@comment %**end of header
-@set edition-number 3.05
-@set update-date 5 November 2006
+@set edition-number 3.06
+@set update-date 6 November 2006
@ignore
## Summary of shell commands to create various output formats:
# makeinfo --no-split --paragraph-indent=0 --verbose emacs-lisp-intro.texi
makeinfo --paragraph-indent=0 --verbose emacs-lisp-intro.texi
- ## ;; (progn (when (bufferp (get-buffer "*info*")) (kill-buffer "*info*")) (info "/u/intro/emacs-lisp-intro.info"))
+ ## ;; (progn (when (bufferp (get-buffer "*info*")) (kill-buffer "*info*")) (info "../info/eintr"))
## DVI output
texi2dvi emacs-lisp-intro.texi
@key{RET}}. (On some keyboards, the @key{META} key is labelled
@key{ALT}.)
-@c !!! 22.1.100 tags table location in this paragraph
+@c !!! 22.1.1 tags table location in this paragraph
@cindex TAGS table, specifying
@findex find-tags
Depending on how the initial default values of your copy of Emacs are
if it has already been created for you, will be in a subdirectory of
the @file{/usr/local/share/emacs/} directory; thus you would use the
@code{M-x visit-tags-table} command and specify a pathname such as
-@file{/usr/local/share/emacs/22.1.100/lisp/TAGS}. If the tags table
+@file{/usr/local/share/emacs/22.1.1/lisp/TAGS}. If the tags table
has not already been created, you will have to create it yourself. It
will in a file such as @file{/usr/local/src/emacs/src/TAGS}.
@comment node-name, next, previous, up
@chapter Yanking Text Back
@findex yank
-@findex rotate-yank-pointer
@cindex Text retrieval
@cindex Retrieving text
@cindex Pasting text
is easier to understand.)
To begin to understand how @code{yank} and @code{yank-pop} work, it is
-first necessary to look at the @code{kill-ring-yank-pointer} variable
-and the @code{rotate-yank-pointer} function.
+first necessary to look at the @code{kill-ring-yank-pointer} variable.
@node kill-ring-yank-pointer, yank nthcdr Exercises, Kill Ring Overview, Yanking
@comment node-name, next, previous, up
place your cursor after the following expression and type @kbd{C-x
C-e} (@code{eval-last-sexp}).
-@c !!! 22.1.100 lisp sources location here
+@c !!! 22.1.1 lisp sources location here
@smallexample
(lengths-list-file
- "/usr/local/share/emacs/22.1.100/lisp/emacs-lisp/debug.el")
+ "/usr/local/share/emacs/22.1.1/lisp/emacs-lisp/debug.el")
@end smallexample
@noindent
(You may need to change the pathname of the file; the one here is for
-GNU Emacs version 22.1.100. To change the expression, copy it to
+GNU Emacs version 22.1.1. To change the expression, copy it to
the @file{*scratch*} buffer and edit it.
@need 1200
name to the absolute, long, path name form. The function employs the
name of the directory in which the function is called.
-@c !!! 22.1.100 lisp sources location here
+@c !!! 22.1.1 lisp sources location here
@need 1500
Thus, if @code{expand-file-name} is called on @code{debug.el} when
Emacs is visiting the
-@file{/usr/local/share/emacs/22.1.100/lisp/emacs-lisp/} directory,
+@file{/usr/local/share/emacs/22.1.1/lisp/emacs-lisp/} directory,
@smallexample
debug.el
@noindent
becomes
-@c !!! 22.1.100 lisp sources location here
+@c !!! 22.1.1 lisp sources location here
@smallexample
-/usr/local/share/emacs/22.1.100/lisp/emacs-lisp/debug.el
+/usr/local/share/emacs/22.1.1/lisp/emacs-lisp/debug.el
@end smallexample
The only other new element of this function definition is the as yet
the @file{*scratch*} buffer, edit them, and then evaluate them.
