A puzzle with TeX \ifnum

[Isaiah Shavitt]

-----------------------------------------------------------------------------
This is the PSTricks mailing list, devoted to discussions about computational
graphics in (La)TeX using the PSTricks package from Timothy van Zandt.
For help using this mailing list, see instructions at the end of message.
-----------------------------------------------------------------------------

Can somebody tell me why

	\ifnum\ylen>0\else\pssetlength{\ylen}{-\ylen}\fi

works (forcing \ylen to be positive), while

	\ifnum\ylen<0 \pssetlength{\ylen}{-\ylen}\fi

does not?  It does not work even if I put \relax after the <0, 
or put the \pssetlength command in braces, or try a few other 
variations.  The \pssetlength command is just not executed.
Or is there a better way to get the absolute value of \ylen 
without using PS code?

--------------------------------------------------------------------------
Isaiah Shavitt
Professor Emeritus
Department of Chemistry           Telephone: 614-292-1668
The Ohio State University         Fax:       614-292-1685
Columbus, OH 43210-1185           E-mail: shavitt at chemistry.ohio-state.edu
--------------------------------------------------------------------------

-----------------------------------------------------------------------------
The list interface (subscription, information, access to the archives) is on:
http://www.tug.org/cgi-bin/lwgate/pstricks
Otherway to unsubscribe, send mail to pstricks-request at mail.tug.org
with a blank subject and in body the line unsubscribe <email-address>
-----------------------------------------------------------------------------