If I recall correctly (and a quick search isn't finding me anything, but we've discussed this previously in this forum), hooks were a mistake - they were unnecessary cuteness. But, now that we have them, we can't get rid of them - it would break too many things.
That said, here's the dictionary page on trains: http://www.jsoftware.com/help/dictionary/dictf.htm It's all spelled out pretty much right there. Basically: a hook has two verbs a fork has three verbs four verbs can be thought of as a hook and a fork, where the rightmost verb in the hook is that fork. five verbs can be thought of as a pair of forks, where the rightmost verb in the left fork is the three verbs of the right fork. This extends inductively. You can see this by using 9!:3]6 and then forming arbitrary length trains. 9!:2'' 5 9!:3]6 ------------ - (- - (- - (- - (- - (- - -))))) I hope this helps, -- Raul On Mon, Jul 22, 2013 at 3:42 AM, Tobia Conforto <[email protected]> wrote: > Thank you. > > I had tried to do something similar, but I couldn't come up with a decent > ambivalent verb to use. > > Now for the big question. Even-numbered and odd-numbered dyadic trains behave > very differently. Is there a purpose behind this difference? Or is it just a > product of the other rules? > > In my very humble opinion, even-numbered dyadic trains look out of place. > They lose their "dyadicness" early on and expand into a monadic train: > > (x (F e D c B a) y) -: x F (e D c B a) y > > — > Tobia > > > On 22 Jul 2013, at 02:43, Raul Miller wrote: > >> That looks right, to me. >> >> Note that you can test this if you replace := with -: >> >> For example: >> >> x=: 1 >> y=: 2 >> a=:B=:c=:D=:e=:F=: <@,&< >> >> Thanks, >> >> -- >> Raul >> >> >> On Sun, Jul 21, 2013 at 7:53 PM, Tobia Conforto >> <[email protected]> wrote: >>> Hello >>> >>> I'm trying to understand trains of verbs and I came up with this. Can >>> anybody please either confirm it or correct me? >>> >>> Monadic trains: >>> >>> (B a) y := y B (a y) >>> (c B a) y := (c y) B (a y) >>> (D c B a) y := y D (c y) B (a y) >>> (e D c B a) y := (e y) D (c y) B (a y) >>> (F e D c B a) y := y F (e y) D (c y) B (a y) >>> >>> Dyadic trains: >>> >>> x (B a) y := x B ( a y) >>> x (c B a) y := (x c y) B (x a y) >>> x (D c B a) y := x D ( c y) B ( a y) >>> x (e D c B a) y := (x e y) D (x c y) B (x a y) >>> x (F e D c B a) y := x F ( e y) D ( c y) B ( a y) >>> >>> Capped fork in even-numbered dyadic train: >>> >>> x (F e D c B a) y := x F (e y) D (c y) B (a y) >>> x (F e D [: B a) y := x F (e y) D B (a y) >>> x (F [: D c B a) y := x F D (c y) B (a y) >>> x (F [: D [: B a) y := x F D B (a y) >>> >>> Capped fork in odd-numbered dyadic train: >>> >>> x (e D c B a) y := (x e y) D (x c y) B (x a y) >>> x (e D [: B a) y := (x e y) D B (x a y) >>> x ([: D c B a) y := D (x c y) B (x a y) >>> x ([: D [: B a) y := D B (x a y) >>> >>> >>> -Tobia >>> ---------------------------------------------------------------------- >>> 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 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