The results are shown after the @samp{@result{}}. (These results are
-for files from Emacs Version 22.1.100; files from other versions of
+for files from Emacs Version 22.1.1; files from other versions of
Emacs may produce different results.)
-@c !!! 22.1.100 lisp sources location here
+@c !!! 22.1.1 lisp sources location here
@smallexample
@group
-(cd "/usr/local/share/emacs/22.1.100/")
+(cd "/usr/local/share/emacs/22.1.1/")
(lengths-list-file "./lisp/macros.el")
@result{} (283 263 480 90)
For example, the first @samp{.el} file in the @file{lisp/} directory
is @file{abbrev.el}. Its name is
-@file{/usr/local/share/emacs/22.1.100/lisp/abbrev.el} and it is not a
+@file{/usr/local/share/emacs/22.1.1/lisp/abbrev.el} and it is not a
directory or a symbolic link.
@need 1000
(directory-files "/usr/local/src/emacs/lisp/" t "\\.el$")
(shell-command "find /usr/local/src/emacs/lisp/ -name '*.el'")
-(directory-files "/usr/local/share/emacs/22.1.100/lisp/" t "\\.el$")
-(shell-command "find /usr/local/share/emacs/22.1.100/lisp/ -name '*.el'")
+(directory-files "/usr/local/share/emacs/22.1.1/lisp/" t "\\.el$")
+(shell-command "find /usr/local/share/emacs/22.1.1/lisp/ -name '*.el'")
@end ignore
-@c /usr/local/share/emacs/22.1.100/lisp/
+@c /usr/local/share/emacs/22.1.1/lisp/
@need 800
Here is the function:
;; Although the function will be used non-interactively,
;; it will be easier to test if we make it interactive.
;; The directory will have a name such as
- ;; "/usr/local/share/emacs/22.1.100/lisp/"
+ ;; "/usr/local/share/emacs/22.1.1/lisp/"
(interactive "DDirectory name: ")
@end group
@group
@end smallexample
@c (files-in-below-directory "/usr/local/src/emacs/lisp/")
-@c (files-in-below-directory "/usr/local/share/emacs/22.1.100/lisp/")
+@c (files-in-below-directory "/usr/local/share/emacs/22.1.1/lisp/")
The @code{files-in-below-directory} @code{directory-files} function
takes one argument, the name of a directory.
@c (length (files-in-below-directory "/usr/local/src/emacs/lisp/"))
-@c !!! 22.1.100 lisp sources location here
+@c !!! 22.1.1 lisp sources location here
@smallexample
@group
(length
- (files-in-below-directory "/usr/local/share/emacs/22.1.100/lisp/"))
+ (files-in-below-directory "/usr/local/share/emacs/22.1.1/lisp/"))
@end group
@end smallexample
@smallexample
@group
(sort
- (files-in-below-directory "/usr/local/share/emacs/22.1.100/lisp/")
+ (files-in-below-directory "/usr/local/share/emacs/22.1.1/lisp/")
'string-lessp)
@end group
@end smallexample
(In a read-only buffer, such as the @file{*info*} buffer, the kill
command, @kbd{C-k} (@code{kill-line}), will not remove the text,
merely copy it to the kill ring. However, your machine may beep at
-you. (@code{kill-line} calls @code{kill-region}.) Alternatively, for
-silence, you may copy the region of each line with the @kbd{M-w}
-(@code{kill-ring-save}) command. You must mark each line for this
-command to succeed, but it does not matter at which end you put point
-or mark.)
-
-@ignore
-@c texi2dvi fails when the name of the section is within ifnottex ...
-For a discussion of how @code{condition-case} deals with error, see
-@ref{Complete kill-region, , The Complete @code{kill-region}
-Definition}.
-@end ignore
+you. Alternatively, for silence, you may copy the region of each line
+with the @kbd{M-w} (@code{kill-ring-save}) command. You must mark
+each line for this command to succeed, but it does not matter at which
+end you put point or mark.)
