foreach for string[string]AA

[Minty Fresh via Digitalmars-d-learn]

On Tuesday, 28 February 2017 at 18:16:45 UTC, Anton Pastukhov 
wrote:
> On Tuesday, 28 February 2017 at 17:16:43 UTC, Daniel Kozák 
> wrote:
>> V Tue, 28 Feb 2017 15:15:00 +0000
>> Anton Pastukhov via Digitalmars-d-learn
>> <digitalmars-d-learn at puremagic.com> napsáno:
>>
>>> I can't see the logic in AA foreach order. Consider this code:
>>> ...
>>> Output:
>>> three
>>> two
>>> one
>>> four
>>> 
>>> I was sure output should be
>>> one
>>> two
>>> three
>>> four
>>
>> https://forum.dlang.org/post/xbanhtkvrizyqjcibsck@forum.dlang.org
>
> Thank you for the link, it was informative reading. It's a pity 
> that still there is no ordered AA at least as a library type.

Ordered AA isn't that common a use case, and it's not without 
overhead. You essentially need to store an array of keys that 
define iteration order, which requires extra memory allocations 
(and, depending on implementation, may slow down iteration as 
well).

I come from a Ruby background, so I have found key order useful 
in the past, but in most cases I probably could've gotten by just 
fine with an array or set of element pairs.

Introduction of a more convenient tuple type into D might make 
something like this easier.