[texhax] TeX Frequently Asked Questions -- question label "gethelp"

[Oleg Katsitadze]

Hi Steffen,

On Fri, May 02, 2008 at 09:50:10AM +0100, Steffen van Bakel wrote:
> how can you automatically generate 
> recursive structures that you want to match against (in the functional 
> programming style) if not by using \bgroup and \egroup?

I'm not sure what you mean.  Why not use { and } ?  Can you provide an
example of what you want to achieve?

> And they are both 
> 'let' to { and } ... but I understand they are not the same.

Yes, for argument delimiters, TeX searches for the tokens { and }
(with respective category codes, of course).

> Can you suggest a way around this?

Maybe, if I can understand what you want :).

> What's puzzling me is that even the last alternative goes wrong.  Following 
> your argument, should TeX not complain about the missing "\end{mygroup}" 
> when it closes on the first ")"?

Not really.  "\end{mygroup}" is not even a primitive, so TeX does not
give it any special treatment -- as far as TeX cares, it's just some
control sequence.

Best,
Oleg