A Poor Man's Logic System with First-Class Relations, a printable version , and source (just load it) .

Notes and Examples

code for expand-only.

code for match.

Just load cps?.ss (for ? = A | B | C | D | E | F).

code for cps-tests.ss.

code for cps-tester.ss.

code for type-verifier.ss.

code for kunify.ss.

code for gensyms.ss.

code for Aziz's Interpreter

code for app.ss

code for ooo7.ss The file ooo7.ss is quite simply the file ooo6.ss, but with all the lets rewritten as lets and all the let* rewritten as let*s. This causes all the occurrences of let and let* to disappear. This removes all the lexical context that stores positions. The only changes occurred in OBJECT and def-class.

Using an Abstracted Interpreter to Understand Abstract Interpretation (ps)

Using an Abstracted Interpreter to Understand Abstract Interpretation (pdf)

From Direct Style to Monadic Style through Continuation-Passing Style , a printable version, and source (just load it).

Direct Style from Monadic Style and Back , a printable version, and source (just load it).

Assignment for April 11th class.
Here is r* a lambda-calculus reducer.

(define r*
  (lambda (e)
    (let ((t (r0 e (lambda (hole) hole))))
      (cond
	((equal? t e) t)
	(else (r* t))))))

(define r0
  (lambda (e ctx)
    (match e
      (,x (guard (symbol? x)) (ctx x))
      ((lambda (,id) ,body)
       (r0 body (lambda (hole) (ctx `(lambda (,id) ,hole)))))
          ;;; in Scheme we don't go under the lambda, but here we do
          ;;; just for the fun of it.
      ((,rator ,rand)
       (match rator
	 (,f (guard (symbol? f)) (r0 rand (lambda (hole) (ctx `(,f ,hole)))))
	 ((lambda (,id) ,body) (ctx (beta-subst rand id body)))
	 (,else (r0 rator (lambda (hole) (ctx `(,hole ,rand))))))))
	  ;;; We have chosen to evaluate the rator first.
          ;;; obviously this is arbitrary.

Grab your body[id <- rand] from last semester's handout to implement

(beta-subst rand id body)

Finish implementing this reducer by defining beta-subst (see Stoy) and then try to mini-kanrenize it. ... Dan