CVS difference for ais/ai-00160.txt

Differences between 1.8 and version 1.9
Log of other versions for file ais/ai-00160.txt

--- ais/ai-00160.txt	2000/08/01 05:39:34	1.8
+++ ais/ai-00160.txt	2004/06/10 05:39:55	1.9
@@ -687,3 +687,46 @@
 function Message (Text: in Clever_Ideas) return Better_Ideas is...
 
 ****************************************************************
+
+!topic Time_Of for a non existing time of day
+!reference RN95-9.6(25-26)
+!from Vincent Celier 2004-05-31
+!keywords Calendar Time_Of Split
+!discussion
+
+RM-9.6(26) says that exception Time_Error is raised if the parameters of
+Time_Of do not form a proper date. However, nothing is said about not
+forming a proper time of day.
+
+Consider the following case, in New York, where the Time Zone is
+EST/EDT.
+
+T := Time_Of (Year => 1998, Month => 4, Day => 5, Seconds => 10740.0);
+
+On this day, April 5th 1998, there is a switch from EST to EDT. The
+clock goes directly from 2:30AM to 3:30AM.
+
+The parameter Seconds specifies a time of day of 2:59:00. This time of
+day does not exist.
+
+Should this call to Time_Of raises Time_Error? (No)
+
+What should be the value of out parameter Seconds, when Split is called
+on the Time value T?
+
+Can it be 10740.0 ?
+Should it be 14340 (corresponding to 3:59:00) ?
+Could it be any one of these two values? (I would say Yes).
+
+****************************************************************
+
+From: Randy Brukardt
+Sent: Tuesday, June  1, 2004  3:42 PM
+
+This topic was "decided" by AI-160; essentially what happens for daylight
+savings time is implementation-defined.
+
+I don't think the time zone operations in AI-351 will have any impact on
+this result (given that the time zone itself is implementation-defined).
+
+****************************************************************

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