Hi! Just to make things more confused, here is another option for occurrence serialisation in JSON, YAML etc.
Use arrays/sequences with two values for things like?occurrences, that way it's compact (same number of characters as "occurrences": "0..5") and almost as readable, but the parser/serializer does more of the job and will even provide the programmer with data type (e.g. string or number) or null. In JSON... "occurrences": [0, 5] ...and YAML... occurrences: [0, 5] The question of how to do with unbounded "*" still remains of course, one could do valid (ugly but compact) JSON like... "occurrences": [0, "*"] On Fri, Nov 11, 2011 at 04:36, Andrew Patterson?<andrewpatto at gmail.com>?wrote: > Why cant' the absence of a value mean unbounded? > occurrences = < ?lower = <2>?> > > Means 2..* Then a JSON like... "occurrences": [2] ... (assuming occurrences are never unbounded in the lower end) or... "occurrences": [2, null] ?...could mean unbounded upwards. I guess asking an API or programming language for the second value (index 1 if starting at 0) of the array will return null in both cases above. Since the short form of 1..1 often is just written as 1 in UML and ER-diagrams, the first style with "occurrences": [1] meaning 1..* should probably be avoided and instead "occurrences": [1, null] should be recommended for 1..* if humans are supposed to read. (And thus using "occurrences": [1, 1] if you mean 1..1 and "occurrences": [0, 0] if you mean 0..0) It looks a bit scary/ugly though, but probably better than [2, "*"] and to check for null is in many programming languages nicer than having to check datatype and possibly string content. On Fri, Nov 11, 2011 at 04:36, Andrew Patterson?<andrewpatto at gmail.com>?wrote: > Also, what about inclusive/exclusive values at either end > of the interval? I know that this isn't an issue for occurence and > cardinality intervals which are always inclusive - but are we proposing that > the representation of normal intervals will not use the same mechanisms > are you are proposing here? What about using?booleans in an?array/sequence? "inclusive": [true, false] ...meaning inclusive in lower but not upper end. But perhaps intervals need a completely different approach. Was that confusing enough? Best regards, Erik Sundvall erik.sundvall at liu.se http://www.imt.liu.se/~erisu/? Tel: +46-13-286733 P.s. Off-topic: If this discussion was rushed and had to be decided in a time-limited face to face meeting we might already have picked the "0..*"-string version and would have hesitated even to consider the above as a possibility if it popped up a few days later. (I am just trying to hint that slow open mail discussions allow more technical ideas to come forward than rushed meetings. Face to face meetings have great value too, but perhaps even more for other things than technical design.)
