[LEAPSECS] Actual versus legal duration makes programming hard

[G Ashton]

People intentionally throw information away, for certain purposes, even when
the information is not totally expunged. For example, when a baseball batter
ends his at-bat, the information about the number of strikes and balls
becomes irrelevant; all that matters, as far as the outcome of the game is
concerned, is if the batter was out,  got on base, or scored a home run. But
some other information about the at-bat is retained to determine how
fatigued the pitcher is likely to be, or determining the batter's batting
average.

Similarly, for many legal purposes, a day is a day is a day; time of day is
of no concern except to demarcate one day from the next. But sometimes
duration in days, hours, minutes, and seconds matter (for example, when
determining the pay of an hourly worker). So sometimes programmers have to
ignore daylight saving time leaps; in other situations they have to account
for them. Rules exist for this, although one might have to get a law degree
to understand the rules.

Rules for deciding when to count leap seconds and when to ignore them are
not fully developed; it's entirely understandable that programmers have
trouble programming in an environment where there is no universal agreement
on the rules.