istvan-zoltan]

The constructor approach has to wait until IntelliJ 2024.2 as KMP + K2 won't be supported in 2024.1.

[toth-istvan-zoltan]

The builder function approach is already implemented. It needs adding the companion object manually but that's only because IDEA does not support K2 KMP yet.

For schematics with generics:

    companion object : SchematicCompanion<SelectField<Any,Any>> {
        @Suppress("UNCHECKED_CAST")
        @JvmName("genericInvoke")
        operator fun <VT,OT> invoke(builder : SelectField<VT,OT>.() -> Unit) : SelectField<VT,OT> =
            (newInstance() as SelectField<VT,OT>).apply(builder)
    }