[cdr-discuss] What about CDR 3, then?

[Pascal Costanza]

On 6 Dec 2006, at 17:11, Nikodemus Siivola wrote:

> Pascal Costanza <pc at p-cos.net> writes:
>
>> OK, apparently my wording wasn't very clear. What I meant is this:
>> Actually just because these functions are defined only on lists and
>> vectors _and_ the only kinds of sequences you can create in ANSI CL
>> are lists and vectors, everything is well-specified.
>
> Not quite. Implementations are allowed to have eg.
>
>  MAKE-FOO-SEQUENCE
>
> that returns objects of type SEQUENCE, which are neither vectors nor
> lists, and all functions defined to work on sequences are required to
> work on such objects.
>
> The upshot is that while a portable program cannot construct a
> non-portable sequence object, eg. portable libraries should be written
> to deal with generic sequences as well -- and this is just plain ANSI.
>
> Granted, no such extended sequences have traditionally exited, but
> that is not what the spec says.

OK, good point.


Pascal

-- 
Pascal Costanza, mailto:pc at p-cos.net, http://p-cos.net
Vrije Universiteit Brussel, Programming Technology Lab
Pleinlaan 2, B-1050 Brussel, Belgium