On Thu, Nov 14, 2019 at 3:11 AM Andrew <ericpan...@gmail.com> wrote:
> I have this:
>
> (define (related? a1 a2)
> (if (equal? a1 a2)
> true
> (related? (member (rest ("proc that calls list" a1)) (rest ("proc
> that calls list" a2)))
> (member a1 ("proc that calls list" a2))))))
>
I can't make sense of the last 2 lines. `(member x l)` returns a sublist of
l starting with x if l contains x, otherwise false. If your two calls to
`member` returns #f, then the next call to related? will compare (equal? #f
#f) and thus return #t, which is not what you want.
Furthermore, in your first call to `member`, the first argument you pass is
a list, which is suspicious.
To get a better sense of what is happening, a general advice (works for
all programming languages) is to print the values of your variables, for
example:
(define (related? a1 a2)
(displayln (list 'a1: a1 'a2: a2))
(if (equal? a1 a2)
true
(related? (member (rest ("proc that calls list" a1))
(rest ("proc that calls list" a2)))
(member a1 ("proc that calls list" a2)))))
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