# $EPIC: set_output_rewrite.txt,v 1.2 2006/08/20 15:02:36 sthalik Exp $
======Synopsis:======
[[set]] output_rewrite

======Description:======
If this /[[SET]] is defined (by default, it is un-set), then every
time a LOGICAL line of output is about to be sent to a window, the
/[[SET]] value is expanded, and the result of that expansion is substituted
for the original text.  The expansion is parsed in the context that:

|  $0   | The window refnum the output is going to |
|  $1-  | The text itself                          |

======Examples:======
This would timestamp all output to all windows:
	/SET OUTPUT_REWRITE $Z $1-

This would timestamp all output to all windows with a custom timestamp
format:
  /SET OUTPUT_REWRITE $strftime(%X) $1-

This would return proceed all output to all windows with the output of
the user defined function $myfunc() called with the window number.
	/SET OUTPUT_REWRITE $myfunc($0) $1-

======Notes:======
When changing /[[set]] output_rewrite inside of an alias, please remember
that $'s are expanded before the /set is called, and so things like
$1- or $myfunc($0) would be expanded at the /set time and not at the
rewrite time.  Make sure to double up your $$'s in such cases!

======Practical:======
For every line of output that goes to the screen, /[[on window]] is
thrown.  However, /[[on window]] cannot be recursively called, so
there are some instances where output goes to the window without
/[[on window]] having been thrown.  This makes it hard to write
general purpose time stamp handlers.  Therefore, a general purpose
way of doing final-editing on window output is needed.  This set
provides that capability.

======Performance Note:======
This is a very expensive operation, but is cheaper than using
an /[[on window]], and probably less of a hassle than redefining
a zillion other /on's.  It also is pretty reliable, since it
will always be honored for all lines of output.