* Topics for Midterm 2
** Lambda calculus encodings
** Environment-based interpreter
** Static and Dynamic scoping
** Recursive definitions
** Mutation and store passing
** Call-by-name and Call-by-need
** Call-by-reference

* What won't be on the exam
** Anything covered after Friday, March 5th
** complexities of Scheme/ML syntax
** complexities of ML module system

For this exam, you will need to be able to read and write programs in
O'Caml and in the language implemented in chapter 3 of EOPL. Minor
errors in syntax (such as punctuation) will not be deducted as long as
your answers are unambiguous.

The exam may ask you to:

* Write programs in the untyped lambda calculus using the encodings for let, booleans, and numbers
* Devise new lambda-calculus encodings of simple (non-recursive) expression forms.
* Write programs in a language with dynamic scoping.
* Compare the values of expressions evaluated with static/dynamic scoping.
* Complete the ML implementation of dynamic scoping for let expressions.
* Complete an ML implementation of a variant of letrec.
* Complete a store-passing interpreter for a new expression form.
* Write programs with different forms of mutation (ML-style, Scheme-style, C-style etc.)
* Compare the values of expressions evaluated with Call-by-value/name/need/reference.