Connecting two threads -- Ian wrote this here: http://jsoftware.com/pipermail/programming/2014-January/034769.html
> Thus, in the first year of learning J, I unconsciously conjectured Rank > didn't matter -- for most purposes. You could intuit most problems, ones > that don't emerge much for rank 3 arrays or less. In a lifetime of APL I'd > got away without bothering my head about verb rank. This has been my experience as well in my first year. On Fri, Jan 24, 2014 at 9:55 AM, Raul Miller <[email protected]> wrote: > Looking at your current nuvoc page, I see 22 distinct "ranks". The > most common rank entries are _ _ _ (27 of those) and 0 0 0 (26 of > those). Actual numeric values are limited to 0, 1, 2 and _. and there > are also a variety of abstract values (mv, mu, lv, rv, lu, ru). > > So one observation is that the casual user will not understand that > 'mv' means "the rank of the monadic definition of verb argument v". I think I understand the simple case of rank (at the wikipedia page level[1]). I like the suggestion on somehow clarifying the differences between the 22 possibilities. I also wonder if something really direct "verb rank matters most in the following situations..." would be helpful. If it's mostly rank 4+ arrays, then the complexity of the different cases may not be encountered too frequently. This quote comes to mind: http://www.jsoftware.com/papers/perlis78.htm In APL, what flashes through your mind is a cascade of operations: chasing data through arrays, out of the other end of which come — limping and bruised, you know — seven numbers. After having built up arrays of rank eight and coming perilously close to a workspace full out from the other end comes these seven numbers — and they’re pulled out almost painfully — and you say to yourself, “My God, that’s wonderful! That’s a mechanism!” If that's what those 22 cases are intended to support, I and many other beginners to APL may have a long journey to go before it matters. Beginners to J with an APL background are likely a different story. Is NuVoc targeted more so at either one? [1] - http://en.wikipedia.org/wiki/Rank_(J_programming_language) ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
