from preamble:
"Change Set: DateAndTime Date: 21 October 2001 Author: Ross Boylan
This change set is an adaption and extension of Brent Pinkney's work to bring ANSI standard DateAndTime and Duration implementations to squeak. However, that work replaces the existing Date, Time, Week, and other classes, while this leaves them in place. The new analogues have DT prefixed to their names (e.g., DTDate, DTWeek). I have also removed various code that makes the new scheme the default for the whole system.
So this makes the new approach available, without mandating it or changing the rest of the system. I have used it in 3.1 and 3.2 alpha images.
Since someday these may become the standard classes in the image, I recomend NOT hardcoding these class names. Instead use DateAndTime dateClass and similar methods in the DateAndTime class migration protocol.
I have also made a few changes and extensions, notably providing more support for formatted printing and reading of DateAndTimes. The reading capabilities are still primitive. In particular, you must use 4 digits for the year.
See Brent's Swiki page http://minnow.cc.gatech.edu/squeak/1871 for more information and motivation.
Brent, who is currently on an extended vacation, is pinkfoot@bigfoot.com. Ross is RossBoylan@stanfordalumni.org"!
"Ross Boylan" RossBoylan@stanfordalumni.org wrote:
--==CelesteAttachment43625==
from preamble:
"Change Set: DateAndTime Date: 21 October 2001 Author: Ross Boylan
This change set is an adaption and extension of Brent Pinkney's work to bring ANSI standard DateAndTime and Duration implementations to squeak. However, that work replaces the existing Date, Time, Week, and other classes, while this leaves them in place. The new analogues have DT prefixed to their names (e.g., DTDate, DTWeek). I have also removed various code that makes the new scheme the default for the whole system.
Are you aware of the existing implementation of ANSI classes and methods by Richard Harmon?
http://minnow.cc.gatech.edu/squeak/2384
ANSI Squeak is here. Nobody seems to know about it.
-Lex
On Mon, Apr 29, 2002 at 12:08:07AM -0400, Lex Spoon wrote:
"Ross Boylan" RossBoylan@stanfordalumni.org wrote:
Are you aware of the existing implementation of ANSI classes and methods by Richard Harmon?
http://minnow.cc.gatech.edu/squeak/2384
ANSI Squeak is here. Nobody seems to know about it.
-Lex
That may have been the other implementation I was thinking of. I have not had much of a chance to compare them.
I do recall there was some implementation that said it was a bit of an experiment or an exercise. The classes I provided are pretty well worked through (not by me, but by Brent).
One problem I noticed is that the classes don't track changes to and from daylight savings time. This might be less of an issue on systems where the clock is set to UTC, but I find I need to reset the offset from UTC manually. Even if the clock is on UTC, presumably this would need to be reset to get the correct local wall-clock time. I'm not sure if this is specific to the DateAndTime classes in the enhancement I posted, or if other implementations (e.g., the classes in the base image) have similar problems.
I was told that the ANSI date/time stuff wasn't likely to go in the baseline image because it would be too disruptive. However, that might be less of an issue with classes that supplement, rather than replace, the existing Date and Time classes.
Ross Boylan RossBoylan@stanfordalumni.org wrote:
On Mon, Apr 29, 2002 at 12:08:07AM -0400, Lex Spoon wrote:
"Ross Boylan" RossBoylan@stanfordalumni.org wrote:
Are you aware of the existing implementation of ANSI classes and methods by Richard Harmon?
http://minnow.cc.gatech.edu/squeak/2384
ANSI Squeak is here. Nobody seems to know about it.
-Lex
That may have been the other implementation I was thinking of. I have not had much of a chance to compare them.
I do recall there was some implementation that said it was a bit of an experiment or an exercise. The classes I provided are pretty well worked through (not by me, but by Brent).
One problem I noticed is that the classes don't track changes to and from daylight savings time. This might be less of an issue on systems where the clock is set to UTC, but I find I need to reset the offset from UTC manually. Even if the clock is on UTC, presumably this would need to be reset to get the correct local wall-clock time. I'm not sure if this is specific to the DateAndTime classes in the enhancement I posted, or if other implementations (e.g., the classes in the base image) have similar problems.
Actually, if you additionally use my plugin for local time, then you get ANSI *and* proper local times, which track daylight savings equally as well as the underlying OS. I haven't gotten rebuilt the plugin in a while, but it shouldn't be hard if all the changesets can be located.... (No, I really don't know off the top of my head!)
I was told that the ANSI date/time stuff wasn't likely to go in the baseline image because it would be too disruptive. However, that might be less of an issue with classes that supplement, rather than replace, the existing Date and Time classes.
It seems the ANSI stuff *hasn't* gone in because it *might* be disruptive. I've always expected, however, that they would go in eventually. Who knows?
By the way, DateAndTime (or Chris's Timestamp) is a useful class to have around. This isn't just about makeing Squeak standard -- ANSI has made improvements. Notice, for example, that local time and UTC time might have different dates; the fact that date and time are combined makes this easy to deal with. Existing Squeak code passes around 2-element arrays when this need arises.
Lex
On Mon, Apr 29, 2002 at 01:32:52PM -0400, Lex Spoon wrote:
Ross Boylan RossBoylan@stanfordalumni.org wrote:
One problem I noticed is that the classes don't track changes to and from daylight savings time. This might be less of an issue on systems where the clock is set to UTC, but I find I need to reset the offset from UTC manually. Even if the clock is on UTC, presumably this would need to be reset to get the correct local wall-clock time. I'm not sure if this is specific to the DateAndTime classes in the enhancement I posted, or if other implementations (e.g., the classes in the base image) have similar problems.
Actually, if you additionally use my plugin for local time, then you get ANSI *and* proper local times, which track daylight savings equally as well as the underlying OS.
And of course http://minnow.cc.gatech.edu/squeak/1076 for the really over the top everything you ever wanted to know about leap seconds but were afraid to ask version.
Dave
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