What's the deal with __buck?

[Bill Baxter]

On Fri, Jan 30, 2009 at 5:58 AM, Don <nospam at nospam.com> wrote:
> Jarrett Billingsley wrote:
>>
>> On Thu, Jan 29, 2009 at 12:48 PM, Andrei Alexandrescu
>> <SeeWebsiteForEmail at erdani.org> wrote:
>>>
>>> BCS wrote:
>>>>
>>>> Hello Bill,
>>>>>
>>>>> I guess what's required is the ability to define the __dollar in the
>>>>> scope of a class/struct/template.
>>>>
>>>> I think that is the correct solution.
>>>
>>> Ok, thanks to all. So __dollar is looked up at module scope for anything
>>> that's not a built-in array.
>>>
>>> I thought some more about it and I think there's no need for __dollar.
>>> It's enough that:
>>>
>>> a) In slice expressions and index expressions with one argument, $
>>> expands
>>> to value.length, where value is the object being indexed/sliced (if an
>>> unnamed temporary, the value is of course only evaluated once)
>>>
>>> b) In index expressions with multiple arguments, $ expand to
>>> value.length(i), where i is the zero-based argument position.
>>>
>>> This is exactly enough what's needed to make it all work. Infinite
>>> ranges may define a symbolic infinite length and overload slicing on it.
>>
>> Sounds good.  Question - since length will work for multiple indices,
>> will it ever be possible to have .. multiple slices?
>>
>> a[x1 .. x2, y1 .. y2] = b;
>
> You can do that with opIndex already.

Can you?  How?  As far as I know any index expression with more than
one  ..  in it automatically generates a compiler error.

--bb