Returning const ref (structs) in D

[Rob T]

On Saturday, 24 November 2012 at 22:01:32 UTC, Stian wrote:
> Is the compiler sophisticated enough that is it able to avoid 
> the copying. For instance, if i have a struct Matrix4x4 a = 
> node.getTransformation() and use a for whatever, but never 
> alter it, will it be able to avoid the copy? What if i declare 
> it const or immutable? Do i have to use a pointer to it?

You may want to read through this thread to help understand how 
the move/copy semantics work, this part can be difficult to 
understand and appreciate

http://forum.dlang.org/thread/cwywtkycjljdnclqtpqr@forum.dlang.org

> After doing some small stuff in D I am not impressed by the 
> mental mapping I am having with the memory system currently. I 
> have some more experience with high performance programs in C++ 
> and appreciate the transparency of the memory management.

Yup, I understand that feeling fully.

If you are like me, then you will be expecting D to be similar to 
C++ in more ways than it is, and encounters with the differences 
will be frustrating at first.

The GC is something else to get used to, and I may never get used 
to it after years of mentally mapping out where and how memory is 
allocated and deallocated. I just don't trust that a GC will do 
the job properly and I have this horrible feeling that it will 
waste vast amounts of memory like java apps seem to do, and that 
it will miss deallocations for certain edge cases, like a union 
with a pointer or class reference in it. At this point, all I 
have is faith that it is doing the job properly, but that's not 
how I operate. I need to know exactly what it is doing and how to 
detect when it is not doing what I think it should be doing. This 
is an area I have not tackled yet but intend to.

--rt