On Thu, 2015-06-11 at 14:45 +0100, Gordon Sim wrote: > On 06/11/2015 01:54 PM, aconway wrote: > > On Thu, 2015-06-11 at 13:40 +0100, Gordon Sim wrote: > > > If a name field is populated with an empty string, that to me is > > > the > > > same as not supplying a name. An empty string is a legal > > > encoding, > > > but > > > in my view it does not supply a value at all. (It is not like say > > > 0 > > > which may be the default but is clearly a value in its own > > > right). > > > > > > > It is exactly like 0, a perfectly legal value that is often abused > > to > > mean something special. > > It is treated as meaning 'empty' i.e. 'there is nothing here'. I > don't > consider that abuse myself. > If a string is a sequence of chars, the > empty string is not a sequence of chars, there are no chars specified > in > sequence, therefore it clearly is 'special'. The distinction between > an > empty string and null is an artificial one and in my view anything > for > that relies on that difference to convey something logically > significant > is poorly designed. >
0 does not mean "there is no number here", even though numbers are for counting things and 0 means there are no things. Similarly "" does not mean "there is no string here" it means there is a string and it is empty. "Abuse" was a poor choice of word - it is fine to assign special meanings to 0, negative numbers, "" etc. but you have to *say* that in the API or spec. The spec could have said "a delivery tag is a non -empty binary" and I would agree with you, but it just says "a delivery tag is a binary." I also agree that "" is a terrible choice of delivery tag and we shouldn't ever *use* it (precisely because other people may not make the distinction) but for interop purposes I think we have to accept it. Be strict with what you send forgiving with what you receive. > In any case there is no harm in handling an empty string as a valid > delivery tag (as long as it is unique). I have no objection to that. > > The only part I personally consider important is that proton-c > doesn't > crash. Agreed.
