a few things to add to RX

- a proper type system. 
  at the moment, everything is a rational language.
  we would need (at least) terms, numbers, sets, lists, tuples


- a proper module system:

	- non-flat namespace
	- import/export declarations
	
- modules are compiled, resulting in
	
	- object files (containing variable bindings,
	  like normal forms of automata)
	- text files (containing typeset output)
	  these should be \includeonly-able

- all of this gets us dangerously close to a full Haskell.
