comp.lang.ruby

Simon Strandgaard

4/28/2005 4:31:00 PM

On 4/28/05, Eric Mahurin <eric_mahurin@yahoo.com> wrote:
> --- Simon Strandgaard <neoneye@gmail.com> wrote:
> > I have made a lib containing some external iterators, see:
> > http://aeditor.rubyforge.org...
> >
> > download it here:
> > http://rubyforge.org/frs/download.php/704/iterat...
>
> Thanks Simon. I just looked through what you have. You gave
> me a few ideas. But, here are a few things I don't like:
>
> * for efficiency I would like the ability to read/write
> multiple elements at a time. I want the API to have a superset
> of the features in IO if possible.

True, I didn't made mine for speed.


> * instead of calling has_next? I'm just having next return nil
> or an empty string/array (for getting N elements). If the
> collection can have nil elements, you'll have to ask for N
> elements (could be 1) so that you get an empty array at the
> end.

What if you are iterating through an array that coincidentially
contains a nil.. like this [42, nil, 42] ?


> * no standard insert/delete operations. I don't need them now,
> but they might be useful to others.

Yeah, I don't have neither insert nor delete.
I didn't needed it when I made the lib. I though about it,
but couldn't decide how to approach this problem.


> * like the C++ iterator, yours standardizes on
> allowing/creating/comparing multiple iterators on the same data
> structure. I don't want to do this because many sequential
> data structures can't handle this. The primary example would
> be an IO (especially a non-file) which only allows you to
> read/write at one location at a time. Another would be a text
> editor buffer where you can only insert/delete at the cursor
> position. Instead of allowing multiple iterators for a data
> structure, you'll be able to get and set the position where
> "position" is an object that you might be able to compare
> and/or do arithmetic on (depends on the data structure).

This sounds interesting. I would be interesting at looking
at how you would approach this.


> I think I'll call the class I'm doing "Cursor" because it most
> resembles what you can do at the cursor in a text editor and
> I've also seen the term "cursor" used for external iterator.
>
> I might take some of the ideas in your Iterator classes also
> (some from C++ STL iterator it looks like), if you don't mind.

Feel free to use all of it as you like.
Is your project on rubyforge ?

--
Simon Strandgaard