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Re: another nit.


What does vector-ref return when someone accesses it beyond a valid index?
Whatever this behavior is, should also be the behavior of assq-ref.

Jon

On 6 Jul 2000, Harvey J. Stein wrote:

> Michael Livshin <mlivshin@bigfoot.com> writes:
> 
>  > I think `assq' is good enough.  millions^Wthousands^Wlots of Lisp
>  > users that live with the convention of returning #f (or nil) when a
>  > key does not exist don't seem to mind much.
> 
> The argument was about assq-ref, not assq.  assq is invertible because
> it returns the list element (a pair) whose car matches the key and #f
> if nothing matches.  So it returns #f iff the key isn't in the list.
> 
> As for assq-ref, I guess it'd be convenient for it to match common
> hashtable interfaces, namely to have an extra optional argument to
> specify what to return if the key isn't found.  It's also not uncommon
> to throw an error if the key isn't found & the optional argument isn't
> supplied.  This would give something for everybody.
> 
> However, given the existence of assq, I don't see the point.  Why not
> just use assq if you need to know whether or not the key is in the
> list?
> 
> -- 
> Harvey Stein
> Bloomberg LP
> hjstein@bfr.co.il
> 


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