RFC2: Date/Time proposal

[Charles Day]

On Fri, Jul 18, 2008 at 11:28 PM, Nathan Buchanan <nbinont at gmail.com> wrote:

>
>
> On 7/19/08, Charles Day <cedayiv at gmail.com> wrote:
>>
>> I'm going to go ahead and throw out another proposal for comments. I'm
>> calling this RFC2. Unless specifically stated, all that follows refers to
>> transaction posting dates and times only.
>>
>> Since to my knowledge the feature of having a "time zone per account" has
>> not actually been requested by any user, I'm going to leave that
>> completely
>> out of this proposal. However, if there ever was a need for that feature
>> in
>> the future, this proposal is readily extensible to support that.
>
>
>
> First off, I agree that for most (maybe all?) cases the timezone per
> account is not needed. That being said, I was a bit nervous removing the
> option of adding timezones in the future, so I think this proposal better
> addresses the needs without restricting things in the future.
>
> Here's what I was thinking. The general idea is to allow "date only"
>> functionality, but also allow optional entry of a time of day:
>> 1. Let there be a checkbox preference named "Show transaction posting
>> times". Off by default.
>> 2. When this preference is off, registers look the same as today; a time
>> of
>> day is not seen and cannot be entered.
>> 3. When this preference is on, users can enter a posting time of day on
>> any
>> transaction, but do not have to.
>> 4. For each transaction, if a time of day has not been entered then the
>> GnuCash data file will only save the date. Otherwise, both date and the
>> time
>> of day will be saved.
>
>
> This is likely to become messy in the datafile: some dates without times
> and some with times. When we read this data in, we would have to keep track
> of which dates have times and which do not. I'd think it would be much
> simpler to create a default time and always write out the time (assuming, of
> course, that the user had not specified a time). And since the timezone is
> always known, there will never be any ambiguity or shifting dates.
>

I believe several users have expressed that they do not want a time written
to their data file if they never actually entered one. That's one of the
things I am proposing to support with this proposal. Saving defaulted
transaction times would mean that when you read the file back in, you
wouldn't know which times were user-entered and which times were defaulted.


> 5. The user does not specify any time zone, and none is saved.
>
>
> ok, though I'd advocate that the timezone be specified (and possibly saved)
> as UTC. If we do not do this, the user may decide to change the timezone on
> their machine while gnucash is open and possibly save different data than
> was read in.
>

Under this proposal, the time zone on the machine is completely ignored. The
time zone is a constant set internally by GnuCash. So changing the machine's
time zone is not an issue.


> 6. In case the user has some transactions with times and some without, and
>> needs to sort transactions by posting time, let there be a preference
>> exists
>> to determine how to treat the transactions that do not have posting times.
>> (Possible options might include treating them as if they had been entered
>> at
>> the beginning of the day, or at the end of the day, or at any specific
>> time
>> in between.)
>
>
> I'd allow a default transaction time instead, as above.
>
> Sound good? Well, here's the part you may not like. All of the above can be
>> implemented by GnuCash internally by use of a timestamp and a flag
>> indicating whether the time of day was entered by the user. Let me
>> explain:
>> A. All timestamps would use the same time zone, which never varies. Users
>> do
>> not pick the time zone. It is hard coded and is never seen in the GUI and
>> never saved to the data file.
>
>
> Unless the user changes timezones with the file open...
>

GnuCash would ignore the system time zone.


>
> Nathan
>
> B. If a transaction is read from a data file and it contains both a date
>> and
>> a time, these are combined with the time zone from (A) to compute a
>> timestamp. The flag is raised to indicate that the time of day was entered
>> by the user.
>> C. If a transaction is read from a data file and it contains only a date,
>> a
>> time of day is added on according to the preference indicated in (6)
>> above,
>> and these are combined with the time zone from (A) to compute a timestamp.
>> The flag is lowered to indicate that the time of day was NOT entered by
>> the
>> user.
>> D. To display the date in the GUI, GnuCash takes the time zone from (A)
>> and
>> the timestamp, and uses them to compute the date.
>
> E. To (optionally) display the time in the GUI, GnuCash takes the time zone
>> from (A) and the timestamp, and uses them to compute the time of day.
>> F. When saving a transaction to the data file, if the flag is raised to
>> indicate that the time of day was entered by the user, then GnuCash writes
>> the date and time of day to the data file.
>> G. When saving a transaction to the data file, if the flag is lowered to
>> indicate that the time of day was NOT entered by the user, then GnuCash
>> writes only the date to the data file.
>>
>> My reasons for suggesting the continued use of timestamps internally are
>> that it makes it very easy to sort transactions by posting time, and that
>> the necessary code changes to get this done is still fairly small. So
>> there
>> is probably some reasonable chance of it actually getting done, which is
>> an
>> important factor to consider. Several of you who want to use "date only"
>> internally have made fair points about simplicity, but I have made the
>> point
>> that the effort of getting from here to there would be much larger. So you
>> would have to ponder the question of who would devote the necessary time
>> for
>> that larger effort.
>>
>> OK, now praise this, ask questions, or rip it apart (more likely) as you
>> see
>> fit. Thanks to everyone so far for remaining fairly civil while discussing
>> this potentially incendiary topic.
>>
>> Cheers,
>> Charles
>>
>
-Charles