Refactor TypeCheck.hs to eleborate instead of just typecheck

(As discussed with Stephanie:)

We would like to experiment with various features for the surface language 
without having to reimplement the entire type system twice (once for the core 
and one for the sugared version). The route of least effort seems to be to 
refactor the typechecker so that instead of just checking the program, it 
produces a Core Trellys program as output.

There will be one option which causes it to signal an error if given a program 
which is not in Core Trellys already -- in this mode it simply serves as a 
typechecker for Core Trellys. But when that option is off, it could take 
programs using additional features, and elaborate them into Core programs.

Original issue reported on code.google.com by vilhelm....@gmail.com on 2 Jan 2011 at 10:31

sweirich / trellys

Refactor TypeCheck.hs to eleborate instead of just typecheck #12