GNU bug report logs - #3752
23.0.95; I can not understant a sentence in Intro to Emacs Lisp .

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: waterloo <waterloo2005 <at> gmail.com>
To: emacs-pretest-bug <at> gnu.org
Subject: 23.0.95; I can not understant a sentence in Intro to Emacs Lisp .
Date: Sat, 4 Jul 2009 21:00:07 +0800

[Message part 1 (text/plain, inline)]

--text follows this line--
In section 8.5.1 in the manual `Introduction to Emacs Lisp'.  I can
not understant what is `readily settable variable' in second
paragraph.  Thanks . waterloo2005 <at> gmail.com

In GNU Emacs 23.0.95.1 (i686-pc-linux-gnu, GTK+ Version 2.14.7)
 of 2009-06-21 on laptop
Windowing system distributor `The X.Org Foundation', version 11.0.10503000
configured using `configure  '--prefix=/usr' '--build=i686-pc-linux-gnu'
'--host=i686-pc-linux-gnu' '--mandir=/usr/share/man'
'--infodir=/usr/share/info' '--datadir=/usr/share' '--sysconfdir=/etc'
'--localstatedir=/var/lib' '--program-suffix=-emacs-23'
'--infodir=/usr/share/info/emacs-23' '--with-sound' '--with-x'
'--without-toolkit-scroll-bars' '--with-gif' '--with-jpeg' '--with-png'
'--with-rsvg' '--with-tiff' '--with-xpm' '--with-xft' '--without-libotf'
'--without-m17n-flt' '--with-x-toolkit=gtk' '--without-hesiod'
'--without-kerberos' '--without-kerberos5' '--with-gpm' '--with-dbus'
'build_alias=i686-pc-linux-gnu' 'host_alias=i686-pc-linux-gnu' 'CFLAGS=-O2
-march=pentium-m -pipe' 'LDFLAGS=-Wl,-O1''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: en_US.UTF-8
  value of $LC_CTYPE: zh_CN.UTF-8
  value of $LC_MESSAGES: en_US.UTF-8
  value of $LC_MONETARY: en_US.UTF-8
  value of $LC_NUMERIC: en_US.UTF-8
  value of $LC_TIME: en_US.UTF-8
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=SCIM
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Minor modes in effect:
  reftex-mode: t
  TeX-fold-mode: t
  flyspell-mode: t
  TeX-source-specials-mode: t
  minibuffer-depth-indicate-mode: t
  icicle-mode: t
  show-paren-mode: t
  display-time-mode: t
  global-auto-complete-mode: t
  auto-complete-mode: t
  desktop-save-mode: t
  yas/minor-mode: t
  auto-image-file-mode: t
  outline-minor-mode: t
  shell-dirtrack-mode: t
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Recent input:
<drag-mouse-1> <help-echo> <down-mouse-1> <mouse-1>
<down-mouse-5> <mouse-5> <help-echo> <help-echo> <down-mouse-1>
<help-echo> <help-echo> <help-echo> <down-mouse-4>
<mouse-4> <down-mouse-1> <mouse-movement> <mouse-movement>
<help-echo> <drag-mouse-1> <help-echo> <down-mouse-1>
<mouse-1> <down-mouse-1> <mouse-1> <help-echo> <help-echo>
<down-mouse-4> <mouse-4> <double-down-mouse-4> <double-mouse-4>
<down-mouse-5> <mouse-5> <down-mouse-4> <mouse-4> <help-echo>
<tool-bar> <Exit> <help-echo> <tool-bar> <Exit> <help-echo>
<tool-bar> <Exit> <help-echo> <help-echo> <help-echo>
<tool-bar> <kill-buffer> <down-mouse-4> <mouse-4> <down-mouse-4>
<mouse-4> <double-down-mouse-4> <double-mouse-4> <down-mouse-4>
<mouse-4> <double-down-mouse-4> <double-mouse-4> <help-echo>
<down-mouse-3> <mouse-3> <help-echo> <down-mouse-1>
<mouse-1> <help-echo> <menu-bar> <buffer> C-h <help-echo>
<tool-bar> <kill-buffer> <menu-bar> <buffer> C-h <help-echo>
<tool-bar> <kill-buffer> <help-echo> <menu-bar> <buffer>
C-h <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <menu-bar> <file> <kill-buffer> <help-echo>
<menu-bar> <buffer> C-h <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <menu-bar> <file> <kill-buffer> <help-echo>
<help-echo> <menu-bar> <buffer> C-h <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <menu-bar> <file>
<kill-buffer> <help-echo> <help-echo> <help-echo> <help-echo>
<menu-bar> <buffer> C-h <down-mouse-4> <mouse-4> <double-down-mouse-4>
<double-mouse-4> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <menu-bar>
<file> <kill-buffer> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <down-mouse-3> <mouse-3> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <tool-bar> <latex> <help-echo>
<help-echo> <down-mouse-5> <mouse-5> <down-mouse-1>
<mouse-movement> <mouse-1> <return> <right> <right>
<right> <right> <right> <right> <right> <right> <down-mouse-1>
<mouse-1> SPC <delete> <delete> <delete> <delete> <delete>
<delete> <delete> <down-mouse-1> <mouse-1> <down-mouse-1>
<mouse-1> SPC <help-echo> <help-echo> <help-echo> <tool-bar>
<save-buffer> <down-mouse-1> <mouse-movement> <mouse-movement>
<drag-mouse-1> C-c C-p C-r <help-echo> <down-mouse-1>
<mouse-1> <help-echo> <down-mouse-3> <mouse-3> <help-echo>
<down-mouse-1> <mouse-movement> <mouse-movement> <drag-mouse-1>
<help-echo> <down-mouse-1> <mouse-movement> <mouse-1>
% <help-echo> <down-mouse-3> <mouse-3> <backspace>
<help-echo> <tool-bar> <undo> <help-echo> <tool-bar>
<undo> <help-echo> <help-echo> <help-echo> <down-mouse-1>
<help-echo> <mouse-movement> <mouse-1> <help-echo>
<down-mouse-1> <mouse-movement> <help-echo> <mouse-movement>
<mouse-movement> <drag-mouse-1> <help-echo> C-c C-p
C-c C-r <down-mouse-1> <mouse-1> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> M-x r e p o <tab>
r <tab> <return>

