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More listener questions

   Date: Mon, 21 Mar 1994 12:44:16 -0500
   From: Adam Carlson <carlson%lindy@cs.umass.edu>

   I have tried using the recently posted select-file function in an
   application which has its top-level based on the clim lisp-listener
   demo.

   The following code may be added to the code I posted in my previous
   message with questions about the listener.  If you type :Choose File
   then a file browser box comes up, but then after you hit OK, a second
   file browser appears and the result of that select-file and the first
   one appear to be concatenated.  A notification is made about
   extraneous characters in the input, and the input is not usable.  I
   can reproduce this by typing (accept 'command) at the listener prompt
   (implying that the problem is in (accept 'command), not the listener
   or (accept 'command-or-form), but when I create a similar command in a
   non-listener application, it works fine.

   I traced accept and select-file, and it appears that (accept
   'command-or-form) calls (accept 'command), which calls (accept
   'command-name) and then (accept 'my-pathname) which calls select-file,
   select-file returns, (accept 'command) throws.  Then (accept 'command)
   is called again, leading to a second select-file.  My guess is that
   the way the accept command method is implemented it does one pass
   which gets the input and a second which constructs the command object.

The real problem here is that your code is not taking the input editor
into account.  The control flow of the input editor loops, which is
why you are the parsing functions are being called more than once.

   I also have a question about programmatic interaction with the
   file-browser.  The original post said select-file specializes on
   application-frames so that you could customize its behavior.  I would
   like to change the default filter (in particular, I'd like to specify
   the file type, or filename extension that is acceptable.)  How do I go
   about doing that.  There isn't any documentation on how to communicate
   to select-file.

   ;;;-------------------------------------------------------------------
   ;;; Select-file
   ;;;-------------------------------------------------------------------

   (define-presentation-type my-pathname () :inherit-from '(pathname))

   #+clim-2
   (define-presentation-method accept ((type my-pathname)
				       (stream t) (view t) &key)
     (let ((pathname (select-file *application-frame*)))
       (presentation-replace-input stream pathname 'pathname view)
       (values pathname 'my-pathname)))

My guess is that you want the accept method above to check the value
of stream-rescanning-p.  When it is NIL, this should do just what you
have above.  When T, it should call (accept 'pathname).

This is a pretty subtle thing here...

   (define-lisp-listener-command (com-choose-file :name t :menu t)
     ((pathname 'my-pathname :prompt #+clim-1 "Pathname" #+clim-2 nil))
     (present pathname 'pathname))

   (define-lisp-listener-command (com-another-choose-file :name t :menu t)
     ()
     (let ((pathname (accept 'my-pathname)))
       (terpri)
       (present pathname 'pathname)))
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