Redirect the output of the (display ...) command

[johrndorf]

Is there any way to redirect the output of the (display) command to a file?

[clausb]

Why don't you just write to a file directly? For example:

  (defun to-display()
    (display "foo")
    (display "bar"))

  (defun to-file()
    (with-open-file (out "logfile.txt" :direction :output)
      (print "foo" out)
      (print "bar" out)))

See also http://www.lispworks.com/documentation/HyperSpec/Body/m_w_open.htm

[johrndorf]

That is because the command sd-dump-control-tree seems to be very proud about itself and thinks it has to display the output path in the output window.
I would be happy if I could convince the function to do the task quiet. But I'am afraid there is no way to do this, so I have to redirect the output.

[clausb]

For inspiration only, code completely untested:

(defun my-display(msg &rest r)
  (format t "my-display: ~S ~S" msg r))

(let ((original-display (symbol-function 'display)))

  (setf (symbol-function 'display) (symbol-function 'my-display))

  (display "in block after redirecting")

  ;; or try to call sd-dump-control-tree here

  (setf (symbol-function 'display) original-display)

  (display "in block after restoring"))

See also http://www.clausbrod.de/CoCreateModeling/MacroSymbolFunction

[clausb]

Try this:

(let ((original-display (symbol-function 'display-value)))
  (setf (symbol-function 'display-value)  (lambda(&rest r)))
  (oli:sd-dump-control-tree :filename "c:/temp/tree")
  (setf (symbol-function 'display-value) original-display)

[johrndorf]

Hello,
that works great, thank you very much.