||An ExpressionFunction is a Function that is created from an expression and a list
of variables that serve as the parameter(s) of the function.
||An object belonging to a concrete subclass of FunctionParserExtesion is a
mathematical function that can be registered with a Parser and then used in
strings that are parsed by that parser.
||The SummationParser class makes it possible to use summations such as sum(i,1,5,x^i) in a Parser.
||A TableFunction is a function that is specified by a table of (x,y)-points.
||A TableFunctionGraph is a Drawable object that can be added to a CoordinateRect (or DisplayCanvas).
||A TableInputFunction is a Panel that can be used to define a TableFunction
or to edit an existing TableFunction.
||A WrapperFunction contains another function and delegates to it
all calls to methods from the Function interface, except for calls
to setName() and getName().