Thanks David, That's certainly one to put in my toolbox. So nice (and common) I'd almost expect it in the standard library. Learned something new today :)
Best regards, Jan-Pieter On Thu, 16 Feb 2023, 18:28 David Lambert, <b49p23t...@gmail.com> wrote: > Of the new modifier trains, I've found ^:^:_ as "while". A simple test > code: increment while less than 8. (With some errors one need kill the > j session.) > > >: (^:^:_) (<&8) 2 > > 8 > > While=: ^:^:_ > > u. While v. > u.^:v.^:_ > > > Date: Wed, 15 Feb 2023 13:12:37 +0100 > > From: Jan-Pieter Jacobs<janpieter.jac...@gmail.com> > > To:programm...@jsoftware.com > > Subject: Re: [Jprogramming] Atop parsing > > Message-ID: > > < > cans99cyu9dmv0kgq+sh4dtvxiueqvcoz_if5iwzw_cvuhh4...@mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > The reason it's hard to find anything else on modifier trains is that > they > > have been removed from the language a long time ago (with j501 in 2002, > > apparently), and only reintroduced recently with j903. > > > > Before the reintroduction, the only modifier trains were bidents: > > - partially applied conjunctions, yielding adverbs; and > > - chained adverbs, being applied to their left argument in order. > > They were left over because they are simple, intuitive and easy to > remember > > (guessing here, as I wasn't around in the J scene yet). > > These are explained well inhttps:// > www.jsoftware.com/help/learning/15.htm . > > The adverbs each and every defined in the standard library library are > > useful examples of the first kind of bidents: > > type&.<'each' > > adverb > > each > > &.> > > > > The rabbit hole of general modifier trains is deep: they are not > completely > > intuitive (at least to me) and require a thorough understanding of the > > parsing and execution in J, especially when chaining more than three. > They > > are also not indispensable, as you can write explicit conjunctions and > > adverbs to do anything such tacit modifiers would do. I have yet to find > a > > useful, non-trivial purpose for them... Of course, feel free to use them > if > > you like the challenge, but there are far more important areas to get to > > know in J, like rank. Or all the wonderful labs (in the menu, help > > studio > >> labs). > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
