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Re: About self-referential object
From: |
Xue Fuqiao |
Subject: |
Re: About self-referential object |
Date: |
Sat, 5 Jan 2013 09:26:02 +0800 |
On Fri, 4 Jan 2013 16:55:56 -0800
"Drew Adams" <drew.adams@oracle.com> wrote:
> Let's assume first that it tries to print the infinite object without any
> abbreviation. When it starts printing the value of `foo' it is at level 0
> (top
> level). When it tries to print the car of that cons, it needs to print the
> value of `foo' again, this time at printing level 1: `((foo))'. When it tries
> to print that third `foo' it is at level 2, and so on. Think of the printing
> "levels" here as recursive calls to a printing function.
>
> To abbreviate, it prints just (#0), meaning a single cons cell with, as its
> car,
> the same cons cell, i.e., the object that the printer started out to print.
Ah, I see, thanks.
--
Best regards, Xue Fuqiao.
http://www.emacswiki.org/emacs/XueFuqiao