Alternative to the suffix .val and .ref in JEP 401: Primitive Objects

Brian Goetz brian.goetz at oracle.com
Wed May 12 14:09:48 UTC 2021



On 5/11/2021 10:51 PM, Anderson Vasconcelos Pires wrote:
> Hi guys,
>
> I saw Michael Kuhlmann's e-mail [1] where he quotes:
>
> "The suffixes .ref and .val don't fit into our concept of class names, they
> look ugly and can easily be mixed up."
>
> I have no complaints about them. But I believe it would be better, *if
> possible*, not to use them.

I know this isn't what you meant, but it is definitely better not to use 
them if they can be avoided!  The design of the feature works hard to 
minimize the cases where someone actually has to say .ref or .val; these 
are escape hatches that most users should not use regularly.

> I believe it would be better to use the operator "?" instead of .ref.
> because it can be used when the "null safety" feature comes to Java. :)

We have discussed this extensively, but the reasons you cite are exactly 
why we *cannot* use `?` here, and that is -- because it means something 
else.  Ref/val refer to how the object is stored (flat vs indirect), not 
to its value set.  But by calling it `Foo?`, it would be almost 
impossible for users to see this as anything other than non-nullable 
Foo.  But identity classes, such as ArrayList, cannot be flattened (they 
need their identity for mutation), and yet the notion of "non-nullable 
reference to ArrayList" makes perfect sense.  So while `?` and `ref` 
seem to have a lot in common, they are not the same thing, and trying to 
pun them together would only be confusing.




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