[tex-k] [NTG-pdftex] Bug#458059:

[David Kastrup]

Frank Küster <frank at debian.org> writes:

> There is a configuration variable nest_size level, but it doesn't seem
> to help in this case: The attached file gives an error
>
> ! TeX capacity exceeded, sorry [grouping levels=255].
>
> although my texmf.cnf has nest_size=500.

I find it awfully hard to reliably trigger a semantic nest size
overflow.  The best I have been able to come up with was

dak at lola:~$ tex
This is TeX, Version 3.141592 (Web2C 7.5.6)
**\def\x{\vbox\bgroup x\x}\x
! TeX capacity exceeded, sorry [semantic nest size=500].
<recently read> \bgroup 
                        
\x ->\vbox \bgroup 
                   x\x 
<*> \def\x{\vbox\bgroup x\x}\x
                              
No pages of output.
Transcript written on texput.log.

But this only barely triggers, since 500 is less than 2*255, the
grouping level limit.  And I can't at the moment think of a way to get
more than two semantic nests per grouping level.

Can anybody think of a semantic nest without grouping apart from
unrestricted hmode (which I use above)?

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum