Started deinterleaving frontend and backend.
Some consistency checks.
Remove states.
Remove proc.
Purely functional implementation for externals.
Move reduce state and introduce Expand.
Progress on expansion.
Further implementation of Expand.
Split backends.
Remove RState.
More generic backend.
Started restoring emit.
Split types.
Progress on backend.
Program emission is compiling.
Started implementation of monad in lambda-terms.
Improve expansion.
Types.
Simplify backend.
Expand modules as expressions.