Re: 5.2 work3 manual

[Gavin Wraith <gavin@...>]

In message <20100519142632.GC30640@inf.puc-rio.br> you wrote:

> > My thinking was that if t[1] is not defined, then the array part of
> > t is {} - I had believed that # should depend only on the array
> > part of a table.
>
> What do you mean by "the array part of a table"?

That a table x (if constructed) would be the array part of a table t if:

  define n to be the greatest integer for which t has keys
  1,2, ... ,n or zero if t has no such keys;
  then x has keys 1,2, ... ,n and x[i] == t[i] has the value true for
  i = 1,2, ... ,n or else x is {}.

What I mean by "has keys" troubles me in the light of the fact
that if x = { } and y = { nil } then x[1] == y[1] is true.
Yet x has no keys, whereas y has 1 as a key. So there appears to
be no way semantic way of testing "having the same keys" -
one is appealing to what is happening "under the hood".

Am I making sense? Perhaps I am just airing my own confusions about
what is old news to others. In which case apologies for the noise.

-- 
Gavin Wraith (gavin@wra1th.plus.com)
Home page: http://www.wra1th.plus.com/