Re: Software Engineering News Brief

[eggert@twinsun.com (Paul Eggert)]

dewar@merv.cs.nyu.edu (Robert Dewar) writes:

> To accept dates before the 18th century without comment or error,
> and then misinterpret them seems highly error prone.

On the contrary, I've helped write some applications where quietly
accepting pre-18th-century dates was precisely the right thing to do.
A calendar package should not presume to tell applications what the
proper range is -- it should support the calendar,
and let applications worry about data validity checking.

> All countries agree for the Ada range of dates

That is not true for the early part of this century, when many
countries still used the Julian calendar for most purposes; it's not
even entirely true now, as some countries still use non-Gregorian
calendars for some legal purposes.  (And whether it will be true through
the year 2099 is more than either you or I can say.  :-)

But all this is irrelevant for the Ada calendar package, which
(understandably) supports only the Gregorian calendar.

> I am pretty sure that when people talk about Gregorian dates, they do not
> mean what they say (i.e. they are not talking about dates according to the
> scheme that Pope Gregory decreed)....

There isn't any real disagreement about what `Gregorian' means these days
(except perhaps before the year 1).  If there were real disagreement,
then even the limited-range Ada calendar package would be questionable.