Re: [Ocaml-reins-devel] possible bugs in iterators

[Michael F. <fu...@cs...>]

On Mon, 5 Nov 2007, Ashish Agarwal wrote:

> Hi. Please consider following code:
[snip]

> which prints out
>  1 2 3 4

Oops!

> What is the semantics of Traverse_While? I was expecting the iterator to
> stop at 3.

Indeed, this is the intended semantics.

> The iterator seems to go one element extra. Trying with m = 0 prints the 
> value 1 even though the predicate given to Traverse_While is never 
> satisfied.
>
> Also, leave m = 3, and remove 2 from the list. Then we get Exception:
> Failure "get_value".
> Alternatively, leave the list as shown above and set m = 7. I was expecting
> same error again, but there is no Failure this time.

Hmm... sorry about that.  I must admit I haven't actually tested the While 
iterator as much as I should.  I wasn't sure if I liked the way the cursor 
interface was setup, so I've actually been planning on revisiting this 
entire part of the library.  I'm currently insanely busy working on a 
paper, but I'll look at this next week when I should (finally) have some 
time to get back to hacking on reins.

Thanks for your email.
-m

P.S.  If you have any suggestions about how to improve the way the 
iterators or cursors are presented, I would love to hear them.  I have 
only 1 or 2 usage scenerios in my head and I'm not sure how other people 
might like to use these.