[texhax] A problem about \jobname

[geolsoft at mail.ru]

On Thu, Aug 19, 2004 at 07:44:45AM +0100, Robin Fairbairns wrote:
> the code you quote comes from the latex cite package, and is mentioned,
> among many others in the discussion of this issue in
> http://www.tex.ac.uk/cgi-bin/texfaq2html?label=isitanum
> 
> good for oleg, i say, but it would be nice if he had quoted his
> sources...


I agree with your reaction.  In fact, I myself hate when people don't give fair
credit.  But please read below quote from my original message (archived at
http://tug.org/pipermail/tex-eplain/2004-August.txt.gz):

> the following for the checking:
>
>   \def\gobbleminus#1{\ifx-#1\else#1\fi}
>   \def\IsInteger#1{%
>     TT\fi
>     \ifcat_\ifnum9<1\gobbleminus#1 _\else A\fi
>   }
>
> which must be used as
>
>   \if\IsInteger{<subject of test>}%
>     <deal with integer>%
>   \else
>     <deal with non-integer>%
>   \fi
>
> (I adopted these macros from The UK TeX FAQ, http://www.tex.ac.uk/faq).

I did not refer to the cite package as the macro I borrowed, according to the
FAQ, is a generalization of the one used in cite package.

By the way, would not it be useful to document in the FAQ situations when
\IsInteger could fail?  The ones I can think of are:

1. \IsInteger{ {23}} will say it has an integer (i.e., leading spaces and/or one
   level of braces are disregarded, due to the \gobbleminus helper).

2. When `<subject of test>' starts with a number, followed by an `_', followed
   by something else, \IsInteger gives truth, and `something else' followed by
   an `_' gets out into the output.

It has just come to my mind (might be a blunder, I did not do much testing)---it
seems to me that the first problem can be solved by eliminating the call to
\gobbleminus, like this:

  \def\IsInteger#1{%
    TT\fi
    \ifcat_\ifnum9<1\ifx-#1\else#1\fi _\else A\fi
  }

This trades one problem for another---now _trailing_ spaces are disregarded
(i.e., \IsInteger{23 } will give truth), but at least the braces problem is gone
now.  Do you see any problems with this?


Best regards,
Oleg Katsitadze