From: MenTaLguY <mental@...>
Date: 2005-12-10T14:01:43+09:00
Subject: Re: next, retry, break?

--=-dGviWF61d6iUg6du6Iv8
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable

On Sat, 2005-12-10 at 11:29 +0900, Yukihiro Matsumoto wrote:

> If you want "redo" to work, you have to initialize your @current_grob
> at the beginning of the iterating method.  Since many expect "each" to
> enumerate all the values in the collection, initializing at the top is
> a good thing in general.

Thanks...

This is for a stream class, so it would be a "consuming" each like
IO#each.  In that case not initializing is okay (it should behave just
like IO#each does).  The problem was that I was not advancing the stream
pointer until after the yield -- solved with 'ensure'.

Just to be sure I understand correctly now:

 redo: jumps to the start of the block

 next: jumps to the end of the block
       using the given value (or nil)
       as the block's result

 retry: unwinds the stack to the call
        site of the "closest" yielding
        method, calling it again with
        the same arguments

 break: unwinds the stack to the call
        site of the "closest" yielding
        method, using the given value
        (or nil) as the method's result

Is that right?

If so, what if I want retry or break to unwind further (e.g. because I
am implementing one iterator in terms of another)?

-mental

--=-dGviWF61d6iUg6du6Iv8
Content-Type: application/pgp-signature; name=signature.asc
Content-Description: This is a digitally signed message part

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.1 (GNU/Linux)

iD8DBQBDmlwNcUNIGiXCc4MRAlpaAJ4iU8eC25mk9sbu8JQEhDoATUb31wCeKYot
AQu7Iw7BHZ6o4jYv4YcR19M=
=/KIE
-----END PGP SIGNATURE-----

--=-dGviWF61d6iUg6du6Iv8--