substitute(arg, env=NULL) quote(arg, env=NULL)
substitute returns the expression which was typed
as the value of a formal argument. quote is a synonym useful to lisp
programmers.
The typical use of this is to create informative
labels for data sets and plots.
The following example shows a simple use of this facility.
It uses the functions deparse and substitute
to create labels for a plot which are character string versions
of the actual arguments to the function myplot.