calconnect-ci
commented
4 years ago In GitLab by @ronaldtse on Sep 6, 2018, 09:05
Thanks for bringing this up. Notice that this representation does not allow negative integers, and it is an intentional omission in ISO 8601-2 -- I wrote it but it was removed afterwards. This also applies to the "Century" time scale component; negative century is not allowed.
The reason for removal is the confusion it may cause in the AD/BC calendar year scale. 8601 adopts the astronomical year scale that allows a year 0. There is no "0" year in AD/BC, it's 1 AD followed by 1 BC. Therefore, in 8601, year "0" means "1 BC".
I am however inclined to allow negative values for these, but it is not straightforward.
Original text for negative decade:
4.4.6 Decade and decade duration
The decade is represented as follows extending 4.3.3: Explicit: decE(m) = [!][“-”][decE]
EXAMPLE: ‘-10U’ in date represents the time interval of Gregorian years -100 through -91.
When a negative decade represents a date, the negative value is to represent the number of decades prior to the Gregorian year 0, where the first decade before the Gregorian year 0, the Gregorian years -1 through -10, is represented by the integer value ‘-1’.
- "0U" actually means years 0 to 9 (1 BC to 9 AD)
- "-1U" means years -10 to -1 (11 BC to 2 BC)
- etc.
Here's the problem with expressing "the fifty years preceding 400BCE":
- "400BC" is year "-399"
- We want to express years "-449" to "-400"
- The closest in decade representation would be "-45U" which gives years -450 to -441, which is "451 BC" to "442 BC".
The only way to express this using this document (this expression cannot be expressed in normal 8601) is:
- In time interval form one would write "-449Y/-400Y"
Let's discuss.
In GitLab by @ribose-jeffreylau on Sep 6, 2018, 08:07
Created by: atlauren
Examples should include indications to anticipated, albeit noncommon, representations.
'0U' (years 00-09 CE)
(How would one represent "the fifty years preceding 400BCE"?)