@need 1250
@noindent
The @code{current-kill} function changes the element in the kill ring
to which @code{kill-ring-yank-pointer} points. (Also, the
@code{kill-new} function sets @code{kill-ring-yank-pointer} to point
-to the latest element of the the kill ring.)
+to the latest element of the the kill ring. The @code{kill-new}
+function is used directly or indirectly by @code{kill-append},
+@code{copy-region-as-kill}, @code{kill-ring-save}, @code{kill-line},
+and @code{kill-region}.)
@need 1500
The @code{current-kill} function is used by @code{yank} and by
@end group
@end smallexample
-In addition, the @code{kill-new} function sets
+Remember also that the @code{kill-new} function sets
@code{kill-ring-yank-pointer} to the latest element of the the kill
-ring. And indirectly so does @code{kill-append}, since it calls
-@code{kill-new}. In addition, @code{kill-region} and @code{kill-line}
-call the @code{kill-new} function.
+ring, which means that all the functions that call it set the value
+indirectly: @code{kill-append}, @code{copy-region-as-kill},
+@code{kill-ring-save}, @code{kill-line}, and @code{kill-region}.
@need 1500
Here is the line in @code{kill-new}, which is explained in
@code{interprogram-paste} and is for copying to another program. It
is not for copying within this instance of GNU Emacs. Most window
systems provide a facility for interprogram pasting. Sadly, that
-facility usually provides only for the lasted element. Most windowing
+facility usually provides only for the last element. Most windowing
systems have not adopted a ring of many possibilities, even though
Emacs has provided it for decades.
@need 2000
Let us consider the `if not' or else-part of the @code{current-kill}
function. (The then-part uses the the @code{kill-new} function, which
-we have already described. (@xref{kill-new function, , The
+we have already described. @xref{kill-new function, , The
@code{kill-new} function}.)
@smallexample
signals an error.
@need 1000
-Note that the @code{or} expression is very similar to writing
+Note that the @code{or} expression is very similar to testing length
+with an @code{if}:
@findex zerop
@findex error
true, the then-part of the @code{if} is evaluated. The then-part is a
list starting with the function @code{error}, which is a function that
is similar to the @code{message} function
-(@pxref{message, , The @code{message} Function}), in that
+(@pxref{message, , The @code{message} Function}) in that
it prints a one-line message in the echo area. However, in addition
to printing a message, @code{error} also stops evaluation of the
function within which it is embedded. This means that the rest of the
Next, either the optional @code{do-not-move} argument is true or the
current value of @code{kill-ring-yank-pointer} is set to point to the
-list, the first element of which is returned even if the
-@code{do-not-move} argument is true.
+list. Finally, another expression returns the first element of the
+list even if the @code{do-not-move} argument is true.
@menu
* Digression concerning error::
@smallexample
@group
;; kill-ring-yank-pointer @r{and} kill-ring @r{have a length of four}
-(nthcdr (mod (- 0 4) 4) ; (mod -4 4) @result{} 0
+;; @r{and} (mod (- 0 4) 4) @result{} 0
+(nthcdr (mod (- 0 4) 4)
'("fourth line of text"
"third line"
"second piece of text"
@findex yank
After learning about @code{current-kill}, the code for the
-@code{yank} function is almost easy. It has only one tricky part, which is
-the computation of the argument to be passed to @code{rotate-yank-pointer}.
+@code{yank} function is almost easy.
+
+The @code{yank} function does not use the
+@code{kill-ring-yank-pointer} variable directly. It calls
+@code{insert-for-yank} which calls @code{current-kill} which sets the
+@code{kill-ring-yank-pointer} variable.
@need 1250
The code looks like this:
returned by @code{current-kill}, but removes some text properties from
it.
-However, before getting to that expression, the function set the value
+However, before getting to that expression, the function sets the value
of @code{yank-window-start} to the position returned by the
@code{(window-start)} expression, the position at which the display
-currently starts. It also set @code{this-command} and pushed the
-mark.
