Knuth=. &* NB. (adv) up=. &1 NB. (adv) 2x Knuth up up 4 5 65536 2003529930406846464979072351560255750447825475569751419265016973710894059556311453089506130880933348101038234342907263181822949382118812668869506364761547029165041871916351587966347219442930927982084309104855990570159318959639524863372367203002916969...
See, [Jprogramming] Fwd: Hello all! http://www.jsoftware.com/pipermail/programming/2015-February/041095.html On Tue, Sep 18, 2018 at 10:58 AM, Raul Miller <[email protected]> wrote: > Note that the grammar of this up-arrow operator conflicts with J's grammar. > > So you'll need at least one other word in a J sentence that deals with > this. > > Also, 'u' is a name that probably should be reserved for explicit > adverbs and conjunctions (unless you know how J treats something named > u different from most other names and you are ok with dealing with > your audience in the context of those issues). > > In other words probably either: > > knuth 2 up up up up 3 > > or > > 2 knuth up up up up 3 > > That said, if you are willing to use actual numbers to distinguish > between these up counts, that additional word becomes a number, and > you could do it like this > > 2 (4 up) 3 > > (And you could skip the parenthesis if either the 2 or the 4 was > represented by a name rather than a value.) > > Then again, if you didn't care about vector arguments (Knuth > apparently didn't), you could do it like > > up 2 4 3 > > or any of a variety of other arrangements... > > FYI, > > -- > Raul > > On Tue, Sep 18, 2018 at 2:40 AM Skip Cave <[email protected]> wrote: > > > > How would a J programmer build a verb that would emulate Knuth's up-arrow > > notation <https://goo.gl/7pCZKW>? (https://goo.gl/7pCZKW). Tacit & > explicit > > versions would be nice. > > > > Examples - assuming the verb 'u' is the up-arrow: > > > > 2 u 4 = 16 > > 2 u u 4 = 65536 > > 2 u u u 3 = 65536 > > 3 u u 2 = 27 > > 3 u u 3 = 7,625,597,484,987 > > > > Skip > > > > Skip Cave > > Cave Consulting LLC > > ---------------------------------------------------------------------- > > 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
