Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!njin!princeton!phoenix!ghh
From: ghh@cognito.princeton.edu (Gilbert Harman)
Newsgroups: gnu.emacs
Subject: Re: save-context-predicate in saveconf.el
Message-ID: <GHH.89Jul25123528@cognito.princeton.edu>
Date: 25 Jul 89 16:35:28 GMT
References: <GHH.89Jul24201245@cognito.princeton.edu>
	<1989Jul25.145204.3015@talos.uucp>
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Organization: Princeton University Cognitive Science Lab
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In-reply-to: kjones@talos.uucp's message of 25 Jul 89 14:52:04 GMT

In article <1989Jul25.145204.3015@talos.uucp> kjones@talos.uucp (Kyle Jones) writes:

   Gilbert Harman writes:
    > This is what I tried in my .emacs file so as to prevent my
    > RMAIL file from being remembered.
    > 
    > (setq save-context-predicate
    >   (function (lambda (w)
    > 	      (and (buffer-file-name (window-buffer w))
    > 		   (not (string-match "\\(^\\(/usr\\)?/tmp/\\)\\|RMAIL"
    > 				      (buffer-file-name (window-buffer w)))))))
    > )

   This won't work unless the RMAIL buffer is in a window.  The value of
   save-context-predicate is called for each *window*, not each buffer.
   Perhaps save-context-predicate's semantics should be changed to the
   latter.

Thanks for the pointer.  I have a quick and dirty solution
that introduces a new variable, save-buffer-predicate,
initially defined as follows:

(defvar save-buffer-predicate
  (function (lambda (w)
	      (and (not (string-match "\\(^\\(/usr\\)?/tmp/\\)\\|RMAIL"
				      w)))))

  "*Value is a predicate function which determines which buffers' contexts
are saved.  When the `save-context' command is invoked and
save-buffer-context is not nil, this function will be called once for each
existing Emacs buffer.  The function should accept one argument which will
be a buffer name, and should return non-nil if the buffer's context
should be saved.")

Then I modified the save-context function by inserting an
application of this function:

...
	(if save-buffer-context
	    (mapcar
	     (function
	      (lambda (b)
		(set-buffer b)
		(cond ((and buffer-file-name
			    (funcall save-buffer-predicate buffer-file-name))
		       (prin1 buffer-file-name context-buffer)
		       (princ " " context-buffer)
		       (prin1 (point) context-buffer)
		       (princ "\n" context-buffer)))))
	     (buffer-list)))
...

The antecedent in the cond originally checked to make sure
that buffer-file-name is not nil.  This now also checks to
make sure the name isn't the name of a file you don't want
to save the context for.

This seems to work.

--
		       Gilbert Harman
                       Princeton University Cognitive Science Laboratory
	               221 Nassau Street, Princeton, NJ 08542
			      
		       ghh@princeton.edu
		       HARMAN@PUCC.BITNET