+currently starts. The @code{yank} function also sets
+@code{this-command} and pushes the mark.
After it yanks the appropriate element, if the optional argument is a
-@sc{cons} rather than a number or nothing, put point at beginning of
-the yanked text and mark at its end. (The @code{prog1} function is
-like @code{progn} but returns the value of its first argument rather
-than the value of its last argument. Its first argument is forced to
-return the buffer's mark as an integer. You can see the documentation
-for these functions by placing point over them in this buffer and then
-typing @kbd{C-h f} (@code{describe-function}) followed by a @kbd{RET};
-the default is the function.)
+@sc{cons} rather than a number or nothing, it puts point at beginning
+of the yanked text and mark at its end.
+
+(The @code{prog1} function is like @code{progn} but returns the value
+of its first argument rather than the value of its last argument. Its
+first argument is forced to return the buffer's mark as an integer.
+You can see the documentation for these functions by placing point
+over them in this buffer and then typing @kbd{C-h f}
+(@code{describe-function}) followed by a @kbd{RET}; the default is the
+function.)
The last part of the function tells what to do when it succeeds.
@findex yank-pop
After understanding @code{yank} and @code{current-kill}, you know how
-to approach the @code{yank-pop} function Leaving out the documentation
-to save space, it looks like this:
+to approach the @code{yank-pop} function. Leaving out the
+documentation to save space, it looks like this:
@c GNU Emacs 22
@smallexample
The function is interactive with a small @samp{p} so the prefix
argument is processed and passed to the function. The command can
only be used after a previous yank; otherwise an error message is
-sent. This check uses the variable @code{last-command} which is
-set by @code{yank} and is discussed elsewhere. (@xref{copy-region-as-kill}.)
+sent. This check uses the variable @code{last-command} which is set
+by @code{yank} and is discussed elsewhere.
+(@xref{copy-region-as-kill}.)
The @code{let} clause sets the variable @code{before} to true or false
depending whether point is before or after mark and then the region
special format. The format is a question mark followed by a blank
space, like this, @samp{? }. @xref{Character Type, , Character Type,
elisp, The GNU Emacs Lisp Reference Manual}, for a description of the
-syntax for characters.
+syntax for characters. (Of course, you might want to replace the
+blank space by some other character @dots{} You know what to do.)
The @code{number-to-string} function is used in the concatenation
expression, to convert the number to a string that is concatenated
Press @key{RET} to evaluate the expression.
@end enumerate
-Emacs will print labels vertically, the top one being
-@w{@samp{10 -@w{ }}}. (The @code{print-graph} function
-will pass the value of @code{height-of-top-line}, which
-in this case would end up as 15.)
+Emacs will print labels vertically, the top one being @w{@samp{10 -@w{
+}}}. (The @code{print-graph} function will pass the value of
+@code{height-of-top-line}, which in this case will end up as 15,
+thereby getting rid of what might appear as a bug.)
@need 2000
@node print-X-axis, Print Whole Graph, print-Y-axis, Full Graph
@noindent
(Note that the value of @code{graph-blank} is set by another
@code{defvar}. The @code{boundp} predicate checks whether it has
-already been set; @code{boundp} returns @code{nil} if it has not.
-If @code{graph-blank} were unbound and we did not use this conditional
-construction, in GNU Emacs 21, we would enter the debugger and see an
-error message saying
-@samp{@w{Debugger entered--Lisp error:} @w{(void-variable graph-blank)}}.)
+already been set; @code{boundp} returns @code{nil} if it has not. If
+@code{graph-blank} were unbound and we did not use this conditional
+construction, in a recent GNU Emacs, we would enter the debugger and
+see an error message saying @samp{@w{Debugger entered--Lisp error:}
+@w{(void-variable graph-blank)}}.)
@need 1200
Here is the @code{defvar} for @code{X-axis-tic-symbol}:
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