Revised RFC on range design for D2

[Bill Baxter]

On Sat, Oct 4, 2008 at 11:57 AM, KennyTM~ <kennytm at gmail.com> wrote:
> Bill Baxter wrote:
>>
>> On Fri, Oct 3, 2008 at 11:02 PM, Andrei Alexandrescu
>> <SeeWebsiteForEmail at erdani.org> wrote:
>>>
>>> Sergey Gromov wrote:
>>>>
>>>> Thu, 02 Oct 2008 15:03:42 -0500,
>>>> Andrei Alexandrescu wrote:
>>>>>
>>>>> Yah, overloaded ops are due for an overhaul. I'm almost afraid to
>>>>> ask...
>>>>> any ideas? :o)
>>>>>
>>>>> One goal is to fix opIndexAssign and make it work similar to the way it
>>>>> works in arrays, e.g. a[b] += c. Indexing into hash tables is a good
>>>>> test
>>>>> bed.
>>>>
>>>> What's wrong with a.opIndexAssign(b, a.opIndex(b) + c)?
>>>
>>> One problem is that for a hashtable that does not have b yet, opIndex
>>> will
>>> throw an exception.
>>
>> I don't see why you expect   a[b] += c to work on a key for which a[b]
>> is undefined.  If it's undefined how can you increment it?
>
> Actually I did use it once to count things, so I could just use a[b]++
> instead of the clumsy if(b in a){a[b]++;}else{a[b]=1;}.

But D hashmaps don't work like that.
I guess std::map in C++ does behave like that, so that could explain
why Andrei would expect that behavior from a map data structure.

--bb