I regard cap as a brilliant invention, analagous to the invention of zero. "Does nothing" cap is analagous to "Adds nothing" zero. It may help you to read cap in trains as "the ... of ...", eg
[: %: [: +/ *: is the square root of the sum of squares. --Kip Murray On Sunday, February 15, 2015, Jose Mario Quintana < [email protected]> wrote: > I enjoy decapitating capped forks in a flash using one of my favorite > wicked adverbs (decap), > > ( NoProblem=. see f.decap ) > i.@:[ +/ i.@:(#~) > > 3 NoProblem 2 > 0 1 2 > 3 4 5 > 6 7 8 > > 1 2 3 > 4 5 6 > 7 8 9 > > 2 3 4 > 5 6 7 > 8 9 10 > > Decap replaces the form ([: u v) by (u@:v). If for whatever reason one > wants to avoid @: in favor of @ (and ") then the form (u@:v) could always > be replaced by (u@v”_), > > 3 (i.@["_ +/ i.@(#~)"_) 2 > 0 1 2 > 3 4 5 > 6 7 8 > > 1 2 3 > 4 5 6 > 7 8 9 > > 2 3 4 > 5 6 7 > 8 9 10 > > Sometimes one can get away by simply replacing @: by @, > > 3 (i.@[ +/ i.@(#~) ) 2 > 0 1 2 > 3 4 5 > 6 7 8 > > 1 2 3 > 4 5 6 > 7 8 9 > > 2 3 4 > 5 6 7 > 8 9 10 > > By the way, when the meaning of an expression is undefined; for example, > in, > > `/ > |syntax error > | `/ > > An enlighten person could modify the official interpreted and assign a new, > or an ancient, meaning to that form (the conjunction adverb form in the > example above) extending the current J language. However, in your > sentence: > > [:>:i.4 > |domain error > | [:>:i.4 > > that is not the case. So, either the monadic definition of [: would have > to changed (and most likely someone's existing code would brake) or our > beloved sophisticated simple parsing rules would have to be alter (and the > sky would fall). > > Thus, "If the hill will not come to Mahomet, Mahomet will go to the hill" > comes to mind. > > > > > On Fri, Feb 13, 2015 at 5:17 PM, Linda Alvord <[email protected] > <javascript:;>> > wrote: > > > Brian, I like 9!: combinaions. Is it true that you can always remove [: > > from > > a tacit monadic function? > > > > Also, it doesn't seem to be possible to remove all of them from a dyadic > > verb. Here's some examples from code run in a terminal: > > > > 9!:3]5 > > see=: 13 :'(i.x)+/i.y#x' > > 3 see 2 > > 0 1 2 > > 3 4 5 > > 6 7 8 > > > > 1 2 3 > > 4 5 6 > > 7 8 9 > > > > 2 3 4 > > 5 6 7 > > 8 9 10 > > see > > ([: i. [) +/ [: i. #~ > > 9!:3]5 > > cbB=: 13 :'<"0@>:@i.y' > > pairs=: 13 :'(>:@i. x),"0/>:@i. y' > > countB =: <@cb"1@pairs > > > > cbB > > <"0@>:@i. > > pairs > > ([: >:@i. [) ,"0/ [: >:@i. ] > > countB > > <@cb"1@pairs > > > > Linda > > > > > > -----Original Message----- > > From: [email protected] <javascript:;> > > [mailto:[email protected] <javascript:;>] On > Behalf Of Brian > > Schott > > Sent: Friday, February 13, 2015 2:34 PM > > To: Programming forum > > Subject: Re: [Jprogramming] Source of frustration > > > > Raul, > > > > Yes, thanks. > > > > On Fri, Feb 13, 2015 at 10:06 AM, Raul Miller <[email protected] > <javascript:;>> > > wrote: > > > > > I think you mean "tree representation" where you wrote "linear > > > representation". > > > > > > -- > > (B=) > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm -- Sent from Gmail Mobile ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
