Re: What happened to the "mutable struct" debate?

[Timo Kinnunen]

I think that’s too early to say because we don’t know how boxing of values will be implemented.









-- 
Have a nice day,
Timo.

Sent from Windows Mail





From: Vitaly Davidovich
Sent: ‎Friday‎, ‎January‎ ‎23‎, ‎2015 ‎17‎:‎12
To: Timo Kinnunen
Cc: valhalla-dev at openjdk.java.net, Rezaei, Mohammad A.





The point is to avoid allocation! :)

sent from my phone

On Jan 23, 2015 11:11 AM, "Timo Kinnunen" <timo.kinnunen at gmail.com> wrote:




Pass-by-ref is easily emulated by boxing a mutable struct and then operating on the boxed struct.









-- 
Have a nice day,
Timo.

Sent from Windows Mail





From: Vitaly Davidovich
Sent: ‎Friday‎, ‎January‎ ‎23‎, ‎2015 ‎17‎:‎00
To: Rezaei, Mohammad A.
Cc: valhalla-dev at openjdk.java.net





If mutable structs are not allowed to be passed by ref, then one is more
likely to lose writes as the struct is passed through a method chain.
There's no *necessity* per say, but the danger zone is expanded.

The by-ref would be useful for immutable structs as well when you want to
avoid copying costs for a largish struct.

On Fri, Jan 23, 2015 at 10:54 AM, Rezaei, Mohammad A. <
Mohammad.Rezaei at gs.com> wrote:

> >Very much so.  This is indeed Big Strike #1 against them; this is a new
> >big complexity that Java (platform and developers) have not had to deal
> >with.
> >
>
> I don't really see why mutable structs would necessitate pass by
> reference. Java developers are used to pass by value semantics and there is
> a well-known, but admittedly ugly pattern for pass by reference (use an
> array or mutable wrapper).
>
> The reference question comes up even in all-final value types. But I'll
> pose that question in a separate thread.
>
> Thanks
> Moh
>