Newsgroups: comp.lang.apl
Path: watmath!watserv1!torn!utcsri!rpi!zaphod.mps.ohio-state.edu!caen!uunet!trirex!root
From: taff@kate (Tom Affinito)
Subject: Question On Verb Rank
Message-ID: <1992Jul23.142521.12231@Trirex.COM>
Sender: root@Trirex.COM (Operator)
Reply-To: trirex!taff@uunet.uu.net
Organization: Trirex Systems Inc.
Distribution: na
Date: Thu, 23 Jul 1992 14:25:21 GMT
Lines: 21

I'm trying to get the verb rank idea under my belt, but I'm having some  
trouble.  Starting with what used to be called the "scalar functions" in  
APL, I notice that + has a rank of (_ 0 0).  I would have thought that +  
would be (0 0 0), in that it applies to scalars monadically and  
dyadically.  I understand how , has a monadic rank of _ but not why + does  
too.  Similarly, why does j. and many others have a monadic rank of _ ?

I am using J Dictionary Version 4, and my understanding of verb rank is  
coming through particular attention to the last paragraph on page 3 and  
its continuation on page 4.  I believe that verb rank is supposed to  
represent the natural shape of the verb's arguments, and that higher  
dimension data will get automatically sliced by the verb into units of the  
verb's rank.  Since + always applies to individual numbers and extends  
across lists and tables, I would believe that + should monadically have a  
rank of 0.

Can anyone offer guidance on this point?

Thanks!
Tom Affinito
trirex!taff@uunet.uu.net
