[Feature Request] Adding to D lang "set" built-in

[Era Scarecrow]

On Monday, 7 May 2012 at 05:54:04 UTC, Jonathan M Davis wrote:
> On Monday, May 07, 2012 06:49:00 Russel Winder wrote:
>> Any language with which the programmer has to develop their  
>> own set implementation is sadly lacking.
>> 
>> It is true that set can be implemented using a map, but this  
>> should be seen as implementation detail, not as programmer 
>> level tool. It indicates that set should exist where set does. 
>> So for C++ it  is in the standard library, for Python it is a 
>> built-in (*).
>> 
>> The conclusion for D is straightforward. Which issue to I go  
>> to to vote?
>
> We have RedBlackTree, so we have a set already. What we don't  
> have is a HashSet. However, once the custom allocator stuff has 
> been  sorted out, I'd fully expect to have one in std.container 
> along with a variety  of other container types which we really 
> should have but don't.

  Been thinking about this a little. With arrays, fixed arrays and 
associative arrays being built in, you don't need set to be built 
in. First it's already hash-map like so it's going to be O(1), 
and the data being kinda useless can either be a byte, and int 
(offset to an array perhaps), or to itself.

  It has the added benefit of being a sparse array when asked of 
it. So aside from a slight loss in memory space which is only 
going to be critical in embedded systems. The only thing the 
builtins don't offer is a way to automatically sort the data, 
which the libraries and RedBlackTree's do quite well so far as I 
can see.