Re: Calling a function with undefined symbol

[Michael Heerdegen]

Emanuel Berg <incal@dataswamp.org> writes:

> >> Yes, but why do you need the "strange value" for that?

Let's call the strange `'''''''''...` values "quote-quine" for now so
that it's easier to talk about them (better than saying "the strange
value" all the time).  I said value_s_ here because there is no unique
quote-quine in the `eq' sense.

> > I chose it because you get an `equal' value when you quote
> > the value (to suggest a wrong track to an answer), and
>
> You do?
>
> (setq print-circle t)
>
> (setq x #1=(quote #1#))
>
> (eq    'x x) ; nil
> (equal 'x x) ; nil
>
> ?

I don't see any place in your code where a quote-quine is quoted.  You
correctly assign a quote-quine to a variable.  But then you only quote
the symbol, not the value, and compare the quote-quine with the symbol
you had bound it to.

IOW: It's a trap!

So how could a correct `equal'ity test of a quote-quine and that
quote-quine quoted be achieved?  This is exercise number 3.


> So the length is 2, but the depth is infinite. IOW: It's a trap!

Yes, this is the correct solution.  Congratulations!

Michael.