[tz] zdump new option -i for easier-to-review output

Jon Skeet skeet at pobox.com
Tue Jun 7 08:53:40 UTC 2016

I'm totally in favour of the pragmatic approach of assuming there isn't
crazy data. Let's try to design the format to accomplish what we need it to
- which to my mind doesn't include years earlier than 1800 or later than
3000 (and probably a narrower range than that - I currently only check up
to 2035, but that makes me somewhat nervous).

I'd rather have something that does what it's designed for well and doesn't
work for tasks it's not designed for than something that copes with
everything, but does so in a mediocre way.

I quite like Tim's padding idea overall, although I'd stlil argue for
colons in offsets (RFC5322 uses a horrible format in general; I see no
reason to copy mistakes of the past) and "d" instead of "a positive
integer" to indicate daylight. (My goal is for this to capture all the
relevant information from the original data text files, but the
implementation details of is_dst fall outside that scope IMO. That's not
part of the source data.)

I'm still fine with the idea of transforming some non-ideal-to-me format
from zdump into a more canonical format in a simple way though.


On 7 June 2016 at 09:44, Paul Eggert <eggert at cs.ucla.edu> wrote:

> Tim Parenti wrote:
> I realize the goal may be to have a single canonical format, but perhaps
>> this could be made conditional on a -z option?
> Yes, or some such option like that. I was thinking more of a strftime-like
> format in which one could specify UT vs local time.
> Just to throw in a potential middle-of-the-road option, would it make sense
>> to space-pad the datetime and offset values instead?
> I thought of doing that, but found that it would be a pain, since the
> amount of padding would be system-dependent. Every field whose extrema
> depend on machine integer size (the year, the UT offset) would have a width
> that would depend on the current machine architecture, and this would mean
> zdump -i would generate different outputs on different machine
> architectures. Plus, there would be a lot of spaces before the year and the
> UT offsets.
> Alternatively, zdump could look at all output to be generated for this
> particular zdump run, compute the maximum width needed for the run, and use
> that width. But this would mean that 'zdump -i A; zdump -i B' would not
> necessarily output the same thing as 'zdump -i A B', which would not be
> good at all.
> Alternatively, zdump could not bother to align outlandish years outside
> the range -999,9999 or outlandish UT offsets that are more than 100 hours
> away from UT. Something like that might work, I suppose, though we'd
> probably still get bug reports from compulsive aligners wondering why the
> outlandish cases aren't aligned properly, or why there's all that white
> space in the columns.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mm.icann.org/pipermail/tz/attachments/20160607/466472a1/attachment.htm>

More information about the tz mailing list