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Re: "push" creating circular objects
From: |
Pascal J. Bourguignon |
Subject: |
Re: "push" creating circular objects |
Date: |
Sat, 23 Aug 2008 14:17:47 +0200 |
User-agent: |
Gnus/5.1008 (Gnus v5.10.8) Emacs/22.2 (gnu/linux) |
Charles Sebold <csebold@gmail.com> writes:
> On 21 Aug 2008, John Paul Wallington wrote:
>
>> I'm not certain what's going on. Are you sure that representation
>> means circular structure? Or is it merely labelling the object "ul"
>> for future reference then referring to it? (See (elisp)Circular
>> Objects.)
>
> I am likely confused. Is this not the same thing?
>
> Oh. I guess it isn't. This is one of the insights I needed, I think.
>
>> Also, how about consing up the strings with (string ?u ?l) or somesuch
>> to avoid 'em being treated as the same?
>
> I'll give that a try... yeah, that fixed it. I'm surprised I have to do
> this, though. Why are they being treated as the same?
>
> Knowing this, I replaced (string ?u ?l) with (copy-sequence "ul") and so
> forth, and got the same result.
>
> Thanks very much for this. But I'm surprised I have to do it.
The syntax ##/#= is used to be able to distinguish these cases:
+-----------------------+ +-----------------------+
| (#1="ul" #1#) | | ("ul" "ul") |
| | | |
| +---+---+ +---+---+ | | +---+---+ +---+---+ |
| | * | * |-->| * |nil| | | | * | * |-->| * |nil| |
| +---+---+ +---+---+ | | +---+---+ +---+---+ |
| | | | | | | |
| | +--------+ | | v v |
| | | | | +------+ +------+ |
| v v | | | "ul" | | "ul" | |
| +------+ | | +------+ +------+ |
| | "ul" | | +-----------------------+
| +------+ |
+-----------------------+
--
__Pascal Bourguignon__ http://www.informatimago.com/
"I have challenged the entire quality assurance team to a Bat-Leth
contest. They will not concern us again."
- Re: "push" creating circular objects, (continued)
- Re: "push" creating circular objects, weber, 2008/08/20
- Re: "push" creating circular objects, weber, 2008/08/20
- Re: "push" creating circular objects, Charles Sebold, 2008/08/21
- Re: "push" creating circular objects, xraysmalevich, 2008/08/21
- Re: "push" creating circular objects, Charles Sebold, 2008/08/21
- Re: "push" creating circular objects, Pascal J. Bourguignon, 2008/08/21
- Re: "push" creating circular objects, Charles Sebold, 2008/08/21
Re: "push" creating circular objects, John Paul Wallington, 2008/08/21