Frustrations with const

[H. S. Teoh]

On Fri, Mar 09, 2012 at 11:24:46AM +0100, Timon Gehr wrote:
> On 03/08/2012 09:06 PM, H. S. Teoh wrote:
> >On Thu, Mar 08, 2012 at 02:50:50PM -0500, Steven Schveighoffer wrote:
[...]
> >>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.
> 
> Probably it does not. What is the type of the "slots" hashtable?

Here are the relevant declarations:

    struct Slot
    {
        Slot   *next;
        hash_t  hash;
        Key     key;
        Value   value;

        this(hash_t h, Key k, Value v)
        {
            hash = h;
            key = k;
            value = v;
        }
    }

    struct Impl
    {
        Slot*[]  slots;
        size_t   nodes;

        // Prevent extra allocations for very small AA's.
        Slot*[4] binit;
    }


[...]
> >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.
[...]
> This is a general issue with how auto infers types. It would often be
> useful to get the head-mutable type out of the type deduction instead
> of the actual type.

Yeah, that would be very useful.


T

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