Enum generated as Java interface

[crmorello]

Just curious if there is a particular reason why Cito enums are generated as separate Java interfaces?
This:

public enum TestEnum { 
    A, 
    B 
}

Generates a separate TestEnum.java file that contains:

public interface TestEnum
{
	int A = 0;
	int B = 1;
}

I would have expected the following since the syntax is almost identical in this case

public enum TestEnum { 
    A, 
    B;
}

[pfusik]

Thank you for this question!

This decision was made long time ago, when Android was avoiding Java enums.
It looks like Android's reasons are now obsolete so I'm going to change cito to emit Java enums.

[pfusik]

How to transpile flags? I'm aware of EnumSet, but how would you transpile:

public enum* Inventory
{
	None = 0,
	Gun = 1,
	Knife = 2,
	Weapons = Gun | Knife,
	Key = 4
}

?

[pfusik]

import java.util.EnumSet;

public enum Inventory
{
	_GUN,
	_KNIFE,
	_KEY;
	public static final EnumSet<Inventory> NONE = EnumSet.noneOf(Inventory.class);
	public static final EnumSet<Inventory> GUN = EnumSet.of(_GUN);
	public static final EnumSet<Inventory> KNIFE = EnumSet.of(_KNIFE);
	public static final EnumSet<Inventory> WEAPONS = EnumSet.of(_GUN, _KNIFE);
	public static final EnumSet<Inventory> KEY = EnumSet.of(_KEY);

	/// The `&` operator.
	public static EnumSet<Inventory> retaining(EnumSet<Inventory> a, EnumSet<Inventory> b)
	{
		EnumSet<Inventory> result = EnumSet.copyOf(a);
		result.retainAll(b);
		return result;
	}

	/// The `|` operator.
	public static EnumSet<Inventory> adding(EnumSet<Inventory> a, EnumSet<Inventory> b)
	{
		EnumSet<Inventory> result = EnumSet.copyOf(a);
		result.addAll(b);
		return result;
	}
}

?

[pfusik]

Ć	Java
f1 == f2	f1.equals(f2)
~f	EnumSet.complementOf(f)
f1 &= f2;	f1 = EnumSet.copyOf(f1); f1.retainAll(f2);
f1 |= f2;	f1 = EnumSet.copyOf(f1); f1.addAll(f2);
f1.HasFlag(f2)	f1.containsAll(f2)
f1 ^ f2 (symmetric difference)	???

[crmorello]

Ah nice, thanks for taking a look into this. The EnumSet solution looks good to me, though I don't write Java often so I'm not an authority on the matter. I think for symmetric difference most people generally rely on a library as there is no built in. There is two different implementations here to get an idea: https://rosettacode.org/wiki/Symmetric_difference#Java

[pfusik]

EnumSet is problematic. Assigning (integer or other enum) values to Java enum is problematic.
For now, I'm going to emit Java enums only for non-flags enums with no assigned values. Other enums will remain interfaces with int constants.