aggregate function metadata

aggregates.xqy

xquery version "1.0-ml";

declare variable $numeric-scalar-types := ("int", "unsignedInt", "long", "unsignedLong", "float", "double", "decimal");

declare function local:scalar-types()
{
  xdmp:read-cluster-config-file("database.xsd")/xs:schema
    /xs:simpleType[@name eq "scalar-type"]/xs:restriction/xs:enumeration/@value/fn:string()
};

declare function local:aggregate-types()
{
  map:new((
    (: TODO: test :)
    ("covariance", "covariance-population", "correlation") !
      map:entry(., $numeric-scalar-types),
    ("median", "stddev", "stddev-population", "variance", "variance-population") !
      map:entry(., $numeric-scalar-types),
    ("sum", "avg") !
      map:entry(., ($numeric-scalar-types, "yearMonthDuration", "dayTimeDuration")),
    ("min", "max") !
      map:entry(., ($numeric-scalar-types, "point", "yearMonthDuration", "dayTimeDuration", "date", "dateTime", "time", "gYear", "gMonth", "gYearMonth", "gDay")),
    map:entry("count", ("point", local:scalar-types()))))
};

declare function local:aggregate-info()
{
  map:new((
    ("covariance", "covariance-population", "correlation") !
      map:entry(., 
        map:entry("reference-arity", 2)),
    map:keys(local:aggregate-types())[fn:not(. = ("covariance", "covariance-population", "correlation"))] !
      map:entry(., 
        map:entry("reference-arity", 1))))
};

declare function local:map-values-as-arrays($map as map:map) as map:map
{
  map:new(
    for $key in map:keys($map)
    let $val := map:get($map, $key)
    return
      map:entry($key,
        if ($val instance of json:array)
        then $val
        else json:to-array($val)))
};

xdmp:to-json(
  map:new((
    map:entry("info", local:aggregate-info()),
    map:entry("by-type",
      local:map-values-as-arrays(
        -local:aggregate-types())))))