[Tugindia] token from a control sequence

Dr. Dinesh Karia tugindia@tug.org
Wed, 30 Oct 2002 11:57:07 +0530


Dear all,

    This is yet another mail in sequel of understanding \TeX | \LaTeX.

As TTB (The TeX Book) says

********Excerpt from TTB********

If \TeX\ sees an escape character (category 0) in any state, it
scans the entire ^{control sequence} name as follows. (a)~If there are no
more characters in the line, the name is empty (like |\csname\endcsname|).
^^{null control sequence} ^^{csname endcsname}
Otherwise (b)~if the next character is not of category~11 (letter), the
name consists of that single symbol. Otherwise (c)~the name consists of all
letters beginning with the current one and ending just before the first
nonletter, or at the end of the line. This name becomes a control sequence
token. \TeX\ goes into state~$S$ in case~(c), or in case~(b) with respect
to a character of category~10 (space); otherwise \TeX\ goes into state~$M$.

********Excerpt from TTB over ********


Que: Now according to (b) and (c), it should stop when it encounters @ in
the control sequence. On the other hand however, it also says that all the
internal or private variables (and the standard constants like \@ne, \m@th,
\count@) contains the character @. Is this not contradicting?

It seems that when any control sequence containing @ is used, the @ should
have been changed to category 11. But when I saw various class and
stylefiles, I could never trace out when the category of @ is changed. Can
anybody help understanding this concept?



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\meaning\enjoy
Que: I want to make a slideshow that uses Accrobat Reader but I am not sure
if the user will have AR or not. What should I do?

Ans: Simple! Put, on the very first slide of your show, the URL from which
one can get AR!!!

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