Henry Rich <henryhr...@gmail.com> wrote: > I think I agree with all your statements, but you are not responding to > my questions, which will help focus the discussion: > > 1. What is a Dictionary, EXACTLY?
FWIW, I find myself confused by this question. Maybe I am just failing to pick up on an implicit convention here, but an "exact definition" is only precise/unambiguous relative to a given base reality. Case in point, defining a dictionary as a mathematical function from a set of keys to a set of values, is precise and exact in the sense of ZFC, but I suspect it's not particularly useful in this situation. What particular "base reality" is best to define against here? Maybe negative anwsers could help clarify things? - Why is a 2-column inverted table, together with appropriate access idioms, not a dictionary? - HPC folk have been representing trees as cleverly-arranged arrays for years, apparently. Why are tries [0] not dictionaries? I suspect that anwsers might include discussion about specific performance issues. So maybe complexity bounds on operations need to be specified for a sufficiently exact answer? Or maybe J primitives already suffice, but we're simply noting that the appropriate idioms have a really steep learning curve and that we want a more beginner-approachable alternative? Wonder what Roger Hui would say... :/ https://www.jsoftware.com/papers/APLHashingModel.htm [0]:https://en.wikipedia.org/wiki/Trie#Replacing_other_data_structures ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
