bug#7492: 23.2; cl loop over the windows: infinite loop, info doc

bug#7492: 23.2; cl loop over the windows: infinite loop, info doc

[Michael Heerdegen]

In GNU Emacs 23.2.1 (i486-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2010-08-14 on raven, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
configured using `configure  '--build' 'i486-linux-gnu' '--build' 'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var/lib' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs23:/etc/emacs:/usr/local/share/emacs/23.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.2/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.2/leim' '--with-x=yes' '--with-x-toolkit=lucid' '--with-toolkit-scroll-bars' '--without-gconf' 'build_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -g -O2' 'LDFLAGS=-g' 'CPPFLAGS=''

Hello,

if you evaluate the following sexp in Emacs -Q, you get an infinitive
loop:

(progn
  (require 'cl)
  (select-window (minibuffer-window))
  (loop for win being the windows do 'nothing))

This should be fixed.


Moreover, the "CL" info manual should be clarified here:
  (cl)Top > Control Structure > Loop Facility > For Clauses

For looping over "the windows", it only says:

`for VAR being the windows [of FRAME]'
     This clause iterates over the windows (in the Emacs sense) of the
     current frame, or of the specified FRAME.

It's not clear if/when the minibuffer window is included and in which
order the iteration is done.

bug#7492: 23.2; cl loop over the windows: infinite loop, info doc

[Glenn Morris]

Michael Heerdegen wrote:

> For looping over "the windows", it only says:
>
> `for VAR being the windows [of FRAME]'
>      This clause iterates over the windows (in the Emacs sense) of the
>      current frame, or of the specified FRAME.
>
> It's not clear if/when the minibuffer window is included and in which
> order the iteration is done.

By experiment, the minibuffer is not included, which is why it loops
forever if you force it to start there. Does the order matter? Anyway,
it's the order that `next-window' gives.

`loop' can probably be improved, but I suggest using `walk-windows'
(which has well-defined, flexible behaviour wrt the minibuffer)
instead and will add a note to cl.texi to this effect.

bug#7492: 23.2; cl loop over the windows: infinite loop, info doc

[Glenn Morris]

Version: 24.1

Fixed the manual in 23.3; fixed the infinite loop in 24.1.