[texhax] controlling expansion

Lars Madsen daleif at imf.au.dk
Thu Feb 28 16:15:02 CET 2013

And what exactly would you consider empty, is \dosomething{ } empty or not?

/Lars Madsen
Institut for Matematik / Department of Mathematics
Aarhus Universitet / Aarhus University
Mere info: http://au.dk/daleif@imf / More information: http://au.dk/en/daleif@imf

From: texhax [texhax-bounces at tug.org] on behalf of Michael Doob [mdoob at cc.umanitoba.ca]
Sent: 28 February 2013 16:02
To: texhax at tug.org
Subject: Re: [texhax] controlling expansion

On 13-02-28 08:51 AM, Neal H. Walfield wrote:
> I spent some time reading and found a good solution for determining
> whether an argument is empty in David Solomon's Advanced TeXbook:
>    \ifx\empty#1\empty empty \else not empty\fi
> Nice trick!  TeX requires a lot of lateral thinking.

Cute, but what about \empty{\empty}? :-)


Michael Doob                    Telephone: (204) 474-9796
Department of Mathematics       Fax: (204) 474-7606
University of Manitoba          email: Michael_Doob at umanitoba.ca
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