ChuQL adds support for Map/Reduce to XQuery

mapreduce {
  input { fn:collection("hdfs://input/") }
  rr { for $line at $i in $in//line return { key: $i, val: $line } }
  map { for $word in fn:tokenize($in=>val, " ")
  return { key: $word, val: 1 } }
  reduce { { key: $in=>key, val: fn:count($in=>val) } }
  rw { <word text="{$in=>key}" count="{$in=>val}"/> }
  output { fn:put($in,"hdfs://output/") }
}

See ceur-ws.org/Vol-749/paper25.pdf.

Seems like a plausible feature that would make XQuery much more useful for Big Data.