It's because the rank of = is 0. If you understand why (0$0) + (0$0) produces an empty result, you can use the same reasoning to explain (0$0) = (0$0) .
Similarly, 1 1 = 1 1 1 1 You are performing a comparison between atoms. To compare two entire operands for equality, use -: which has infinite rank. Henry Rich > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Tracy Harms > Sent: Thursday, April 05, 2007 11:24 PM > To: [email protected] > Subject: [Jgeneral] null comparison > > I recognize (from experimentation) that testing > equality between two null values results in a null > value. > > ($0)=>a: > > #($0)=(>a:) > 0 > ''='' > > ''=0{a. > > > What I have not found is documentation of that fact, > nor explanations of the design choices that led this > to be the case. > > Tracy Harms > > > > ______________________________________________________________ > ______________________ > Expecting? Get great news right away with email Auto-Check. > Try the Yahoo! Mail Beta. > http://advision.webevents.yahoo.com/mailbeta/newmail_tools.html > ---------------------------------------------------------------------- > For information about J forums see > http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
