[TUHS] History of cal(1)?

[John Levine via TUHS]

It appears that Dan Cross via TUHS <crossd at gmail.com> said:
>My suspicion is that it was not, and this is a case of parallel
>invention: after all, a program that prints out a calendar is
>obviously useful. ...

It is, but a program that has all the logic to adjust for 16th century
calendar changes, not so much.  (Try "cal 9 1752")

My impression is that the Unix cal program was always this overimplemented
so perhaps we can see whether other earlier programs did that too.

R's,
John