[TUHS] History of cal(1)?

[Rob Pike via TUHS]

There are so many calendars in the world. The Muslim calendar. The Jewish
calendar. The Mayan calendar. Countless indigenous calendars too, I am
certain.

Whenever computing butts up against real human culture, things get messy
fast. No point in trying to catalog the mess exhaustively.

-rob


On Tue, Sep 23, 2025 at 11:14 AM Steffen Nurpmeso via TUHS <tuhs at tuhs.org>
wrote:

> John Levine via TUHS wrote in
>  <20250923003454.03671DD56E9A at ary.qy>:
>  |It appears that Douglas McIlroy via TUHS <douglas.mcilroy at dartmouth.edu>
> \
>  |said:
>  |>> [cal(1)] has all the logic to adjust for 16th century
>  |>> calendar changes ...  (Try "cal 9 1752")
>  |>> My impression is that [it is] overimplemented.
>  |>
>  |>The fact that a 16th century change is illustrated by an 18th century
>  |>example suggests that not quite "all the logic" is there. It's good
>  |>for Great Britain and its colonies, but not elsewhere. So I'd say it's
>  |>underimplemented :)
>  |
>  |You'll be relieved to know that ncal has addressed that omission:
>  |
>  |$ ncal -p
>  | AL Albania        1912-11-30      IS Iceland        1700-11-16
>  | AT Austria        1583-10-05      IT Italy          1582-10-04
>  | AU Australia      1752-09-02      JP Japan          1918-12-18
>  | BE Belgium        1582-12-14      LT Lithuania      1918-02-01
>  | BG Bulgaria       1916-03-31      LU Luxembourg     1582-12-14
>  | CA Canada         1752-09-02      LV Latvia         1918-02-01
>  | CH Switzerland    1655-02-28      NL Netherlands    1582-12-14
>  | CN China          1911-12-18      NO Norway         1700-02-18
>  | CZ Czech Republic 1584-01-06      PL Poland         1582-10-04
>  | DE Germany        1700-02-18      PT Portugal       1582-10-04
>
> (In an earlier thread on this topic Mr. McIlroy threw into
> the discussion that for example Germany was very much more
> complicated than that.  And i said iirc something like "we
> tried to keep it local by then" [actually notoriously so], and
> unfortunately talked about Mors Teutonicus even, as "we more
> usually than not reached the Holy Land" before reaching the holy
> land, which *possibly* is the only one and true way to reach the
> holy land .. if you can.  (Pffffhh, what a talk.))
>
>  | DK Denmark        1700-02-18      RO Romania        1919-03-31
>  | ES Spain          1582-10-04      RU Russia         1918-01-31
>  | FI Finland        1753-02-17      SI Slovenia       1919-03-04
>  | FR France         1582-12-09      SE Sweden         1753-02-17
>  | GB United Kingdom 1752-09-02      TR Turkey         1926-12-18
>  | GR Greece         1924-03-09     *US United States  1752-09-02
>  | HU Hungary        1587-10-21      YU Yugoslavia     1919-03-04
>  |
>  |R's,
>  |John
>  |
>  |PS: my point was not that it's a lot of code, but that is's a
> distinctive \
>  |hack so one might
>  |look at earlier calendar programs to see whether they also did it to \
>  |try and trace the
>  |chain of influence.
>  --End of <20250923003454.03671DD56E9A at ary.qy>
>
> --steffen
> |
> |Der Kragenbaer,                The moon bear,
> |der holt sich munter           he cheerfully and one by one
> |einen nach dem anderen runter  wa.ks himself off
> |(By Robert Gernhardt)
>