associative arrays

Steven Schveighoffer schveiguy at
Mon Jan 9 10:52:18 PST 2012

On Mon, 09 Jan 2012 13:35:26 -0500, Andrej Mitrovic  
<andrej.mitrovich at> wrote:

> On 1/9/12, Steven Schveighoffer <schveiguy at> wrote:
>> BTW, dcollections' HashMap, HashSet, and HashMultiset do guarantee that
>> adding elements does not invalidated cursors (dcollections' safe version
>> of pointers) as long as you use the default Hash implementation.   
>> However,
>> I just noticed this is not stated anywhere in the docs (will fix).
> Funny, I was looking at the docs a few days ago and it said "Adding an
> element can invalidate cursors depending on the implementation.", so I
> just assumed it did invalidate the cursors.

Yeah, I could have sworn I stated somewhere that the current  
implementation doesn't invalidate cursors, but apparently it's not  
stated.  I think the docs need a lot of TLC before the first release.   
Some day when I have time...

To clarify what I plan to do, the add doc will say something like "adding  
an element can invalidate cursors depending on the implementation, however  
the default implementation guarantees not to invalidate them."  I don't  
want to specifically disallow implementations which do invalidate  
(dcollections' implementations are pluggable so anyone can replace the  

> I do think those are dcollections v1 docs though. Anyway glad to hear
> from you about this.

The D2 docs are somewhat leftover from D1 version.  However, I do remember  
when implementing the hash code that it purposely does not invalidate  
cursors on a rehash.  Ranges can be invalidated, however.  Given the  
implementation, it's actually faster *not* to invalidate them when  
rehashing because I just relink all the link-list nodes instead of  
reallocating them.


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