Re: arithmetic

[Patrice Dumas]

On Thu, Aug 15, 2013 at 06:22:09PM +0000, Karl Berry wrote:
> Patrice,
> 
> Was this change in node pointer arithmetic unintentional?
> At least I don't recall discussing it.

I recall vaguely discussing something about node arithmetics when I
implemented info in texi2html.  I didn't found anything in my mails,
though.

> Can we go back to the original arithmetic?  And perhaps we should
> document the specifics in the Info spec appendix.

This is already done, in 'Info Format: Indirect Tag Table', unless I am
missing something.

In fact there is a sentence there that certainly refers to our
discussion:

   Unfortunately, Info-creating programs such as 'makeinfo' have not
 always implemented these rules perfectly, due to various bugs and
 oversights.  Therefore, robust Info viewers should fall back to
 searching "nearby" the given position for a node, instead of just giving
 up if the position is not perfectly at a node beginning.

The text here do not match the bug report, as it seems that the node
position is relative to the subfile including the preamble.  In fact I
don't really understand the bug report, but it seems not to be correct,
or texi2any do not follow the specification, which would be strange,
except if there is a bug.

However, seeing the output of the test file in the emacs bugreport, I
think I spot a bug, as the text that appears before the first node, that
should be counted in the preamble does not seems to be counted.

> Makeinfo 5.0 changes in arithmetic of node positions in the tag table
> makes Info files with the summary segment longer than a thousand characters
> unreadable by the Emacs Info reader.
> 
> Makeinfo 4.13 produced the character positions of indirect subfiles
> relative to the beginning of the first node, but Makeinfo 5.0 produces the
> positions relative to the beginning of the subfile.  The Emacs Info reader
> fails when the distance between the beginning of the subfile and
> the beginning of its first node is longer than a thousand characters.

-- 
Pat