There is more:
1) hasEqualTicks: use julianDayNumber instead of julianDayNumberUTC
2) (Time dateAndTime now) interprets the (Time localSeconds) which are from
the wrong primitive (seconds ellapsed since squeak epoch translated to
local time) as seconds ellapsed since squeak Epoch (UTC time).
We should really ban the old primitive 137 and only use the new one (240
which works with UTC microseconds).
I think Camillo did a good job, but he stopped cleaning too soon.
Ah, young guys are so impatient to invent the future ;)
2013/4/27 stephane ducasse <stephane.duca...@free.fr>
>
> On Apr 27, 2013, at 6:33 PM, Nicolas Cellier <
> nicolas.cellier.aka.n...@gmail.com> wrote:
>
> > Since DateAndTime comment is out of date (sic !) and current
> implementation seems not free of bug, here is an effort to summarize and
> understand the whole thing, let's call this a review.
>
> Thanks this is a great initiative!
>
>
> > Please tell me where my interpretations are wrong.
> >
> > 1) The DateAndTime is stored internally as
> > - a point in UTC time (julianDayNumber, seconds, nanos)
> > - an offset from UTC (a Duration) denoting the local time zone
> >
> > 2) The ticks method returns the UTC part {julianDayNumber. seconds.
> nanos}
> >
> > 3) DateAndTime print themselves in local time using the offset
> >
> > 4) other methods (with some exceptions) return the local dateAndTime
> parts (year month day hours minutes seconds)
> >
> > Exceptions are:
> > - secondsSinceMidnight (which should be renamed secondsSinceMidnightUTC
> IMO, even if the method is classified private)
> > - julianDayNumberUTC as the name tells
> >
> > So far so good (but secondsSinceMidnight which is error prone)
> >
> > What I find strange:
> > - #hash uses the offset... Why ???
> >
> > d1 := DateAndTime now.
> > d2 := d1 offset: d1 offset + 1 hours.
> > {
> > d1 = d2.
> > d1 hash = d2 hash.
> > }
> > gives #(true false), a clue?
> >
> > - #< compares julianDayNumber (the UTC inst. var.) with otherDate
> julianDayNumber (with otherDate local offset) which seems wrong, it should
> better use julianDayNumberUTC or (normalized) ticks.
> >
> > - #= could be simplified and accelerated if using #hasEqualTicks: (if
> the ticks are correctly normalized though which would be the case since
> #ticks:offset: does, unfortunately #setJdn:seconds:nanos:offset: does not).
> >
> > Some senders of #setJdn:seconds:nanos:offset: don't normalize the
> day/seconds/nanos, though it should be their responsibility (DateAndTime
> todayAtMilliSeconds: xxx) (DateAndTime todayAtNanoSeconds: xxx), not
> counting year:month:day:hour:minute:second:nanoSecond:offset: which does
> not either (many senders...).
> > Maybe we should better let the normalization responsibility to
> #setJdn:seconds:nanos:offset:.
> >
> > It remain to analyze the conversion protocol (asYear etc...) which seems
> to use the local time year, but I don't understand the whole Timespan thing
> right now (why DateAndTime now asYear starts now, and not on january 1st?).
> >
> > Nicolas
> >
> >
>
>
>
