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From: dje@lanl.gov (debi erpenbeck)
Newsgroups: comp.text.tex
Subject: Testing for empty arguments
Message-ID: <23072@lanl.gov>
Date: 2 May 91 15:15:30 GMT
Organization: Los Alamos Natl Lab, Los Alamos, N.M.
Lines: 17

I've been trying (unsuccessfully) to get the following code to print
"Arg1 is empty". Can someone tell me how to do this?

\def\macro#1#2{%
\ifcat#1=\empty
	\message{Arg1 is empty}%
\else
	\message{Arg1 is not empty}%
\fi
}

\macro{}{}
\bye

\ifx#1=\empty
\if#1=\empty
\ifcat#1=\empty