Thunk optimization. #22
Description
The current version of Harper.Interpreter.Thunk engine creates many unnecessary thunks. To list some:
- Wrapping a thunk into a thunk is unnecessary.
- Wrapping any object expression other than variables into a thunk is unnecessary.
- Wrapping literals into thunks is unnecessary.
etc.
Most of these can be optimized away. First we need to identify a list of cases when thunks are absolutely necessary and then make sure that we only wrap these cases into thunks.