References to Interfaces maybe shouldn't be pointers?

[flyinprogrammer]

What I expected:

Given a class that extends an abstract class, like Person:

• pkl-go/codegen/snippet-tests/input/Classes.pkl

  Line 49 in 4541166

  open class Person extends Being {

• pkl-go/codegen/snippet-tests/output/bugholder/Person.pkl.go

  Line 4 in 4541166

  type Person interface {

When you reference a Person in another class as nullable, like with Bug:

• pkl-go/codegen/snippet-tests/input/Classes.pkl

  Lines 81 to 83 in 4541166

  	class Bug {
  	/// The owner of this bug.
  	owner: Person?

• pkl-go/codegen/snippet-tests/output/bugholder/Bug.pkl.go

  Line 12 in 4541166

  Owner *Person `pkl:"owner"`

Then, we should generate a reference to the Person interface because interfaces themselves are pointers and nil by default.

What I have observed:

Then, we generate a reference to a pointer of Person:

pkl-go/codegen/snippet-tests/output/bugholder/Bug.pkl.go

Lines 10 to 12 in 4541166

	type Bug struct {
	// The owner of this bug.
	Owner *Person `pkl:"owner"`

What is the problem?

When we use a Bug and access the Owner, we have to dereference the value to access the data and create named constructors to use our structs:

https://github.com/flyinprogrammer/pkl-go-bananas/blob/7210f20ca30593f9d0ebad3665bcec1ebed6a128/main.go#L9-L28

func NewPerson() earth.Person {
	return &earth.PersonImpl{
		FirstName: "Alan",
		LastName:  "Scherger",
	}
}
func main() {
	alanPerson := NewPerson()

	atlasMoth := earth.Bug{
		Name:  "Addison",
		Owner: &alanPerson,
	}

	fmt.Println("Type of alanPerson: ", reflect.TypeOf(alanPerson))
	fmt.Println("Type of atlasMoth: ", reflect.TypeOf(atlasMoth))
	me := *atlasMoth.Owner
	fmt.Println("Type of me: ", reflect.TypeOf(me))
	fmt.Println("atlasMoth Owner GetFirstName: ", (*atlasMoth.Owner).GetFirstName())
	fmt.Println("me PersonImpl FirstName: ", me.(*earth.PersonImpl).FirstName)

}

This is very awkward.

---

Maybe we can add logic to stop adding a pointer to interfaces. That could be super hard. I don't know 😢 but I can come back to this later if no one else does; I don't have the time at this moment.

[bioball]

Makes sense. We can probably add an option to prefer non-pointers.

[thomaspurchas]

@flyinprogrammer does #83 address your concerns here?

[flyinprogrammer]

@thomaspurchas I believe so! I'm more than happy to validate, too, post-merge!