The usage exploits documented features. The interpretation is as follow: noun conj is an adverb. Therefore (+:`*:@.) is an adverb. (+:`*:@.) 2 4 6 is adverb noun and is a syntax error. 0 (+:`*:@.) 2 4 6 is interpreted as (0 (+:`*:@.)) 2 4 6 , wherein (0 (+:`*:@.)) is (+:`*:@.0) and is +:, whence (0 (+:`*:@.)) 2 4 6 <-> +: 2 4 6 <-> 4 8 12 .
----- Original Message ----- From: Ronan Reilly <[EMAIL PROTECTED]> Date: Monday, March 12, 2007 4:30 pm Subject: [Jprogramming] Undocumented(?) feature of @. > Having given my students a simple J assignment that required the > use of @., > some of them came up with solutions that used what appears to be an > undocumented feature of the conjunction: > > As you might expect... > > (+:`*:@.) 2 4 6 > |syntax error > | (+:`*:@.)2 4 6 > > but... > > 0 (+:`*:@.) 2 4 6 > 4 8 12 > > 1 (+:`*:@.) 2 4 6 > 4 16 36 > > It appears that [ is assumed if the rhs of the conjunction is > omitted. Is > this correct or am I missing some subtle J generalisation? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
