From: Robert Klemme <shortcutter@...>
Date: 2008-03-11T23:18:55+09:00
Subject: Re: Ordered Collection

2008/3/11, Eric Mahurin <eric.mahurin@gmail.com>:

>  Ruby, unfortunately is really lacking on this front.

Did you see my references to libs in RAA?  Do they lack something that you need?

>  When doing geometric
>  stuff, I find every ounce of C++ STL useful.  An STL-like ruby lib would be
>  useful.  External iterators are also very important.  Ruby's normal internal
>  iterators (what others might call visitors) don't have the same flexibility
>  (caller can go forward/backward/read/write/erase/insert at will).

That's an interesting point you make.  I haven't noticed the lack of
external iterators (there *is* in fact an implementation, albeit with
limited functionality) so far.  For me the most pressing disadvantage
of #each and family so far was that you cannot iterate several
collections at the same time with this.  For random access you can use
an Array with index.  And for Arrays it would be fairly easy to write
a thin wrapper around such an index which will allow all the movements
and operations you are wanting.

For deletions there are also methods that will do the job with O(n).
Alternatively, when using Arrays, you can use #splice! and []=.

Can you leak a bit more information about the scenarios where you need
more / different behavior?

Kind regards

robert

-- 
use.inject do |as, often| as.you_can - without end