On Wed, Aug 18, 2010 at 04:30:02PM -0700, Andreas Raab wrote:
> Hi -
> 
> I've noticed a while ago that at some point in the evolution of Squeak 
> both Time as well as DateAndTime had "nano seconds" added. 
> Unfortunately, the default printing of both of these classes leads to 
> some extremely strange effects now. For example, where historically 
> something like
> 
> 	DateAndTime now asUTC.
> 
> would print "2010-08-18T23:23:54+00:00" it now prints silly nonsense 
> like this: "2010-08-18T23:17:49.888000007+00:00" (I just found this in 
> one of our log files). Similarly, if you evaluate "Time now" you get 
> results like "4:22:07.369 pm".
> 
> In short, the question is: Is there any point whatsoever to print 
> fractional seconds by default? It seems to me that if you need to print 
> fractional seconds you might as well use some other selector and leave 
> #printOn: with the historical behavior of not printing fractional seconds.

Ick. There is no justification for printing fractional seconds in this
context, because we expect the #printString to resemble a standard date
string.

Regrettably, the offending method DateAndTime>>printOn:withLeadingSpace:
is stamped with my initials from 10/31/2004 in this change set:

  Change Set:   DateAndTimePrintOnFix-dtl
  Date:         5 November 2004
  Author:       David T. Lewis
  
  The #printOn: for DateAndTime did not insert a decimal point for the
  fractional part of seconds (nanoseconds). This change set provides a fix.

But I think that this was a cosmetic fix to a method that entered the
image some time after Squeak 3.6.

Until recently, "DateAndTime now" answered an object with no nanoseconds,
so the fractional seconds printing feature was not visible. At some point
in recent Squeak history, "DateAndTime now" began producing instances
with non-zero nonos fields. This is a good thing, but it has the side
effect of triggering the fractional seconds printing (mis)feature in
DateAndTime>>printOn:withLeadingSpace: which is not a good thing.

Note, if you open a Squeak 3.8 image, inspect "DateAndTime now", then
set the nanos instance variable to some non-zero value, you will see
the same questionable #printString behavior.

> Anyone in favor of preserving fractional seconds by default please raise 
> your hand and provide some arguments why such behavior would be preferable.

No. It is nice to display the fractional seconds, but not by default in
the #printOn: method. A different selector might be a acceptable, perhaps
something like #printOn:withLeadingSpaces:withFractionalSeconds:

<OT>
IMHO, the meta-issue is that time should be represented as a simple
magnitude rather than as a mashup of discreet whole numbers (the instance
variables in DateAndTime) passing through various transformations to
represent durations or to display time and date strings.
</OT>

Dave