[tz] [PROPOSED] Rename internal identifiers to match RFC 8536

[Michael H Deckers]

On 2019-06-16 19:14, Paul Eggert wrote:

> Internet RFC 8536 uses names that differ a bit from the names
> historically used in tzdb.  The RFC uses "utoff" instead of
> "gmtoff" for UT (GMT) offsets, and "desigidx" instead of "abbrind"
> for designator (abbreviation) indexes.  Going forward it’s better
> to stick with the RFC terminology in internal identifiers.


     The "GMTOFF" field in tzdb input files is
     related to, but certainly not the same, as the
     UTOFF field in TZif output files. Using the same
     identifier for both fields may therefore be seen
     not to be very helpful; such cases are called "polysemy"
     in some standardization circles. If the "GMTOFF"
     field is going to be renamed then the new name
     should differ from names of (related but) different
     entities; 'STDOFF' would be a better choice in my
     opinion.

     Of course, "internal" identifiers are not relevant
     for the semantics of tzdb data; their choice is a
     purely pragmatic issue. Changing one of them
     therefore must be considered for its pragmatic
     utility which I cannot fully estimate.

     Michael Deckers.