Re: [Chicken-users] Question regarding "length"

[Kon Lovett]

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On May 29, 2006, at 1:51 PM, Abdulaziz Ghuloum wrote:

> Greetings,
>
> I sent this question to the list last week but it complained about me
> not being a subscriber.  I'll assume it did not get through, so here
> it is again:
>
> Looking at the definition of length in chicken, I noticed that it
> detects neither circularities nor improper lists.  For example:
> (length '(1 2 . 3)) => 2
> and
> (length (let ((x (cons 1 2))) (set-cdr! x x) x)) => infinite loop.
>
> I'm wondering if this is a bug, or a design decision.  And if it
> is by design (my guess), I would like to know the rationale behind it.

Speed probably. I don't think R5RS specifies behavior for improper or  
circular lists. Use SRFI-1 length+, proper-list?, circular-list?, etc.

What is the list length of (1 . 2) anyway? Only 1 makes sense.

> Thanks.
>
> Aziz,,,
>
>
>
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> Chicken-users mailing list
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