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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/neps/datetime-proposal.rst | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/doc/neps/datetime-proposal.rst b/doc/neps/datetime-proposal.rst index 8c8c42167..f72bab3ae 100644 --- a/doc/neps/datetime-proposal.rst +++ b/doc/neps/datetime-proposal.rst @@ -92,7 +92,7 @@ A limited number of divisions of any basic unit can be used to create multiples of a higher-resolution unit provided the divisor can be divided evenly into the number of higher-resolution units available. For example: Y/4 is just short-hand for -> (12M)/4 -> 3M and Y/4 will be -represented 1after creation as 3M The first lower unit found to have an +represented after creation as 3M. The first lower unit found to have an even divisor will be chosen (up to 3 lower units). The following standardized definitions are used in this specific case to find acceptable divisors @@ -112,7 +112,6 @@ m 60s, 60000ms s, ms, us, ns, ps, fs (use 1000 and 1000000 of the next two available lower units respectively). - Finally, a date-time data-type can be created with support for tracking sequential events within a basic unit: [D]//100, [Y]//4 (notice the required brackets). These ``modulo`` event units provide the following @@ -618,6 +617,24 @@ list of tuples describing a data-format can itself be a tuple of Final considerations ==================== +Why the fractional time and events: [3Y/12]//50 +----------------------------------------------- + +It is difficult to come up with enough units to satisfy every need. For +example, in C# on Windows the fundamental tick of time is 100ns. +Multiple of basic units are simple to handle. Divisors of basic units +are harder to handle arbitrarily, but it is common to mentally think of +a month as 1/12 of a year, or a day as 1/7 of a week. Therefore, the +ability to specify a unit in terms of a fraction of a "larger" unit was +implemented. + +The event notion (//50) was added to solve a use-case of a commercial +sponsor of this NEP. The idea is to allow timestamp to carry both event +number and timestamp information. The remainder carries the event +number information, while the quotient carries the timestamp +information. + + Why the ``origin`` metadata disappeared --------------------------------------- |