CMSC 221/321
Homework set 3
Due: Tuesday, Oct 26, 2010

Homework 3.1: Write an ML program implementing substitution-based,
call-by-value semantics (Fun[BSv]) for the Fun language. Test your
implementation by computing (fact 3) (factorial of 3).

Homework 3.2: Define an environment-based call-by-name big-step
semantics for Fun (Fun[BSEn]). (Hint: Recall that the environment-based
semantics for SAEL(by-name) needed to employ expression closures
(<e,E>) in environment bindings. You will also need function closures
in this semantics. These are just expression closures where the
expression is a Fun(x,e) expression.)

Homework 3.3: Define a CR-style small-step transition semantics for
Fun (substitution-based).

Homework 3.4: Extend the CEK abstract machine to handle Fun.
Test it by writing an ML implementation and computing (fact 3)
again as in Homework 3.1.