https://hackage.haskell.org/package/period
Library and executable to parse and format date periods, collapse and expand, e.g. 2018 → 2018-01-01,2018-12-31 and backwards.
Usage: period COMMAND
Expand or collapse text representation of date range.
period collapse 2018-01-01,2018-12-31
=> 2018
period collapse 2018-01-01,2118-12-31
=> 2018,2118
period expand 2018-01
=> 2018-01-01,2018-01-31
period expand 2018-01-07,14
=> 2018-01-07,2018-01-14
Available options:
-h,--help Show this help text
Available commands:
collapse Find shortest representation for time period
expand Display start and end points of time period