RE: [h-e-w] Adding to ps-print-hook problems

[Harig, Mark A.]

-----Original Message-----
From: Jeff Rancier [mailto:address@hidden
Sent: Monday, September 16, 2002 4:52 PM
To: address@hidden; David Vanderschel; Peter Davis
Subject: Re: [h-e-w] Adding to ps-print-hook problems


I changed the fourth argument to non-nil, so the value returned wasn't a
string, but a lisp object, and that worked:

(defun jbr-ps-print-n-up-hook ()
  (let ((number-of-pages
  (read-from-minibuffer 
   "N-up number of pages: " "1" nil t nil nil nil)))
    (if number-of-pages
 (setq ps-n-up-printing number-of-pages))))

(add-hook 'ps-print-hook 'jbr-ps-print-n-up-hook)

I'm assuming that based on the following operation (the setq), the
interpreter cast the *generic* object type to the correct type?  Integer
or numeric?

Jeff

=========

You might consider using 'read-no-blanks-input' since no
spaces should be allowed in the number, and the function
is simpler:

(defun jbr-ps-print-n-up-hook ()
  (let ((number-of-pages
                 (read-no-blanks-input "N-up number of pages: " "1")))
    (if number-of-pages
                (setq ps-n-up-printing number-of-pages))))

According to ps-print.el:

;; The variable `ps-n-up-printing' specifies the number of pages per
sheet of
;; paper.  The value specified must be between 1 and 100.  The default
is 1.
;;
;; NOTE: some PostScript printer may crash printing if
`ps-n-up-printing' is
;; set to a high value (for example, 23).  If this happens, set a lower
value.
;;

So, a more robust version of the function would check to verify that
the value is greater than 0 and less than 101.  Or, it might be
acceptable
to constrain the value to be between 1 and 10, inclusive.

(defun jbr-ps-print-n-up-hook ()
  (let ((number-of-pages
                 (read-no-blanks-input "N-up number of pages: " "1")))
        (if (integerp number-of-pages)
                (if (and (> number-of-pages 0) (< number-of-pages 11))
                        (setq ps-n-up-printing number-of-pages)
                  (print "Outside of valid range: 1 to 10" t))
          (print "Not an integer" t))))

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