Re: Starting ispell in some fixed directory

[Slawomir Nowaczyk <slawomir.nowaczyk.847@student.lu.se>]

On Thu, 05 Oct 2006 15:00:47 -0700 (PDT)
"Stuart D. Herring" <herring@lanl.gov> wrote:

#> > #> We could, alternatively, use the directory from which emacs.exe
#> > #> is running, but I do not know how to get it.
#> > #> (with-current-buffer "*scratch*" default-directory) would be
#> > #> good enough for me, but I believe it is even less likely to work
#> > #> reliably.
#> 
#> You can use the variable `invocation-directory'

That's nice :) Seems to be better than temporary-file-directory. Just in
case, I have included an updated patch at the end of this email.

#> but I suppose it's possible for that not to be known in some cases.

Any idea when could it happen? The doc says "[...]The value is nil if
that directory's name is not known.", so I suppose it *is* possible, but
it might be interesting to know when? If I read the code correctly, it
gets its value from argv[0], so it should always be set on w32. Right?

#> Why not just use "/" if it exists, or else continue to call
#> `directory-file-name' and `file-name-directory' repeatedly until the
#> result doesn't change? Namely,
#> 
#> (let ((default-directory default-directory))
#>   (while (not (equal default-directory
#>               (setq default-directory
#>                     (file-name-directory
#>                      (directory-file-name default-directory)))))
#>   ...)

Well, I suppose that would work in all practical cases, but I think it's
too complex for the problem at hand... Besides, at least in principle,
the root of a current drive might still not be the best place to run
ispell from (just in case it turns out to be a removable drive and we
lock it unnecessarily).

#> I can't see how this would ever fail; on Unix-like systems,

There is no problem on Unix-like systems, as those systems allow you to
rename/move/remove/whatever a directory even if you run ispell from it,
so it's OK to make it so. Only Windows is problematic.

#> you have to have access to all parents of a directory to be in it
#> anyway, and on all systems (I believe) there are fixed points. If
#> this turns out to be useful, an obvious `file-system-root' function
#> could be created to put the while loop in one place.

*If* somebody else finds file-system-root function to be useful, then it
might make sense to use it in ispell.el -- but otherwise I think it is
an overkill. YMMV, of course.

**************************************************

--- /EmacsCVS/lisp/textmodes/ispell.el       2006-09-26 20:28:23.092467200 +0200
+++ /Emacs/lisp/textmodes/ispell.el   2006-10-06 00:30:58.450860800 +0200
@@ -2492,7 +2492,8 @@
     (setq ispell-buffer-local-name nil)

     (if ispell-async-processp
-       (let ((process-connection-type ispell-use-ptys-p))
+       (let ((process-connection-type ispell-use-ptys-p)
+              (default-directory (if (memq system-type '(cygwin windows-nt)) invocation-directory default-directory)))
          (apply 'start-process
                 "ispell" nil ispell-program-name
                 "-a"                   ; accept single input lines

**************************************************

-- 
 Best wishes,
   Slawomir Nowaczyk
     ( slawomir.nowaczyk.847@student.lu.se )

Living on Earth may be expensive, but it includes
an annual free trip around the Sun.