Multi-associative array

[Andrei Alexandrescu]

On 2/22/14, 11:10 PM, Etienne Cimon wrote:
> On 2014-02-23 01:27, H. S. Teoh wrote:
>> You can just use a struct or tuple as the AA key to achieve the same
>> thing.
>
> I thought of that but it's not immediately obvious how I could achieve
> sorting or filtering by a certain field
>
> e.g.
> auto sorted = aa.sort!(Key.y => { a < b })
> auto filtered = aa.filter! ....
>
> foreach(x, y, z ; aa){
> ....
> }
>
> I don't see a very simple way of doing this right now. I'm sure someone
> thought of a library for this?

The way multiple binary tree (or rb-tree) indexes are achieved is by 
storing multiple pointers with the same value. That way really multiple 
threes are threaded using the same value nodes.

There's no trivial way to do this. It would be very valuable to 
generalize RBTree to accept multiple predicates and build such multiple 
indexes.


Andrei