Frustrations with const

[Steven Schveighoffer]

On Thu, 08 Mar 2012 15:06:19 -0500, H. S. Teoh <hsteoh at quickfur.ath.cx>  
wrote:

> On Thu, Mar 08, 2012 at 02:50:50PM -0500, Steven Schveighoffer wrote:
>> On Thu, 08 Mar 2012 14:49:12 -0500, H. S. Teoh
>> <hsteoh at quickfur.ath.cx> wrote:
>>
>> >On Thu, Mar 08, 2012 at 08:22:05PM +0100, Timon Gehr wrote:
> [...]
>> >>inout(Slot)* findSlot(Key key) inout { ... }
>> >
>> >Ahhh. Thanks!
>> >
>> >But that still doesn't solve the problem:
>> >
>> >	inout(Slot)* findSlot(Key key) inout {
>> >		auto slot = slots[hash(key)];
>>
>> What is type slot, and how is it constructed?  This snippit isn't
>> enough to provide help.
> [...]
>
> Slot is a struct, and slots is Slots*[].  But anyway, I found the
> problem.  I needed to explicitly declare slot as:
>
> 	inout(Slot)* slot = ...
>
> because for whatever reason, auto turns it into inout(Slot*) which
> cannot be modified.

I was wondering, because your error message identified it as inout(Slot)*,  
which should be modifiable...

> I think inout is one of those things that really needs more thorough
> treatment for newbies, because coming from a C/C++ background I had no
> idea what was wrong. Now that I get it, it makes so much more sense.

It's kind of a new concept to D even (since 2.056).  It's not completely  
fleshed out yet, Timon, Kenji, and Stuart have some great ideas on making  
it better.

This article might help: http://drdobbs.com/blogs/cpp/231902461

I plan to write a const/inout article at some point.

-Steve