kesava / eopl Goto Github PK

Hey, great job starting with the first edition!
Have heard that three editions are three distinct books.
Yet to get into 2nd and 3rd editions but I was working on Chapter 2 of the first one.
I came across the tough cookie that is 2.2.9 and was comparing my results with yours.

These tests on yours seem to give wrong answer on Exercise 2.2.9:

> (car&cdr 'a '() 'fail)
'(lambda (x) ())
> (car&cdr 'a '(() ((a))) 'fail)
'(lambda (x) (car (car (car ()))))
> (car&cdr 'a '(() (a)) 'fail)
'(lambda (x) (car (car ())))
> (car&cdr 'a '(() (b) a) 'fail)
'(lambda (x) (car (cdr ())))
> (car&cdr 'a '(b c d () e (a)) 'fail)
'(lambda (x) (car (car (cdr (cdr cdr)))))
> (car&cdr 'a '(() () a) 'fail)
. . car: contract violation
  expected: pair?
  given: '()

Executing:

(lexical-address '(lambda (x y z) (x (y z)))) gives
=> '(lambda (x y z) ((x : 0 0) (y : 0 1) (z : 0 2)))

which loses the context of application of (x (y z))

Also, single variable functions have an extra bracket around them:

(lexical-address '(lambda (x) x)) gives => '(lambda (x) ((x : 0 0)))