Re: () eq () vs () = ()

On 30 September 2011 13:26, G. Ken Holman <gkholman@xxxxxxxxxxxxxxxxxxxx>
wrote:
> At 2011-09-30 12:28 +0100, Andrew Welch wrote:
>>
>> Regarding deep-equal(), the first bullet seems wrong: "If the two
>> sequences are both empty, the function returns true." It's well
>> defined, but doesn't seem to follow the rest of the spec where one
>> side is ().  I wonder if it could easily be as well defined as
>> 'false'.
>
> But it is consistent with the requirement for the length of the two
> sequences being the same (the second bullet says if the lengths are
> different then return false()), and the third bullet doesn't come into play
> because the lengths are zero.
>
> So, I think the length property makes a good case for them being equal and
> returning true().

Hmm the length thing is just a quick way of determining if they aren't
equal (without the cost of having to compare any values).

If () = () is false, then it's intuitive (to me) that deep-equal((),
()) is also false.  The one liner saying that it should be true just
seems like it could easily say false.




--
Andrew Welch
http://andrewjwelch.com