Standalone AA implementation ready for review (Was: Re: Replacing AA's in druntime)

[Dmitry Olshansky]

On 15.03.2012 21:22, H. S. Teoh wrote:
> On Thu, Mar 15, 2012 at 05:02:06PM +0100, Don Clugston wrote:
>> On 15/03/12 00:16, H. S. Teoh wrote:
> [...]
>> This is good, and very, very important. Do *not* make any attempt at
>> compiler integration until it is *completely* ready.
>>
>> This includes AA literals. They need to be accepted somehow. The
>> compiler will give you syntax sugar and *nothing* more.
>
> How does the compiler currently work with AA literals? I see two
> functions in aaA.d for constructing AA's from literals. Which one is the
> one actually being used?
>
>
>> One possibility might be to accept a pair of array literals,
>> representing keys and values.
>
> OK. This shouldn't be hard to do. I'll take a stab at it.
>
>
>> Possibly it should call a CTFE function to convert them into some
>> other form?
>
> This is one major area that I forgot to mention, and that is, making AA
> literals work at compile-time. Currently things like this don't work:
>
> 	enum myAA = ["abc":123, "def":456];
>
> I'd like to make that work. That would require compile-time construction
> of the AA and storing it in some form that the compiler can put into the
> object file.

What's wrong with AA structure itself, it's link-pointer based?
At any rate, I stored complex structs as immutable, though links were 
index-based.

I'm thinking of something along the lines of using mixins
> to generate explicit instances of Slot structs, so the above would
> translate to something like:
>
> 	Impl __myAA_literal_impl = Impl(__myAA_literal_slots[0..$], 2);
> 	Slot[4] __myAA_literal_slots = [
> 		// The exact order in here will depend on precise hash
> 		// values, which will need to be somehow computed by
> 		// CTFE. Is that even remotely possible right now??
> 		null,
> 		&__myAA_literal_slot1,
> 		null,
> 		&__myAA_literal_slot2
> 	];
> 	Slot __myAA_literal_slot1 = Slot(null, /*hash value*/, "abc", 123);
> 	Slot __myAA_literal_slot2 = Slot(null, /*hash value*/, "def", 456);
> 	enum myAA = AssociativeArray!(string,int)(&__myAA_literal_impl);
>
> Would something like this be workable? Is it even possible to compute
> the necessary hashes at compile-time?
>
>
> T
>


-- 
Dmitry Olshansky