On 5 September 2013 13:15, Paul Eggert <eggert@cs.ucla.edu> wrote:
Stephen Colebourne wrote:
Right now we have three things: - Zone entries - active Link entries, for locations that happen to have the entire local time history of another zone - inactive Link entries, that used to have meaning but are no longer favoured (the backward file)
It's not that simple. We also have aliases in the non-backward files. Two examples are 'Europe/Nicosia' and 'GMT'. I don't see why these names should be considered canonical; although they are active link entries, they are not for differing locations.
My primary concern is ensuring that the backward file is removable - ie. no other files contain the "inactive" backward Link entries. Its this that I want to see documented more than anything else. Beyond that, I think consumers will (and already do) treat the backward file as a source of canonicalization, simply as a result of the above. I think that the ability to use it as such should be documented, but I can live with the minimal change proposed in the paragraph above, for example: "The file 'backward' consists of Link entries mapping two names. These are typically interpretted as a link to a modern name from an older name. If the data set is used with the 'backward' file file excluded, then it must remain logical and complete." Stephen