Carnival Sunday in Brazil

[Robert Elz]

    Date:        Mon, 22 Sep 2008 10:18:57 -0500 (CDT)
    From:        Dave Rolsky <autarch at urth.org>
    Message-ID:  <alpine.DEB.0.9999.0809221016420.31443 at urth.org>

  | Those of us who write our own parsers will thank you for not changing the 
  | format with weird little special cases ;)

That wouldn't be changing the format.   If you're parsing the tz
format files (the text input, rather than the zic output) and you're
not handling the exception scripts, then you're not parsing the tz
format, just a rough approximation.  This stuff isn't new, it has
been there forever, and was once actively used (though as Arthur said, not
for a while now...)

That isn't to say that I think it is a good idea to do it this way.
A script to figure out Brazillian carnival dates (which from what I saw
just means figure out Easter, and subtract) might be useful for other
purposes, but using it here isn't really warranted I suspect.

Even less would be embedding code into localtime for this (that is,
extending the compiled zoneinfo file format to add some extra magic).

Recall, we're dealing with Summer time dates here - one of those things
that the world's governments fiddle with for almost undetectable
reasons, planning something with an expectation that it might be useful
for hundreds of years seems a little over optimistic.

Just stick in the dates that are calculated now, it sees to me that
the chances that the rules will remain the same up to 2030 or something
are close to zero anyway - that is, by the time we'd need to be doing
more, we probably won't be doing the same thing anyway.

kre