bug?

[Mark Evenson]

On 2015/7/26 12:30, Pascal J. Bourguignon wrote:
> 
>> On 24 Jul 2015, at 14:33, Alejandro Zamora Fonseca <terefv at ltu.sld.cu <mailto:terefv at ltu.sld.cu>> wrote:
>>
>> Hi!
>>
>> Just now playing a little with ABCL(1.3.2), I saw some strange behaviour:
>>
>> CL-USER> '(2 . 5)
>> (2 . 5)
>> CL-USER> '(2 . 5 . 5)
>> (2 . 5)
>> CL-USER> (equal '(2 . 5) '(2 . 5 . 5))
>> T
>>
>> while other implementations give me an error when i type '(2 . 5 . 5)
>> it's a bug or ANSI CL allows this?
> 
> 
> Depends.
> 
> ANSI CL specifies the lisp reader in such a way that (2 . 5 . 5) is not a valid syntax.
> However, ANSI CL specifies that implementation may extend the CL language, UNDER THE CONDITION that extensions BE DOCUMENTED.
> 
> Therefore, IF it is written in ABCL documentation that (2 . 5 . x) reads as (2 . 5) 
> THEN it is not a bug, but an ABCL specific extension,
> ELSE it is a conformity bug, it should signal a READER-ERROR (or perhaps just an ERROR).

As far as I can tell, we never intended to extend the reader to accept
such forms, so we'll call this a [bug][395].

If changing this to an error breaks anyone's existing code, please let
us know.

[395]: [http://abcl.org/trac/ticket/395

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