From ripley at stats.ox.ac.uk  Wed Aug 31 12:40:42 2005
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Wed, 31 Aug 2005 11:40:42 +0100 (BST)
Subject: [Rd] So-called 'bug' reports PR#8102 and PR#8103
Message-ID: <Pine.LNX.4.61.0508311105430.28816@gannet.stats>

Neither of these have reached me on R-devel (and only PR#8103 is on the 
archive), and they seem to be the same error although neither mentions the 
other.  That's 'odd', to quote one of them.

"EDT" is not a valid POSIX timezone (but, say, EST5EDT is).  R's docs are 
quite clear that what happens with invalid inputs is system-specific. 
(Windows seems often to run home to PST8PDT.)  You can have timezones 
without DST, but not one permanently in DST.

In short, these were user errors compounded by unhelpful error-recovery by 
the OS the users were using.

As to why tm + 3600 and tm + c(0, 1) * 3600 differ: one time is in one 
timezone, but two can be in different timezones so they must be handled 
differently.  This is handled slightly differently in the R-devel version, 
which both the posting guide and the FAQ do ask you to try out (as well as 
consulting the NEWS file which has a relevant entry).

Next time, please show some consideration for those who have to clear up 
after you, and do as we ask in the posting guide and FAQ.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595



[Rd] So-called 'bug' reports PR#8102 and PR#8103
Prof Brian Ripley