[lworld] RFR: object methods in VM for lworld value type

[John Rose]

On May 7, 2018, at 6:21 AM, David Simms <david.simms at oracle.com> wrote:
> 
> Sorry for the delayed reply, inline...
> 
> On 27/04/18 23:55, Karen Kinnear wrote:
>> Mr Simms,
>> 
>> Yay! Thank you so much for doing the vm changes for Object methods for -Xint.

+100

>> 
>> Question on functionality:
>> 1) Cloneable - this is different than we had originally discussed - so I should bring this to an EG discussion -
>> hopefully for when you are there
> 
> Sure thing. So there is a debate, choices would be that values...
> 
> * May be Cloneable, but may not override clone method
> * Implicitly Cloneable, but may not override clone method (personally
>   like this one)
> * Disallow Cloneable (current patch)

I'd prefer to disallow Cloneable for now.  Either we'll discover a good use for it,
and we can allow it then, or (more likely) we'll never discover a good use
for it, and save confusion.  It seems to me that Object.clone makes sense
only for an object whose fields you can set to new values, while maintaining
the object identity.  That's not a value, so Object.clone should throw an
exception for values. (Again, unless we discover some still-unknown
use of such a thing.  Not holding my breath.)

— John