@jswhit, sorry for the delay in responding. > What is the rationale for allowing year zero in proleptic_gregorian, but not > in the Julian and mixed calendars? It seems more consistent to me to disallow > year zero for all 'real-world' calendars.
That is a fair question with a complicated answer. Here are the main arguments from my viewpoint. * Proleptic Gregorian is not a real-world calendar before the crossover year of 1582. It is an artificial calendar invented for mathematical convenience, for limited technical applications. * There is a strong need in science and technology for a mathematically simple calendar that goes backward indefinitely. In contrast, the real-world Julian and Gregorian calendars (not their current CF definitions) are constrained to only dates forward from a starting point or era in history. This desire for a systematic calendar extending backward puts Proleptic Gregorian into its own category. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/298*issuecomment-808569729__;Iw!!G2kpM7uM-TzIFchu!nOu5nF8rB6X3TMxi4vgFcTqg7D7HJVKWsexa3KZspDdu9Eb3t8h4SjW-107HTLB6obFPcAsHzDE$ This list forwards relevant notifications from Github. It is distinct from [email protected], although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to [email protected].
