[ruby-core:23057] Re: Ruby Time

In article <[e-mail]>,
  valodzka <[e-mail]> writes:

>> > Olson tz database uses 64 bit representation independently from time_t
>> > size.
>>
>> My Debian Etch (i386) system uses TZif format (not TZif2 format).
>>
>> % strings -a /usr/share/zoneinfo/Asia/Tokyo|head -1
>> TZif
>>
>> Is this file 64 bit representation?
>
> Nope. Debian is really stable system.
>
>> > Unfortunatly I haven't, and this is the biggest problem.
>>
>> I wrote a patch:http://www.a-k-r.org/tmp/ruby-big-time.patch
>>
>
>> Yes.  This is what I said at the last sentence of
>> [ruby-core:22949].
>> But why you add a timezone at first place?
>>
>> Assume a web based messaging system.
>> Each user has timezone preference.
>>
>> User A sends a message to user B and C.
>> User B see the date of the message in the timezone of B.
>> User C see the date of the message in the timezone of C.
>>
>> In this scenario, timezone should be used at constructing
>> the page for B and C.
>>
>> The timezone of A is not used.  No need to store the
>> timezone of A in a Time object.
>>
>> It is enough to set a timezone at the last place.
>> After the last place, Time object is used just for
>> formatted and embedded for a presentation form.
>> I.e. time calculations (Time#+, etc.) are not used after the
>> timezone is set.  So time offset is enough for this purpose.
>
> Okay, may be you are right. But I haven't understood purpose of your
> patch. Can you give an example of problem which has been solved by it?

My patch just change internal representation to relax the
representable range.

With the patch:

  % ./ruby -e 'p Time.utc(2**100)'
  1267650600228229401496703205376-01-01 00:00:00 UTC

Without the patch:

  % ruby -e 'p Time.utc(2**100)'  
  -e:1:in `utc': bignum too big to convert into `long' (RangeError)
          from -e:1:in `<main>'

No timezone/offset related extension yet.

I think Time.mktime should take optional 8th argument,
offset, as
Time.mktime(year, mon, mday, hour, min, sec, usec, offset).

offset can be a number or a string such as "+09:00".
:std and :dst may also be accepted for tm_isdst for
mktime().

If people needs timezone abbreviations really, 9th argument
may be extended.  It is just for Time#zone, etc.  Not used
for time calicurations.
-- 
Tanaka Akira