non-copy slices

Ethan Furman ethan at stoneleaf.us
Thu Nov 19 19:08:36 EST 2009


Themis Bourdenas wrote:
> On Thu, Nov 19, 2009 at 2:44 PM, Ethan Furman <ethan at stoneleaf.us 
> <mailto:ethan at stoneleaf.us>> wrote:
> 
>     So "shallow copy" == "new label created for existing object".
> 
>     So is your desired behavior to write back to the original list if your
>     sub-list is modified?  In other words, you are creating a window onto an
>     existing list?  If not, what would happen when a sublist element was
>     modified (or deleted, or appended, or ...)?
> 
>     ~Ethan~
> 
> Yes a window / view on the existing list describes it best. So every 
> modification you make in this view is actually modifying the original 
> list accordingly. Blist that was suggested in a previous email in the 
> thread seems lightweight but it does create a new list when a 
> modification is made. In any case, I've already implemented the object 
> myself and I can post it if you care to have a look, but I was just 
> wondering if there was already something in the standard library.
> 
> Themis

Unfortunately, I am not very familiar with the stdlib yet (gotta buy 
that book!).  I'm going to guess 'No' since nobody has chimed in with a 
'Yes', though.

I'd love to see what you have for that.  Does in support a stepped 
window, or only contiguous sequences?  The one I put together this 
afternoon only does contiguous sequences, as I had no use cases to 
decide how assignments of multiple items should be handled, and not a 
lot of time to implement something generic -- so, to answer John's 
question from a completely different thread, yes I do enjoy working on 
small projects even if IAGNI.  :)

Cheers!

~Ethan~



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