From 82ba818ff456bcd6d56a06226e3f27e98fbb55c3 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Thu, 14 Aug 2025 22:58:58 -0500 Subject: removing all downloaded devdocs files --- devdocs/elisp/circular-objects.html | 25 ------------------------- 1 file changed, 25 deletions(-) delete mode 100644 devdocs/elisp/circular-objects.html (limited to 'devdocs/elisp/circular-objects.html') diff --git a/devdocs/elisp/circular-objects.html b/devdocs/elisp/circular-objects.html deleted file mode 100644 index 797d97b1..00000000 --- a/devdocs/elisp/circular-objects.html +++ /dev/null @@ -1,25 +0,0 @@ -

Read Syntax for Circular Objects

To represent shared or circular structures within a complex of Lisp objects, you can use the reader constructs ‘#n=’ and ‘#n#’.

Use #n= before an object to label it for later reference; subsequently, you can use #n# to refer the same object in another place. Here, n is some integer. For example, here is how to make a list in which the first element recurs as the third element: 

(#1=(a) b #1#)
-
-

This differs from ordinary syntax such as this 

((a) b (a))
-
-

which would result in a list whose first and third elements look alike but are not the same Lisp object. This shows the difference: 

(prog1 nil
-  (setq x '(#1=(a) b #1#)))
-(eq (nth 0 x) (nth 2 x))
-     ⇒ t
-(setq x '((a) b (a)))
-(eq (nth 0 x) (nth 2 x))
-     ⇒ nil
-
-

You can also use the same syntax to make a circular structure, which appears as an element within itself. Here is an example: 

#1=(a #1#)
-
-

This makes a list whose second element is the list itself. Here’s how you can see that it really works: 

(prog1 nil
-  (setq x '#1=(a #1#)))
-(eq x (cadr x))
-     ⇒ t
-
-

The Lisp printer can produce this syntax to record circular and shared structure in a Lisp object, if you bind the variable print-circle to a non-nil value. See Output Variables.

-

- Copyright © 1990-1996, 1998-2022 Free Software Foundation, Inc.
Licensed under the GNU GPL license.
- https://www.gnu.org/software/emacs/manual/html_node/elisp/Circular-Objects.html -

-
-- cgit v1.2.3