This is an `Introduction to Programming in Emacs Lisp', for people who
are not programmers.
-Edition 3.00, 2006 Oct 31
+Edition 3.01, 2006 Oct 31
Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1997, 2001, 2002,
2003, 2004, 2005, 2006 Free Software Foundation, Inc.
this GNU Manual, like GNU software. Copies published by the Free
Software Foundation raise funds for GNU development."
+\1f
+File: eintr, Node: See variable current value, Next: defvar and asterisk, Prev: defvar, Up: defvar
+
+Seeing the Current Value of a Variable
+--------------------------------------
+
+You can see the current value of a variable, any variable, by using the
+`describe-variable' function, which is usually invoked by typing `C-h
+v'. If you type `C-h v' and then `kill-ring' (followed by <RET>) when
+prompted, you will see what is in your current kill ring--this may be
+quite a lot! Conversely, if you have been doing nothing this Emacs
+session except read this document, you may have nothing in it. Also,
+you will see the documentation for `kill-ring':
+
+ Documentation:
+ List of killed text sequences.
+ Since the kill ring is supposed to interact nicely with cut-and-paste
+ facilities offered by window systems, use of this variable should
+ interact nicely with `interprogram-cut-function' and
+ `interprogram-paste-function'. The functions `kill-new',
+ `kill-append', and `current-kill' are supposed to implement this
+ interaction; you may want to use them instead of manipulating the kill
+ ring directly.
+
+The kill ring is defined by a `defvar' in the following way:
+
+ (defvar kill-ring nil
+ "List of killed text sequences.
+ ...")
+
+In this variable definition, the variable is given an initial value of
+`nil', which makes sense, since if you have saved nothing, you want
+nothing back if you give a `yank' command. The documentation string is
+written just like the documentation string of a `defun'. As with the
+documentation string of the `defun', the first line of the
+documentation should be a complete sentence, since some commands, like
+`apropos', print only the first line of documentation. Succeeding
+lines should not be indented; otherwise they look odd when you use `C-h
+v' (`describe-variable').
+
\1f
File: eintr, Node: defvar and asterisk, Prev: See variable current value, Up: defvar
names can and often should be longer than 12 characters; this length
works well in a typical 80 column wide window.)
-`:eval' was a new feature in GNU Emacs version 21. It says to evaluate
-the following form and use the result as a string to display. In this
-case, the expression displays the first component of the full system
-name. The end of the first component is a `.' (`period'), so I use the
-`string-match' function to tell me the length of the first component.
-The substring from the zeroth character to that length is the name of
-the machine.
+`:eval' says to evaluate the following form and use the result as a
+string to display. In this case, the expression displays the first
+component of the full system name. The end of the first component is a
+`.' (`period'), so I use the `string-match' function to tell me the
+length of the first component. The substring from the zeroth character
+to that length is the name of the machine.
This is the expression:
* yank-pop::
* ring file::
-\1f
-File: eintr, Node: current-kill, Next: yank, Prev: Kill Ring, Up: Kill Ring
-
-B.1 The `current-kill' Function
-===============================
-
-The `current-kill' function changes the element in the kill ring to
-which `kill-ring-yank-pointer' points. (Also, the `kill-new' function
-sets `kill-ring-yank-pointer' to point to the latest element of the the
-kill ring.)
-
-The `current-kill' function is used by `yank' and by `yank-pop'. Here
-is the code for `current-kill':
-
- (defun current-kill (n &optional do-not-move)
- "Rotate the yanking point by N places, and then return that kill.
- If N is zero, `interprogram-paste-function' is set, and calling it
- returns a string, then that string is added to the front of the
- kill ring and returned as the latest kill.
- If optional arg DO-NOT-MOVE is non-nil, then don't actually move the
- yanking point; just return the Nth kill forward."
- (let ((interprogram-paste (and (= n 0)
- interprogram-paste-function
- (funcall interprogram-paste-function))))
- (if interprogram-paste
- (progn
- ;; Disable the interprogram cut function when we add the new
- ;; text to the kill ring, so Emacs doesn't try to own the
- ;; selection, with identical text.
- (let ((interprogram-cut-function nil))
- (kill-new interprogram-paste))
- interprogram-paste)
- (or kill-ring (error "Kill ring is empty"))
- (let ((ARGth-kill-element
- (nthcdr (mod (- n (length kill-ring-yank-pointer))
- (length kill-ring))
- kill-ring)))
- (or do-not-move
- (setq kill-ring-yank-pointer ARGth-kill-element))
- (car ARGth-kill-element)))))
-
-In addition, the `kill-new' function sets `kill-ring-yank-pointer' to
-the latest element of the the kill ring. And indirectly so does
-`kill-append', since it calls `kill-new'. In addition, `kill-region'
-and `kill-line' call the `kill-new' function.
-
-Here is the line in `kill-new', which is explained in *Note The
-`kill-new' function: kill-new function.
-
- (setq kill-ring-yank-pointer kill-ring)
-
-* Menu:
-
-* Understanding current-kill::
-
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