Recent messages:
Type `C-c C-l' to display results of compilation.
Quit
Saving file /media/bak/latex/_region_.tex...
Wrote /media/bak/latex/_region_.tex
Type `C-c C-l' to display results of compilation.
locating previews...
Mark set
Type `C-c C-l' to display results of compilation.
Undo! [2 times]
Computing completion candidates...

[Message part 2 (text/html, inline)]

Message #8 received at 3752 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: waterloo <waterloo2005 <at> gmail.com>
Cc: 3752 <at> debbugs.gnu.org
Subject: Re: bug#3752: 23.0.95; I can not understant a sentence in Intro to Emacs Lisp .
Date: Sat, 04 Jul 2009 19:11:46 -0400

waterloo wrote:

> --text follows this line--
> In section 8.5.1 in the manual `Introduction to Emacs Lisp'.  I can
> not understant what is `readily settable variable' in second
> paragraph.

Does the following make it clearer?

   When you specified a variable using the `defvar' special form, you
   could distinguish a variable that a user might want to change from
   others by typing an asterisk,...

It should be read in the context of the previous paragraph.

Message #11 received at 3752 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: waterloo <waterloo2005 <at> gmail.com>
To: Glenn Morris <rgm <at> gnu.org>
Subject: Re: bug#3752: 23.0.95; I can not understant a sentence in Intro to 
	Emacs Lisp .
Date: Sun, 5 Jul 2009 10:13:32 +0800

[Message part 1 (text/plain, inline)]

yes,it is clearer . thanks

In 11.1.2 An Example:`print-elements-of-list', I can not understand why
there is a `nil' in the context .

thanks
If I shoud file a new bug for this question?
I still use emacs23.0.95 .

2009/7/5 Glenn Morris <rgm <at> gnu.org>

> waterloo wrote:
>
> > --text follows this line--
> > In section 8.5.1 in the manual `Introduction to Emacs Lisp'.  I can
> > not understant what is `readily settable variable' in second
> > paragraph.
>
> Does the following make it clearer?
>
>   When you specified a variable using the `defvar' special form, you
>   could distinguish a variable that a user might want to change from
>   others by typing an asterisk,...
>
> It should be read in the context of the previous paragraph.
>

[Message part 2 (text/html, inline)]

Message #14 received at 3752 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: waterloo <waterloo2005 <at> gmail.com>
Cc: 3752 <at> debbugs.gnu.org
Subject: Re: bug#3752: 23.0.95; I can not understant a sentence in Intro to 
	Emacs Lisp .
Date: Sat, 4 Jul 2009 22:30:29 -0400

[Please use "reply to all".]

waterloo wrote (on Sun, 5 Jul 2009 at 10:13 +0800):

> yes,it is clearer . thanks
> 
> In 11.1.2 An Example:`print-elements-of-list', I can not understand why
> there is a `nil' in the context .

This is explained at the end of the section:

 Since the last expression in the function is the `while' loop, and
 since `while' loops always return `nil', a `nil' is printed after the
 last element of the list.

Message #19 received at 3752 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: waterloo <waterloo2005 <at> gmail.com>
To: Glenn Morris <rgm <at> gnu.org>
Cc: 3752 <at> debbugs.gnu.org
Subject: Re: bug#3752: 23.0.95; I can not understant a sentence in Intro to 
	Emacs Lisp .
Date: Sun, 5 Jul 2009 10:47:06 +0800

[Message part 1 (text/plain, inline)]

when test of while is nil , it does not run `print' following it.
who  does print nil ?

or  if all function will print its return value ?

thanks

2009/7/5 Glenn Morris <rgm <at> gnu.org>

>
> [Please use "reply to all".]
>
> waterloo wrote (on Sun, 5 Jul 2009 at 10:13 +0800):
>
> > yes,it is clearer . thanks
> >
> > In 11.1.2 An Example:`print-elements-of-list', I can not understand why
> > there is a `nil' in the context .
>
> This is explained at the end of the section:
>
>  Since the last expression in the function is the `while' loop, and
>  since `while' loops always return `nil', a `nil' is printed after the
>  last element of the list.
>

[Message part 2 (text/html, inline)]

Message #22 received at 3752 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: waterloo <waterloo2005 <at> gmail.com>
Cc: 3752 <at> debbugs.gnu.org
Subject: Re: bug#3752: 23.0.95; I can not understant a sentence in Intro to  Emacs Lisp .
Date: Sun, 05 Jul 2009 20:58:11 -0400

waterloo wrote:

> when test of while is nil , it does not run `print' following it.
> who  does print nil ?
>
> or  if all function will print its return value ?

As explained in the earlier section of the manual (on "Evaluation"),
evaluating a function with C-x C-e prints the return value. For example

(+ 2 2)

or

(progn
  (princ "Evaluating with C-x C-e prints the return value.\n")
  42)

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