handle decision on `cei:date` and `cei:dateRange` for chronological ordering in a common function
Created by: GVogeler
As https://github.com/icaruseu/mom-ca/blob/master/my/XRX/src/mom/app/charters/charters.xqm#L80-L83 handle the same problem as the solution of https://github.com/icaruseu/mom-ca/pull/751 if would suggest to move the solution from https://github.com/icaruseu/mom-ca/issues/679#issuecomment-342526594 into a common function in charters.xqm:
declare function charters:date-selector($cei_issued, $range_limit as xs:string?) as xs:string {
(:
The function decides which dating element is the most expressive in a cei:issued structure:
$cei_issued is the cei:issued element which contains either cei:date/@value or cei:dateRange/(@from|@to) or both.
$range_limit indicates if the function should return the lower or the upper value of cei:dateRange
Strategy is:
1. the lower value is preferred (to get the dates below the generic "unknown" value '99999999')
2. if that does not help cei:date is preferred against cei:dateRange
:)
let $rl := if(count($range_limit) = 0) then ('from') else ($range_limit)
let $date := $cei_issued/(
cei:date[
not(../cei:dateRange)
or xs:integer(@value) lt xs:integer(../cei:dateRange/@*[name()=$range_limit])
or xs:integer(@value) = xs:integer(../cei:dateRange/@*[name()=$range_limit])
]/@value
|
cei:dateRange[
not(../cei:date)
or xs:integer(@*[name()=$range_limit]) lt xs:integer(../cei:date/@*[name()=$range_limit])
]/@*[name()=$range_limit]
)
return $date[1]/string()
};