Foo is Not a Variable
Prints an explanation of the placeholder name
foo is used by computer scientists as a
place holder, to represent the name of any desired object or
function. It is not the name of an actual object or function;
it serves only as an example, to explain a concept.
However, many users misinterpret this convention, and actually
type the command
foo(). Then they email the
package author to inform them that
foo is not defined.
To avoid this correspondence, we have now defined an object
foo() prints a message explaining that
is not really the name of a variable.
The function can be executed simply by typing