This is a good set of cleanups, with an overall performance improvement.

+1 for moving the changes to trunk, with or without the DateAndTime>>#=  change.

I somewhat agree with Eliot's comment below, although I am happy either way.

Dave


On Mon, Jan 14, 2019 at 07:07:23AM -0800, Eliot Miranda wrote:
> Hi Levente,
> 
> > On Jan 14, 2019, at 4:18 AM, commits at source.squeak.org wrote:
> > 
> > Levente Uzonyi uploaded a new version of Chronology-Core to project The Inbox:
> > http://source.squeak.org/inbox/Chronology-Core-ul.22.mcz
> > 
> > ==================== Summary ====================
> > 
> > Name: Chronology-Core-ul.22
> > Author: ul
> > Time: 14 January 2019, 1:08:48.177246 pm
> > UUID: 025b4802-6281-4674-937e-a345e5a6aded
> > Ancestors: Chronology-Core-ul.21
> > 
> > - added an accessor to Time's ClockPolicy, so that tests can depend on its current value
> > - optimized various DateAndTime methods
> > 
> > =============== Diff against Chronology-Core-ul.21 ===============
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>= (in category 'ansi protocol') -----
> >  = aDateAndTimeOrTimeStamp
> >      "Equal if the absolute time values match, regardless of local time transform"
> > + 
> >      self == aDateAndTimeOrTimeStamp ifTrue: [ ^ true ].
> > +    aDateAndTimeOrTimeStamp species == DateAndTime ifFalse: [ ^false ].
> > +    aDateAndTimeOrTimeStamp utcMicroseconds = utcMicroseconds ifTrue: [ ^true ].
> > +    ^false!
> > -    ^aDateAndTimeOrTimeStamp species == DateAndTime
> > -        and: [ utcMicroseconds = aDateAndTimeOrTimeStamp utcMicroseconds ]!
> 
> Can we please avoid the ... ifFalse: [^false] style and keep the much nicer concise and: style?  Yes, the former is slightly faster, but not by much, and the JIT has code to minimize the difference and Sista will eliminate the difference.  The former style is so ugly.
> 
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>asUTC (in category 'ansi protocol') -----
> >  asUTC
> > 
> >      localOffsetSeconds = 0 ifTrue: [ ^self ].
> > +    ^self copy makeUTC!
> > -    ^self copy
> > -        utcMicroseconds: utcMicroseconds
> > -        offset: 0
> > - !
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>asUnixTime (in category 'squeak protocol') -----
> >  asUnixTime
> >      "answer number of seconds since unix epoch (midnight Jan 1, 1970, UTC)"
> > 
> > +    ^utcMicroseconds // 1000000!
> > -    ^(self - self class unixEpoch) asSeconds!
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>dayMonthYearDo: (in category 'squeak protocol') -----
> >  dayMonthYearDo: aBlock
> >      "Evaluation the block with three arguments: day month, year."
> > 
> > +    | l n i j dd |
> > -    | l n i j dd mm yyyy |
> >      l := self julianDayNumber + 68569.
> >      n := 4 * l // 146097.
> >      l := l - (146097 * n + 3 // 4).
> > +    i := l + 1 * 4000 // 1461001.
> > -    i := 4000 * (l + 1) // 1461001.
> >      l := l - (1461 * i // 4) + 31.
> >      j := 80 * l // 2447.
> >      dd := l - (2447 * j // 80).
> >      l := j // 11.
> > -    mm := j + 2 - (12 * l).
> > -    yyyy := 100 * (n - 49) + i + l.
> > 
> >      ^ aBlock
> >          value: dd
> > +        value: -12 * l + 2 + j "month"
> > +        value: n - 49 * 100 + i + l "year"!
> > -        value: mm
> > -        value: yyyy!
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>floor (in category 'squeak protocol') -----
> >  floor
> >      "Answer a copy with magnitude rounded down to the nearest whole second"
> >      ^self class
> > +        utcMicroseconds: utcMicroseconds // 1000000 * 1000000
> > -        utcMicroseconds: utcMicroseconds - (utcMicroseconds \\ 1000000)
> >          offset: localOffsetSeconds!
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>getSeconds (in category 'accessing') -----
> >  getSeconds
> > +    
> > +    ^utcMicroseconds // 1000000 + localOffsetSeconds \\ 86400!
> > - 
> > -    | posixDays posixSeconds localSeconds |
> > -    posixSeconds := utcMicroseconds // 1000000.
> > -    localSeconds := posixSeconds + localOffsetSeconds.
> > -    localSeconds < 0 ifTrue: [localSeconds := localSeconds \\ SecondsInDay]. "normalize"
> > -    posixDays := localSeconds // SecondsInDay.
> > -    ^localSeconds - (posixDays * SecondsInDay).
> > - !
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>julianDayNumber (in category 'squeak protocol') -----
> >  julianDayNumber
> > 
> > +    ^utcMicroseconds // 1000000 + localOffsetSeconds // 86400 + PosixEpochJulianDays!
> > -    | posixDays posixSeconds localSeconds negativeDays |
> > -    posixSeconds := utcMicroseconds // 1000000.
> > -    localSeconds := posixSeconds + localOffsetSeconds.
> > -    negativeDays := 0.
> > -    localSeconds < 0 ifTrue: [ "normalize"
> > -            negativeDays := localSeconds // SecondsInDay.
> > -            localSeconds := negativeDays * SecondsInDay + localSeconds].
> > -    posixDays := localSeconds // SecondsInDay.
> > -    ^posixDays + PosixEpochJulianDays - negativeDays.
> > - !
> > 
> > Item was changed:
> >  ----- Method: DateAndTime>>microsecondsFromDay:seconds:nanos:offset: (in category 'private') -----
> >  microsecondsFromDay: jdn seconds: s nanos: n offset: localOffsetSeconds
> > 
> > +    ^jdn - PosixEpochJulianDays "days" * 86400
> > +        + s - localOffsetSeconds "seconds" * 1000000
> > +        + (n / 1000) "nanos"!
> > -    | days totalSeconds micros |
> > -    days := jdn - PosixEpochJulianDays.
> > -    totalSeconds := days * 86400 + s - localOffsetSeconds. "n.g. const 86400 is faster than SecondsInDay"
> > -    micros := totalSeconds * 1000000.
> > -    ^micros + (n / 1000)
> > - !
> > 
> > Item was added:
> > + ----- Method: Time class>>clockPolicy (in category 'class initialization') -----
> > + clockPolicy
> > + 
> > +    ^ClockPolicy!
> > 
> > 
>