[tz] Extended data format

[Ian Abbott]

On 2013-09-05 17:52, Andy Lipscomb wrote:
> "I guess such =zone references should refer to a zone earlier in the
> same file to keep things simple, i.e. no forward or external
> references."
>
> Not an absolute logical necessity, but certainly a safe way to do
> things. It does have implications in the design of the extended
> files, in that they would need to be supersets of the basic files,
> not supplemental files used in conjunction with them. In the
> alternative, a limited form of import could be allowed in that a file
> named (for exampile) "kalimdor-extended" would be allowed to
> reference the zones of the file "kalimdor" as well as the ones it
> contains itself.

I suppose there's no harm in allowing external references as long as 
those are parsed first, treating the concatenation of the files (or a 
subset of the files, e.g. excluding the "extended" zones) as "one big 
file".  This means you could only run zic on a self-consistent list of 
files ordered to not have no forward references.

Another possibility would be to have an "Include" directive containing a 
relative pathname (relative to the file containing the "Include" 
directive) to another file.  Then "kalimdor-extended" could contain the 
line:

Include kalimdor

to include the non-extended zones before it defines the extended zones. 
  Then zic could be run on either kalimdor or kalimdor-extended, but not 
both, since the latter includes the former automatically.

-- 
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