[texhax] Finding blank argument to macro
Uwe Lueck
uwe.lueck at web.de
Wed Jun 30 12:09:23 CEST 2010
Jim Diamond <Jim.Diamond at acadiau.ca>, 27.05.2010 13:43:48:
> On Thu, May 27, 2010 at 07:17 (-0400), Michael Barr wrote:
>> Here is a fragment of a macro I use to find if an argument is empty:
>
>> \setbox0\hbox{$#9$}%
>> \ifdim \wd0=0pt%
>> %%%%%%%% omitted what you do if arg empty
>> \else
>> %%%%%%%% omitted what you do if not
>> \if
>
> Hmmm... what if #9 is
> \hbox to 0 pt{blah \hss}
> ?
... and even: If #9 contains (working) assignments only, it will create an \hbox of zero width, so this macro would consider #9 empty. So #9 could be the content of a macro package, e.g., latex.ltx (unless something) ... Is latex.ltx empty?
Cheers,
Uwe.
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