Re: dired-man can't deal with compressed pages

[Juri Linkov <juri@jurta.org>]

Eli Zaretskii <eliz@elta.co.il> writes:
> I'm not sure this is the right way of solving the problem.  For
> starters, the "-l" switch is not portable: most versions of `man'
> don't support it.  And after thinking for a while, I don't see any way
> of forcing those versions of `man' who don't have "-l" to format a
> specific file.  I presume this is the reason why dired-x runs nroff
> directly.

I agree that this will not work for man who don't have the -l option.
On the other hand, man with the -l option should take the advantage of
this option.  So I think a good solution is to let users to choose
the command line they want, like in the patch below.

> If the only problem with the current code is that it doesn't support
> compressed man pages, perhaps we could detect compressed files and
> decompress them on the fly.

I think it's better not to duplicate what man already does.  Users
can construct the command line as they want.

> As for preprocessors, I don't know.  If this is important, we could
> blindly run the file through all of them, for example, or have a user
> option to do that.

Blindly running the file through all preprocessors will fail if some
preprocessor is not installed.  But having a user option will allow
the user to specify the command line with needed preprocessors.

> Yet another possible solution is to use functions from woman.el, which
> IIRC has a special command to format a single file.  However, I don't
> remember how well it supports various preprocessors.

There is already a dired binding to `W' key in woman.el.
So users desiring a woman can get her with this key.

Index: emacs/lisp/dired-x.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/dired-x.el,v
retrieving revision 1.52
diff -c -r1.52 dired-x.el
*** emacs/lisp/dired-x.el	28 Sep 2003 09:03:45 -0000	1.52
--- emacs/lisp/dired-x.el	22 Feb 2004 18:29:00 -0000
***************
*** 1273,1285 ****
  
  ;;; Run man on files.
  
  (defun dired-man ()
    "Run man on this file.  Display old buffer if buffer name matches filename.
  Uses ../lisp/man.el of \\[manual-entry] fame."
    (interactive)
    (require 'man)
    (let ((file (dired-get-filename))
!         (manual-program "nroff -man -h"))
      (Man-getpage-in-background file)))
  
  ;;; Run Info on files.
--- 1273,1293 ----
  
  ;;; Run man on files.
  
+ (defvar dired-man-command "man -l"
+   "*Default man command.  If your man don't support the -l option,
+ then to display compressed man files you can set this variable to
+ a string like \"gzip -dc %s | tbl | nroff -man -h\" where %s
+ is a placeholder for the man file name.")
+ 
  (defun dired-man ()
    "Run man on this file.  Display old buffer if buffer name matches filename.
  Uses ../lisp/man.el of \\[manual-entry] fame."
    (interactive)
    (require 'man)
    (let ((file (dired-get-filename))
!         (manual-program (read-from-minibuffer
!                          "Man command: " dired-man-command nil nil
!                          'dired-shell-command-history)))
      (Man-getpage-in-background file)))
  
  ;;; Run Info on files.
Index: emacs/lisp/man.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/man.el,v
retrieving revision 1.132
diff -c -r1.132 man.el
*** emacs/lisp/man.el	16 Feb 2004 18:20:31 -0000	1.132
--- emacs/lisp/man.el	22 Feb 2004 18:29:01 -0000
***************
*** 486,498 ****
  (defsubst Man-build-man-command ()
    "Builds the entire background manpage and cleaning command."
    (let ((command (concat manual-program " " Man-switches
! 			 ; Stock MS-DOS shells cannot redirect stderr;
! 			 ; `call-process' below sends it to /dev/null,
! 			 ; so we don't need `2>' even with DOS shells
! 			 ; which do support stderr redirection.
! 			 (if (not (fboundp 'start-process))
! 			     " %s"
! 			   (concat " %s 2>" null-device))))
  	(flist Man-filter-list))
      (while (and flist (car flist))
        (let ((pcom (car (car flist)))
--- 500,514 ----
  (defsubst Man-build-man-command ()
    "Builds the entire background manpage and cleaning command."
    (let ((command (concat manual-program " " Man-switches
!                          (cond
!                           ;; Already has %s
!                           ((string-match "%s" manual-program) "")
!                           ;; Stock MS-DOS shells cannot redirect stderr;
!                           ;; `call-process' below sends it to /dev/null,
!                           ;; so we don't need `2>' even with DOS shells
!                           ;; which do support stderr redirection.
!                           ((not (fboundp 'start-process)) " %s")
!                           ((concat " %s 2>" null-device)))))
  	(flist Man-filter-list))
      (while (and flist (car flist))
        (let ((pcom (car (car flist)))

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