Brian,
May I continue the POSIX thread a little more ...
Is there a natural or correct way to represent just time of day, with no
associated date, in the POSIX scheme? Is setting date to 1970-01-01 the
best / only way?
You suggest format(x, tx="GMT") to force POSIX objects to appear as GMT. I
take it that this disables the implementation of 'Daylight Time'? I am
unsure whether 'GMT Standard Time' and 'GMT Daylight Time' are different
time zones or are they both just part of 'GMT' time zone?
GMT means GMT. There is no such thing as `GMT Daylight Time': Windows is
wrong here. There is GMT/UTC and there is BST.
Would it be useful to be able e to be globally set all POSIX objects to
display as, say, 'GMT Standard ' with a 'global' in options() ?
You just set the timezone in use to that. Sys.putenv(TZ="GMT") for me.
I'll look into seeing if there is an easier way.
Finally, I think the that the handling of date-times by POSIX object
warrants several paragraphs in 'An Introduction to R' - or perhaps I'm just
slow on the uptake!
It's too specialized. There will be an article in the next R-news, though.