[R] How to 'stamp' a plot with meta-data?

[Itay Furman]

Dear R users,

Sometimes, for tracking purposes, I am interested to add to a 
plot some metadata such as
* the date it was produced
* filename that stores the plot
* perhaps data sources, author, etc

Ideally, I would like to be able to do this for any kind of plot, 
plot(), barplot(), hist(), etc.; and, to be able to produce 
plots with or without the metadata by a simple toggle mechanism.

Something like:

# 'Clean' plot
some.plot.func(<args>)	# plot() or barplot() or ...

# Now with metadata
options(metadata=TRUE)	# Or some other toggle mechanism

some.plot.func(<args>)	# Same plot as above, but with wider 
			# bottom margins that show the 
			# metadata.

So far I looked in "Introduction to R" and tried to find hints 
using help.search() without success.

Is it possilbe to do?
Any suggestions or pointers as to how to do it are appreciated.
Even partial solution in which the plot is set up to accomodate 
metadata in the margins, but the data needs to be added manually 
after plot()ting will be great.

	Thanks in advance,
	Itay

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itayf at fhcrc.org		Fred Hutchinson Cancer Research Center